Biology Final Exam Review Part 2 Mrs. Depasse. Chapter 9 Cell Reproduction – The hereditary...
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Biology Final Exam Review Part 2 Mrs. Depasse. Chapter 9 Cell Reproduction – The hereditary information in all cells is deoxyribonucleic acid (DNA) Most
Chapter 9 Cell Reproduction The hereditary information in all
cells is deoxyribonucleic acid (DNA) Most of the time, the DNA in
each chromosome is wound around proteins called histones These
DNA-histone spools are further folded into coils Each DNA molecule
consists of a long chain composed of smaller subunits called
nucleotides Each nucleotide consists of a phosphate, a sugar
(deoxyribose), and one of four basesadenine (A), thymine (T),
guanine (G), or cytosine (C)
Slide 3
Figure 9-1 The structure of DNA nucleotide phosphate base sugar
A single strand of DNAThe double helix
Slide 4
Types of Cells 1.Stem cells 2.Other cells capable of dividing
3. Permanently differentiated cells Stem cells have two important
characteristics: self- renewal, and the ability to differentiate
into a variety of cell types Stem cells self-renew because they
retain the ability to divide, perhaps for the entire life of the
organism Stem cells include most of the daughter cells formed by
the first few cell divisions of a fertilized egg, as well as a few
adult cells
Slide 5
Types of cells Other cells capable of dividing Many cells of
the bodies of embryos, juveniles, and adults can divide Each type
of cell typically differentiates into only one or two types of
cells Dividing liver cells, for example, can only become more liver
cells Permanently differentiated cells differentiate and never
divide again
Slide 6
Sexual Reproduction Sexual reproduction in eukaryotic organisms
occurs when offspring are produced by the fusion of gametes (sperm
and eggs) from two adults Cells in the adults reproductive system
undergo a specialized type of cell division called meiotic cell
division Products of meiotic cell division, such as gametes, have
exactly half the genetic information of their parent cells and
reestablish the full genetic complement when they fuse
Slide 7
Asexual Reproduction Reproduction in which offspring are formed
from a single parent, without having a sperm fertilize an egg, is
called asexual reproduction Clones are offspring genetically
identical to the parent and to each other, produced through asexual
reproduction Bacteria and single-celled eukaryotic organisms
reproduce asexually
Slide 8
Figure 9-3 The prokaryotic cell cycle cell division by
prokaryotic fission cell growth and DNA replication The prokaryotic
cell cycleProkaryotic fission The parent cell divides into two
daughter cells. The plasma membrane grows inward at the middle of
the cell. New plasma membrane is added between the attachment
points, pushing the two chromosomes farther apart. The DNA
replicates and the resulting two chromosomes attach to the plasma
membrane at nearby points. The prokaryotic chromosome, a circular
DNA double helix, is attached to the plasma membrane at one point.
attachment site of chromosome cell wall plasma membrane
chromosome
Slide 9
Eukaryotic chromosomes Eukaryotic chromosomes usually occur in
pairs with similar genetic information A typical human cell has 23
pairs of chromosomes, for a total of 46 Twenty-two out of 23 pairs
are called autosomes Autosomes have similar appearance and similar
DNA sequences, and are paired in diploid cells of both sexes The
twenty-third pair is called sex chromosomes and is different in the
male and the female
Slide 10
Misc. The female has two X chromosomes that usually look
similar The male has an X and a Y chromosome that appear very
different Enduring mutations, inherited generation after
generation, are called alleles Cells in the ovaries and testes
undergo meiotic cell division and produce gametes (eggs and sperm)
that only have one member of each chromosome pair These kinds of
cells are called haploid
Slide 11
Haploid vs. Diploid In biological shorthand, the haploid
chromosome number is designated n, whereas the diploid number is 2n
In humans n = 23; 2n = 46
Slide 12
Meiosis Most eukaryotic cells spend the majority of their time
in interphase Interphase is divided into three phases 1. G 1
(growth phase 1) is a time for acquisition of nutrients and growth
to proper size 2. S (synthesis phase) is characterized by DNA
synthesis, during which every chromosome is replicated 3. G 2
(growth phase 2) includes completion of cell growth and preparation
for division of the cell into daughter cells
Slide 13
Figure 9-8 The eukaryotic cell cycle G 1 : cell growth and
differentiation telophase and cytokinesis anaphase metaphase
prophase S: synthesis of DNA; duplication of chromosomes G 2 : cell
growth and preparation for cell division
Slide 14
Mitotic Cell Division Mitotic cell division is the division of
one parental cell into two daughter cells; it consists of two
processes: mitosis and cytokinesis Mitosis is the division of the
nucleus During mitosis (nuclear division), the nucleus of the cell
and the chromosomes divide Each daughter nucleus receives one copy
of each of the replicated chromosomes of the parent cell During
cytokinesis (cytoplasmic division), the cytoplasm is divided
roughly equally between the two daughter cells, and one daughter
nucleus enters each of the daughter cells
Slide 15
Mitosis Mitosis has four main phases based on appearance and
behavior of the chromosomes 1.Prophase 2.Metaphase 3.Anaphase
4.Telophase
Slide 16
Prophase The first phase of mitosis is prophase (the stage
before in Greek) Five major events occur during prophase
1.Duplicated chromosomes condense 2.Spindle microtubules form -Two
types of spindle microtubules form: polar microtubules and
kinetochore, a protein-containing structure located at the
centromere 3.Nuclear envelope breaks down 4.Chromosome condensation
causes nucleolus to dissipate 5.Chromosomes are captured by the
spindle microtubules
Slide 17
Figure 9-9-1 Mitotic cell division in an animal cell
INTERPHASEMITOSIS nuclear envelope chromatin nucleolus centriole
pairs condensing chromosomes beginning of spindle formation spindle
pole kinetochore microtubules spindle microtubules spindle pole
Late Interphase Duplicated chromosomes are in the relaxed
uncondensed state; duplicated centrioles remain clustered. Early
Prophase Chromosomes condense and shorten; spindle microtubules
begin to form between separating centriole pairs. Late Prophase
(also called Prometaphase) The nucleolus disappears; the nuclear
envelope breaks down; some spindle microtubules attach to the
kinetochore (blue) located at the centromere of each sister
chromatid. Metaphase Kinetochore microtubules line up the
chromosomes at the cells equator.
Slide 18
Figure 9-9-2 Mitotic cell division in an animal cell MITOSIS
Anaphase Sister chromatids separate and move to opposite poles of
the cell; polar microtubules push the poles apart. INTERPHASE
Telophase One set of chromosomes reaches each pole and begins to
decondense; nuclear envelopes start to form; nucleoli begin to
reappear; spindle microtubules begin to disappear; microfilaments
form rings around the equator. Cytokinesis The ring of
microfilaments contracts, dividing the cell in two; each daughter
cell receives one nucleus and about half of the cytoplasm.
Interphase of daughter cells Spindles disappear, intact nuclear
envelopes form, and the chromosomes extend completely. polar
microtubules chromosomes extending nuclear envelope re-forming
microfilamentsnucleolus reappearing
Slide 19
Figure 9-10 Cytokinesis in a plant cell cell plate forming a
new cell wall Golgi apparatus cell wall plasma membrane
carbohydrate- filled vesicles Carbohydrate-filled vesicles bud off
the Golgi apparatus and move to the equator of the cell. The
vesicles fuse to form a new cell wall (red) and plasma membrane
(yellow) between the daughter cells. Complete separation of the
daughter cells.
Slide 20
CDKs The cell cycle is driven by proteins called cyclin-
dependent kinases, or CDKs Kinases are enzymes that phosphorylate
(add a phosphate group to) other proteins, stimulating or
inhibiting the proteins activity
Slide 21
Figure 9-11 Growth factors stimulate cell division
(interstitial fluid) cyclin- dependent kinase (Cdk) Cyclin binds to
Cdk cyclin Cyclin activates Cdk; active Cdk stimulates DNA
replication plasma membrane Cyclins are synthesized growth factor
receptor Growth factor binds to its receptor (cytosol) growth
factor
Slide 22
Meiosis Meiosis is a specialized cell division process that
produces haploid gametes Each gamete receives one member of each
pair of homologous chromosomes The first nuclear division, meiosis
I, separates the pairs of homologues, with each daughter nucleus
receiving one The second nuclear division, meiosis II, separates
the chromatids and parcels one chromatid into each of two more
daughter nuclei
Slide 23
Crossing over During prophase I, homologous chromosomes pair up
and exchange DNA Crossing over is a mutual exchange of
corresponding chromatid sections (and, therefore, DNA) between
maternal and paternal homologues The binding proteins and enzymes
then depart, leaving crosses or chiasmata (singular, chiasma),
where the maternal and paternal chromosomes have exchanged parts If
the exchanged segments carry different alleles, genetic
recombination has occurred
Slide 24
Table 9-1
Slide 25
Chapter 10 Inheritance Inheritance is the process by which the
traits of organisms are passed to their offspring A gene is a unit
of heredity that encodes information needed to produce proteins,
cells, and entire organisms The location of a gene on a chromosome
is called its locus (plural, loci) Alternative versions of genes
found at the same gene locus are called alleles
Slide 26
Alleles Each cell carries two alleles per characteristic, one
on each of the two homologous chromosomes If both homologous
chromosomes carry the same allele (gene form) at a given gene
locus, the organism is homozygous at that locus If two homologous
chromosomes carry different alleles at a given locus, the organism
is heterozygous at that locus (a hybrid)
Slide 27
Gregor Mendel Gregor Mendel, an Austrian monk, discovered the
common patterns of inheritance and many essential facts about
genes, alleles, and the distribution of alleles in gametes and
zygotes during sexual reproduction True-breeding organisms possess
traits that remain inherited unchanged by all offspring produced by
self-fertilization The pairs of alleles on homologous chromosomes
separate, or segregate, from each other during meiosis, which is
known as Mendels law of segregation
Slide 28
Genotype and Phenotype The particular combination of the two
alleles carried by an individual is called the genotype For
example, PP (homozygous) or Pp (heterozygous) The physical
expression of the genotype is known as the phenotype (for example,
purple or white flowers) A test cross is used to deduce whether an
organism with a dominant phenotype is homozygous for the dominant
allele or heterozygous
Slide 29
When the heterozygous phenotype is intermediate between the two
homozygous phenotypes, the pattern of inheritance is called
incomplete dominance A species may have multiple alleles for a
given characteristic The human blood types are an example of
multiple alleles of a single gene
Slide 30
Table 10-1
Slide 31
Polygenic Inheritance These traits are influenced by
interactions among two or more genes through a process called
polygenic inheritance Examples of this include height, skin color,
and body build in humans, and grain color in wheat According to
research, human height is controlled by at least 180 genes Human
skin color is controlled by at least three genes, each with pairs
of incompletely dominant alleles
Slide 32
Gene Linkage Genes on the same chromosome tend to be inherited
together, a phenomenon called gene linkage Crossing over creates
new combinations of linked alleles The farther apart two linked
gene loci are on a chromosome, the more likely crossing over is to
occur between them Crossing over, or genetic recombination, in
prophase I of meiosis creates new gene combinations
Slide 33
Sex-linked genes Genes carried on one sex chromosome, but not
on the other, are sex-linked In humans, the X chromosome is much
larger than the Y and carries over 1,000 genes In contrast, the
human Y chromosome is smaller and carries only 78 genes Color
blindness is caused by recessive alleles of either of two genes
located on the X chromosome
Slide 34
Genetic disorders An allele known as TYR (for tyrosinase)
encodes a defective tyrosinase protein in skin cells, producing no
melanin and a condition called albinism (recessive) Sickle-cell
anemia is caused by a defective allele for hemoglobin synthesis
(recessive) Huntington disease is a dominant disorder that causes a
slow, progressive deterioration of parts of the brain Several
defective alleles for characteristics encoded on the X chromosome
are known, including red-green color blindness and hemophilia
Slide 35
Non-disjunction The incorrect separation of chromosomes or
chromatids in meiosis is known as nondisjunction Nondisjunction
causes gametes to have too many and too few chromosomes Turners
syndrome (XO) occurs in females with only one X chromosome Trisomy
X (XXX) results in a fertile normal woman with an extra X
chromosome Men with Klinefelter syndrome (XXY) have an extra X
chromosome
Slide 36
Non-disjunction Embryos with three copies of an autosome
(trisomy) also usually spontaneously abort; however, a small
fraction of embryos with three copies of chromosomes 13, 18, or 21
survive to birth The frequency of nondisjunction increases with the
age of the parents In trisomy 21 (Down syndrome), afflicted
individuals have three copies of chromosome 21 Occurs in about 1
out of every 800 births
Slide 37
Chapter 11 -DNA Heritable information is carried in discrete
units called genes DNA is composed of four nucleotides DNA is made
of chains of small subunits called nucleotides Each nucleotide has
three components 1. A phosphate group 2. A deoxyribose sugar 3. One
of four nitrogen-containing bases 1. Thymine (T) 2. Cytosine (C) 3.
Adenine (A) 4. Guanine (G)
Slide 38
Chargaffs Rule In the 1940s Erwin Chargaff, a biochemist at
Columbia University, analyzed the amounts of the four bases in DNA
from diverse organisms He discovered a consistency in the equal
amounts of adenine and thymine, and equal amounts of guanine and
cytosine for a given species, although there was a difference in
proportion of the bases
Slide 39
Figure 11-5 The Watson-Crick model of DNA structure Hydrogen
bonds hold complementary base pairs together in DNA Two DNA strands
form a double helix Four turns of a DNA double helix nucleotide
free phosphate base (cytosine) sugar hydrogen bonds free sugar free
phosphate free sugar
Slide 40
Watson & Crick In 1953, James Watson and Francis Crick
consolidated all the historical data about DNA into an accurate
model of its structure Genetic information is encoded in the
sequence of nucleotides The key lies in the sequence, not the
number, of subunits
Slide 41
DNA replication Duplication of the parent cell DNA is called
DNA replication DNA replication produces two DNA double helices,
each with one original strand and one new strand The ingredients
for DNA replication are threefold The parental DNA strands Free
nucleotides A variety of enzymes that unwind the parental DNA
double helix and synthesize new DNA strands DNA Helicases, DNA
polymerases
Slide 42
DNA replication The two resulting DNA molecules have one old
parental strand and one new strand (semiconservative
replication)
Slide 43
Mutations Infrequent changes in the sequence of bases in DNA
result in defective genes called mutations Mutations may have
varying effects on function Mutations are often harmful, and an
organism inheriting them may quickly die Some mutations may have no
functional effect Some mutations may be beneficial and provide an
advantage to the organism in certain environments Point
(Substitution), deletion, insertion, translocation, inversion
Slide 44
Chapter 12 Gene expression DNA contains the molecular blueprint
of every cell Proteins are the construction workers of the cell
Proteins control cell shape, function, reproduction, and synthesis
of biomolecules DNA information must be carried by an intermediary,
ribonucleic acid (RNA), from the nucleus to the cytoplasm DNA in
eukaryotes is kept in the nucleus Protein synthesis occurs at
ribosomes in the cytoplasm
Slide 45
RNA RNA differs structurally from DNA in three ways 1. RNA is
usually single-stranded 2. RNA has the sugar ribose rather than
deoxyribose in its backbone 3. RNA contains the nitrogenous base
uracil (U) instead of thymine (T)
Slide 46
Types of RNA There are three types of RNA involved in protein
synthesis Messenger RNA (mRNA) carries DNA gene information to the
ribosome Transfer RNA (tRNA) brings amino acids to the ribosome
Ribosomal RNA (rRNA) is part of the structure of ribosomes
Slide 47
Figure 12-1 Cells synthesize three major types of RNA that are
required for protein synthesis codons Messenger RNA (mRNA)
catalytic site large subunit small subunit tRNA/amino acid binding
sites Ribosome: contains ribosomal RNA (rRNA) 12 tyr tRNA attached
amino acid Transfer RNA (tRNA) anticodon Each tRNA carries a
specific amino acid (in this example, tyrosine [tyr]) to a ribosome
during protein synthesis; the anticodon of tRNA pairs with a codon
of mRNA, ensuring that the correct amino acid is incorporated into
the protein rRNA combines with proteins to form ribosomes; the
small subunit binds mRNA; the large subunit binds tRNA and
catalyzes peptide bond formation between amino acids during protein
synthesis The base sequence of mRNA carries the information for the
amino acid sequence of a protein; groups of these bases, called
codons, specify the amino acids
Slide 48
Definitions Messenger RNA carries the code for protein
synthesis from DNA to the ribosomes Codons, groups of three bases
in mRNA, specify which amino acids will be incorporated into a
protein Ribosomes, the structures that carry out translation, are
composed of rRNA and many different proteins A group of three
bases, called an anticodon, protrudes from each tRNA
Slide 49
Transcription - Translation DNA directs protein synthesis in a
two-step process 1.Information in a DNA gene is copied into RNA in
the process of transcription Occurs in the nucleus of eukaryotic
cells 2.Messenger RNA, together with tRNA, amino acids, and a
ribosome, synthesizes a protein in the process of translation of
the genetic information contained in the mRNA Occurs in the
cytoplasm of eukaryotic cells
Slide 50
Genetic code The genetic code translates the sequence of bases
in nucleic acids into the sequence of amino acids in proteins DNA
and RNA contain four different bases adenine (A); thymine (T;
uracil {U} in RNA); guanine (G); and cytosine (C). Given that there
are 20 amino acids but only four bases, statistically, the smallest
number of bases that could combine to yield a different sequence
for each of the 20 amino acids is three A two-base code could
produce only 16 combinations The three-base code has the potential
to create 64 combinations
Slide 51
Transcription The three steps of transcription correspond to
the three major parts of most genes in eukaryotes and prokaryotes
1. A promoter region at the beginning of the gene marks where
transcription is to be initiated 2. The body of the gene
corresponds with where elongation of the RNA strand occurs 3. A
termination signal at the end of the gene marks where RNA synthesis
is to terminate
Slide 52
Introns and Exons Each gene consists of two or more segments of
DNA that encode for protein, called exons, that are interrupted by
other segments that are not translated, called introns Functions of
intron-exon gene structure Through alternative splicing of the
exons in a gene, a cell can make multiple proteins from a single
gene Alternative splicing represents an exception to Beadle and
Tatums one geneone protein relationship
Slide 53
Translation During translation, mRNA, tRNA, and ribosomes
cooperate to synthesize proteins Like transcription, translation
has three steps 1. Initiation 2. Elongation 3. Termination
Slide 54
Mutations affect protein synthesis The effects of mutations
depend on how they alter the codons of mRNA Mutations take many
forms and can affect protein function in many ways (ex. Sickle cell
anemia) Mutations fall into five categories 1. Inversions 2.
Translocations 3. Deletions 4. Insertions 5. Substitutions
Slide 55
Figure 12-10 An overview of information flow in a eukaryotic
cell Cells can control the frequency of transcription Different
mRNAs may be produced from a single gene Cells can control the
stability and rate of translation of particular mRNAs Cells can
regulate a proteins activity by modifying it Cells can regulate a
proteins activity by degrading it Degradation Modification
Translation mRNA tRNA amino acids inactive protein active protein
amino acids product substrate If the active protein is an enzyme,
it will catalyze a chemical reaction in the cell ribosomes
(cytosol) (nucleus) mRNA processing tRNApre-mRNArRNA proteins
Transcription DNA
Slide 56
Chapter 13 - Biotechnology Biotechnology is the use, and
especially the alteration, of organisms, cells, or biological
molecules to produce food, drugs, or other goods
Slide 57
Transformation Transformation may combine DNA from different
bacterial species In transformation, bacteria pick up pieces of DNA
from the environment This DNA could be part of a chromosome from
another bacterium or tiny circular DNA molecules called plasmids
Passing plasmids from bacteria to yeast may also occur, a process
that moves genes from prokaryotes to eukaryotes
Slide 58
PCR Developed by Kary Mullis of the Cetus Corporation, the
polymerase chain reaction (PCR) produces virtually unlimited copies
of a very small DNA sample PCR involves two major steps 1.Marking
the DNA segment to be copied 2.Running repetitive reactions to make
multiple copies
Slide 59
Figure 13-3 PCR copies a specific DNA sequence DNA segment to
be amplified original double- stranded DNA segment 194 F (90 C)122
F (50 C)158 F (70 C) primers DNA polymerase Heating separates DNA
strands Cooling allows primers and DNA polymerase to bind New DNA
strands are synthesized new DNA strands One PCR cycleEach PCR cycle
doubles the number of copies of the DNA PCR cycles DNA copies 12 21
4 4 etc. 16 etc. 8 3
Slide 60
STRs Forensic scientists have found that small, repeating
segments of DNA, called short tandem repeats (STRs), can be used
with astonishing accuracy to identify people STRs vary greatly
between different human individuals, like genetic fingerprints The
U.S. Department of Justice established a standard set of 13 STRs,
each four nucleotides long, to identify individuals by DNA
samples
Slide 61
Gel electrophoresis Gel electrophoresis separates DNA segments
Mixtures of DNA fragments can be separated on the basis of size Gel
electrophoresis is a technique used to spread out DNA fragments of
varying lengths in a mixture Because of its phosphates, the
negatively charged DNA moves toward the positive electrode, with
smaller fragments moving through the gel meshwork more quickly than
larger ones DNA probes are short, single-stranded DNA fragments
used to identify DNA in a gel pattern
Slide 62
GMOs Biotechnology can be used to identify, isolate, and modify
genes Combine genes from different organisms Move genes from one
species to another Using restriction enzymes, genes are inserted
into plasmids Each of the restriction enzymes cut DNA at a
specified nucleotide sequence
Slide 63
Transgenic Organisms Transfecting, which is inserting the gene
into the host organism and having it be expressed in the
appropriate cells, at the appropriate times, and at the desired
level, is difficult Transgenic animals can be engineered by
incorporating genes into chromosomes of a fertilized egg, which is
allowed to grow to term
Slide 64
DNA Technology DNA technology can be used to diagnose inherited
disorders Two methods are commonly used to find out if a person
carries a normal allele or a malfunctioning allele Restriction
enzymes may cut different alleles of a gene at different locations,
yielding distinctive fragments characteristic of one allele or the
other (sickle cell anemia) PCR can be used to isolate and amplify
disease-specific genes for various types of diagnostic procedures
DNA probing is especially useful where there are many different
alleles at a single gene locus
Slide 65
Chpt. 28 Energy flow in Ecosystems All ecosystems consist of
two components The biotic component of an ecosystem is the
community of living organismsbacteria, fungi, protists, plants, and
animalsin a given area The abiotic component of an ecosystem
consists of all nonliving physical or chemical aspects of the
environment, such as the climate, light, temperature, availability
of water, and minerals in the soil
Slide 66
Energy Energy, in contrast, takes a one-way journey through
ecosystems Solar energy is captured by photosynthetic bacteria,
algae, and plants, and then flows from organism to organism
Eventually, all of lifes energy is converted to heat that is given
off to the environment and cannot be used to drive the chemical
reactions of living organisms Life requires a continuous input of
energy
Slide 67
Trophic levels Each category of organisms is called a trophic
level Producers (or autotrophs) make their own food using inorganic
nutrients and solar energy from the environment Organisms that
cannot photosynthesize are called consumers (or heterotrophs)
Primary consumers feed directly and exclusively on producers These
herbivores include animals such as grasshoppers, mice, and zebras,
and form the second trophic level
Slide 68
Consumers Carnivores (meat eaters), such as spiders, hawks, and
salmon, make up the higher-level consumers Carnivores act as
secondary consumers when they prey on herbivores Some carnivores
eat other carnivores and are called tertiary consumers
Slide 69
Net Primary Production The energy that photosynthetic organisms
store and make available to other members of the community over a
given period is called net primary production Biomass, or dry
biological material, is usually a good measure of the energy stored
in organisms bodies
Slide 70
Food Web A food web shows many interconnected food chains, and
actual feeding relationships in a community Some animals, such as
raccoons, bears, rats, and humans, are omnivores (everything
eaters) and act as primary, secondary, and tertiary consumers Among
the most important strands in a food web are the detritivores
(debris eaters) and decomposers (fungi and bacteria)
Slide 71
Figure 28-5 An energy pyramid for a grassland ecosystem
tertiary consumer (1 calorie) secondary consumer (10 calories)
primary consumer (100 calories) producers (1,000 calories)
Slide 72
Biological Magnification If the food contains certain types of
toxic substances, they may be stored and become more concentrated
This biological magnification can lead to harmful and even fatal
effects Example DDT
Slide 73
Macronutrients Some of the chemical building blocks of life,
called macronutrients, are required by organisms in large
quantities Water Carbon Hydrogen Oxygen Nitrogen Phosphorous Sulfur
Calcium
Slide 74
Carbon cycle The carbon cycle is the pathway that carbon takes
from its major short-term reservoirs in the atmosphere and oceans,
through producers and into the bodies of consumers, detritivores,
and decomposers, and then back again to its reservoirs
Slide 75
Figure 28-7 The carbon cycle reservoirs processes trophic
levels CO 2 dissolved in the ocean CO 2 in the atmosphere burning
fossil fuels respirationfire consumers producers photosynthesis
fossil fuels (coal, oil, natural gas) detritivores and decomposers
decomposition
Slide 76
The Nitrogen Cycle The nitrogen cycle is the pathway taken by
nitrogen from its primary reservoirnitrogen gas (N 2 ) in the
atmosphereto much smaller reservoirs of ammonia and nitrate in soil
and water, through producers, consumers, detritivores and
decomposers, and back to its reservoirs
Slide 77
Figure 28-8 The nitrogen cycle reservoirs processes trophic
levels burning fossil fuels N 2 in the atmosphere lightning
application of manufactured fertilizer producers consumers
decomposition ammonia and nitrates in water denitrifying bacteria
detritivores and decomposers uptake by producers ammonia and
nitrates in soil nitrogen-fixing bacteria in soil and legume
roots
Slide 78
The phosphorus Cycle The phosphorus cycle is the pathway taken
by phosphorus from its primary reservoir in rocks to much smaller
reservoirs and back
Slide 79
Figure 28-9 The phosphorus cycle phosphate in rock reservoirs
processes trophic levels geological uplift application of
manufactured fertilizer runoff from rivers runoff from fertilized
fields phosphate in water uptake by producers producers consumers
detritivores and decomposers decomposition phosphate in soil
phosphate in sediment formation of phosphate-containing rock
Slide 80
Acid rain Burning of sulfur-containing fossil fuels, primarily
coal, accounts for about 75% of all sulfur dioxide emissions
worldwide These two substances combine with atmospheric water and
form nitric and sulfuric acids Acid deposition (acid rain) damages
forests, can render lakes lifeless, and even eats away at buildings
and statues. Since 1990, government regulations have resulted in
substantial reductions in emissions of both sulfur dioxide and
nitrogen oxides from U.S. power plants
Slide 81
Chapter 31 - Homeostasis Walter Cannon coined the term
homeostasis to describe the ability of an organism to maintain its
internal environment within narrow limits that allow optimal cell
functioning Although homeostasis (meaning to stay the same) implies
a static, unchanging state, the internal environment actually
seethes with activity as the body continuously adjusts to varying
internal and external conditions
Slide 82
Homeostasis The internal environment is maintained in a state
of dynamic constancy Homeostatic mechanisms regulate various
conditions Temperature Water and salt concentrations in body fluids
Glucose concentrations pH (acid-base balance) Hormone secretion
Oxygen and carbon dioxide concentrations
Slide 83
Feedback Systems Feedback systems regulate internal conditions
There are two types of feedback systems 1.Negative feedback
systems, which counteract the effects of changes in the internal
environment and are principally responsible for maintaining
homeostasis 2.Positive feedback systems, which drive rapid, self-
limiting changes, such as those that occur when a mother gives
birth
Slide 84
Negative Feedback The most important mechanism governing
homeostasis is negative feedback, in which a change causes
responses that counteract the change The overall result of negative
feedback is a return of the system to its original condition
Endothermic animals use negative feedback systems to maintain their
internal temperature despite fluctuations in the temperature around
them In humans and mammals, the temperature control center is
located in a part of the brain called the hypothalamus
Slide 85
Positive Feedback Positive feedback enhances the effects of
changes In positive feedback, a change produces a response that
intensifies the initial change Positive feedback is relatively rare
in biological systems, but occurs during childbirth The early
contractions of labor push the babys head against the cervix to
stretch and open The hypothalamus responds by triggering the
release of a hormone called oxytocin
Slide 86
Body Organization This coordination of complex body systems is
based on a simple hierarchy of structures cells tissues organs
organ systems Cells are the fundamental units of all living
organisms
Slide 87
Body Organization Animal tissues are composed of similar cells
that perform a specific function Organs are structures that perform
complex functions and include two or more interacting tissue types
Organ systems consist of two or more interacting organs that
function in a coordinated manner
Slide 88
Tissues There are four major categories of animal tissues 1.
Epithelial tissue - covers the body, lines its cavities, and forms
glands 2. Connective tissue - There are three main categories of
connective tissue 1. Loose connective tissue - consisting of a
thick fluid containing scattered cells that secrete protein 2.
Dense connective tissue- packed with collagen fibers - tendons and
cartilage 3. Specialized connective tissue cartilage, bone,
adipose, blood and lymph
Tissues 3. Muscle tissue has the ability to contract, smooth,
skeletal, and cardiac. Smooth and cardiac muscle contractions are
involuntary 4. Nerve tissue - makes up the brain, spinal cord, and
nerves in all body parts Nerve tissue is composed of two types of
cells 1. Nerve cells, also called neurons 2. Glial cells
Slide 91
Chapter 33 - Respiration Requirements for Gas Exchange
1.Respiratory surfaces remain moist, because cell membranes are
always moist, and only gases dissolved in water can diffuse into or
out of cells 2.Respiratory surfaces are very thin to minimize
diffusion distances 3. Respiratory surfaces have a sufficiently
large surface area in contact with the environment to allow
adequate gas exchange by diffusion to meet the needs of the
organism
Slide 92
Adaptations for Gas diffusion Some animals in moist
environments lack specialized respiratory structures For O 2
delivery to cells, some animals combine a large skin surface area
with a well-developed circulation (earthworm) Most relatively
large, active animals have respiratory systems that work as a unit
to facilitate gas exchange between the animal and its
environment
Slide 93
Lungs and gills Terrestrial vertebrates respire using lungs
Lungs are chambers containing moist respiratory surfaces that are
protected within the body, where water loss is minimized and the
body wall provides support Amphibians use gills for respiration as
aquatic larvae, and a simple, sac-like lung when they metamorphose
into the adult form
Slide 94
Respiratory system The respiratory system in humans and other
mammals can be divided into two parts 1.The conducting portion,
which consists of a series of passageways that carry air into and
out of the gas-exchange portion of the respiratory system 2.The
gas-exchange portion within the lungs, where oxygen and carbon
dioxide are exchanged through the blood - alveoli, the tiny air
sacs where gas exchange occurs
Slide 95
Breathing Breathing rate is controlled by the respiratory
center of the brain Unlike the heart muscle, the diaphragm and rib
muscles used in breathing are not self-activating Each contraction
causing inhalation is stimulated by impulses from nerve cells These
impulses originate in the respiratory center, which is located in
the medulla, a portion of the brain just above the spinal cord
Slide 96
Figure 33-10 Gas exchange between alveoli and capillaries to
the pulmonary vein from the pulmonary artery capillary walls
alveolar wall respiratory membrane surfactant fluid protein fibers
Oxygen diffuses into the red blood cells Carbon dioxide diffuses
into the alveolus (air)
Slide 97
Chapter 32 Circulatory System All circulatory systems have
three major parts 1.A pump, the heart, that keeps the blood
circulating 2.A liquid, blood, that serves as a medium of transport
for gases, nutrients, and cellular wastes 3.A system of tubes,
blood vessels, consisting of arteries that carry blood away from
the heart, veins that carry blood toward the heart, and capillaries
that link arteries and veins and exchange materials through their
walls
Slide 98
Open Circulatory System Open circulatory systems are found in
many invertebrates, including arthropods and mollusks These animals
have one or more simple hearts, some blood vessels, and a series of
interconnected spaces within the body called a hemocoel Tissues and
organs in the hemocoel are bathed in a fluid called hemolymph,
Slide 99
Closed Circulatory System Closed circulatory systems confine
the blood to the heart and to vessels that carry blood throughout
the body Blood pressure and flow rates are higher than is possible
in an open system A closed circulatory system is better able to
direct blood to specific tissues as needed
Slide 100
Closed circulatory system Closed circulatory systems are
present in all vertebrates (such as fishes, reptiles, and mammals)
and in a few invertebrates, including very active mollusks (squid
and octopuses) and, perhaps surprisingly, earthworms, where five
contractile vessels serve as hearts
Slide 101
Heart Structure The vertebrate heart consists of muscular
chambers capable of strong contractions Chambers called atria
collect blood Atrial contractions send blood into ventricles,
chambers whose contractions circulate blood through the lungs and
to the rest of the body The four-chambered heartwith its right
atrium and right ventricle completely isolated from its left atrium
and left ventricleacts like two hearts beating as one
Slide 102
Pulmonary Circuit The right heart deals with oxygen-poor blood
The right atrium receives oxygen-depleted blood from the body
through the two largest veins, the superior vena cava and the
inferior vena cava After filling with blood, the right atrium
contracts, forcing blood into the right ventricle Contraction of
the right ventricle sends the oxygen- poor blood to the lungs
through the pulmonary arteries
Slide 103
The left heart The left heart deals with oxygenated blood
Oxygen-rich blood from the lungs enters the left atrium through the
pulmonary veins and is then squeezed into the left ventricle A
strong contraction of the left ventricle, the hearts most muscular
chamber, sends the oxygenated blood coursing out through the
largest artery, the aorta, and then to the rest of our body
Slide 104
Blood components Blood, sometimes called the river of life, has
two major components 1.A liquid, called plasma, which comprises
about 55% to 60% of the blood volume 2.A cell-based portion
consisting of red blood cells, white blood cells, and platelets
suspended in the plasma
Slide 105
Table 32-1 Blood Components and Their Functions, 2 of 2
Slide 106
Red Blood Cells About 99% of all blood cells, and about 45% of
the total blood volume, are oxygen-carrying red blood cells, also
called erythrocytes The red color of erythrocytes is caused by the
large, iron-containing protein hemoglobin, which transports oxygen
in the blood The red blood cell count is maintained by a negative
feedback system that involves the hormone erythropoietin.
Erythropoietin stimulates the rapid production of new red blood
cells by the bone marrow
Slide 107
Capillaries Blood leaving the heart travels from arteries to
arterioles to capillaries, then into venules, and finally, to
veins, which return it to the heart Capillaries allow individual
body cells to exchange nutrients and wastes with the blood by
diffusion Capillaries are so narrow that red blood cells pass
through them single file
Slide 108
The lymphatic system The lymphatic system includes some organs,
as well as an extensive system of lymphatic vessels, which
eventually feeds into the circulatory system This organ system
performs the following functions: Returns excess extracellular
fluid and plasm to the bloodstream Transports fats from the small
intestine to the bloodstream Filters aged blood cells and other
debris from the blood Defends the body by exposing bacteria and
viruses to white blood cells
Slide 109
Chapter 34 Digestion Nutrients are substances obtained from the
environment that organisms need for their growth and survival
Nutrients fall into six major categories 1. Carbohydrates 2. Lipids
3. Proteins 4. Minerals 5. Vitamins 6. Water
Slide 110
Food sources of energy Nutrients that supply energy are lipids,
carbohydrates, and proteins Carbohydrates are a source of quick
energy Fats and oils are the most concentrated energy source Fats
and oils contain over twice as many Calories per unit weight as do
carbohydrates or proteins
Slide 111
Essential Nutrients Our cells can synthesize most of the
molecules our bodies require, but they cannot synthesize certain
raw materials, called essential nutrients, which must be supplied
in the diet Essential nutrients for humans include certain fatty
acids and amino acids, a variety of minerals and vitamins, and
water
Slide 112
Minerals Minerals are elements required by the body Minerals
are elements that play many crucial roles in animal nutrition and
can only be obtained in the diet or dissolved in drinking water
Calcium, magnesium, and phosphorus are major constituents of bone
and teeth Sodium, calcium, and potassium are needed for muscle
contraction and the conduction of nerve impulses
Slide 113
Vitamins Vitamins play many roles in metabolism Vitamins are
organic molecules that animals require in small amounts for normal
cell function, growth, and development Human vitamins are grouped
into two categories: water soluble or fat soluble
Slide 114
Table 34-3, 2 of 2
Slide 115
Digestive Systems All digestive systems perform five tasks 1.
Ingestion: Food is brought into the digestive tract through an
opening, usually called a mouth 2.Mechanical digestion: The food is
physically broken down into smaller pieces that have a greater
surface area than do larger particles, allowing digestive enzymes
to attack them more efficiently 3.Chemical digestion: Digestive
chemicals and enzymes break down large food molecules into smaller
subunits
Slide 116
Digestive Systems 4. Absorption: The small subunits are
transported out of the digestive tract through cells lining the
digestive tract to the blood for use by body cells 5.Elimination:
Indigestible materials are expelled from body All animals except
sponges have evolved a chamber within the body in which chunks of
food are broken down by enzymes outside the cells, a process called
extracellular digestion.
Slide 117
Figure 34-12 The human digestive tract Large intestine: Absorbs
vitamins, minerals, and water; houses bacteria, produces feces
Gallbladder: Stores bile from the liver Liver: Secretes bile(also
has many non-digestive functions) Esophagus: Transports food to the
stomach Pharynx: Shared digestive and respiratory passage Salivary
glands: Secrete lubricating fluid and starch-digesting enzymes Oral
cavity, tongue,teeth: Grind food, mix with saliva Epiglottis:
Directs food down the esophagus Stomach: Breaks down food and
begins protein digestion Pancreas: Secretes bicarbonate and several
digestive enzymes Small intestine: Food is digested and absorbed
Rectum: Stores feces
Slide 118
Chemical Digestion Most chemical digestion and nutrient
absorption occurs in the small intestine The small intestine is a
long, narrow tube that receives chyme from the stomach, completes
digestion of food molecules in the chyme, and absorbs these smaller
nutrient molecules into the body