Science GHSGT ReviewBiology

What is Biology?

• The study of living things• What is considered living?

•anything that has the ability to nourish, grow, and reproduce

•cells must be present

Cell Theory

• The cell is considered the basic unit of life.

• All living things contain at least one cell.

• Cells come from pre-existing cells.

Plant Cell versus Animal Cell

Plant Cell Animal Cell

Plant Cell versus Animal Cell

Plant Cell• oblong/square-like

shape• cell wall (provides

structure)• chloroplast (location of

photosynthesis/ energy production)

Animal Cell• round/circular shape• centrioles (responsible

for cell reproduction)

Cell Organelles

STRUCTURE FUNCTION

nucleus control of all cell activities; location of DNA

mitochondria energy production

Golgi complex (apparatus)

assembles, sorts, and transports cell products

ribosome protein synthesis

chromosome composed of DNA containing genetic material

Cell Organelles (continued)

STRUCTURE FUNCTION

cell membrane

phospholipid bilayer; maintains homeostasis; protects the cell

lysosome digests old cells and food (cleans up the cell)

endoplasmic reticulum

produces, stores, and transports protein (rough) and lipids (smooth)

flagella/cilia movement of materials

Prokaryotes versus Eukaryotes

Prokaryotes• “Pro-No”• No true nucleus• No membrane-bound

organelles• No well-organized

membrane• All prokaryotes are

bacteria (Monera)

Eukaryotes• “Eu-True”• True nucleus• Well organized

membrane• Membrane – bound

organelles• Most plants and

animals and other specialized organisms

Active versus Passive Transport

Active Transport• requires energy (low

concentration to high)• endocytosis and

exocytosis• active transport (ATP

is used)

Passive Transport• diffusion (particles

from high concentration to low)

• osmosis (water from high concentration to low)

• facilitated transport (diffusion using a membrane protein)

Organic CompoundsORGANIC

COMPOUND DEFINITION FUNCTION

carbohydrates sugars and starches provide energy

lipids fats (insoluble in water) store energy

proteins amino acidsresponsible for

most cell functions

nucleic acids DNA and RNA store hereditary information

Cell Membrane and Homeostasis• Homeostasis = The maintenance of a constant,

stable environment internally (ex: body temperature)

• Cell membrane utilizes active and passive transport• diffusion and osmosis depends on environment

(hydrophobic or hydrophilic)

Hydrophilic versus Hydrophobic

Hydrophilic• “water-loving”• inside of cell

Hydrophobic• “water-fearing”• outside of cell

Hypertonic versus Hypotonic

HypOtonic• Higher concentration

of water outside the cell

• Cell swells when placed in hypotonic solution

Hypertonic• Higher concentration

of water inside cell• Cell shrinks when

placed in hypertonic solution

Isotonic• Equal concentrations of

water inside and outside of cell

Genetics• The study of the inheritance of traits and how

genes pass on these traits from parents to offspring

• Mendel is the Father of Genetics (studied pea plants)

Important Genetics Vocabulary• trait: a characteristic of an organism that is

inherited (examples: eye color, hair type, etc.) • gene: basic unit of heredity made of DNA that

determines the characteristics of a trait• allele: the two different versions of a gene for a

particular trait (one received from each parent)

Genotype versus Phenotype

Genotype• an organism’s genetic

makeup• includes the two

alleles• represented with two

letters (example: Bb)

Phenotype• the physical

appearance of a trait• expressed by the

organisms genes• represented by

description (example: brown eyes)

Dominant versus Recessive

Dominant• an allele that

expresses itself while hiding the effects of another allele

• represented with a capital letter

• example: Bb (dominant brown eyes dominates over recessive blue)

Recessive• An allele whose effects

are hidden by a dominant allele

• Represented with a lower-case letter

• example: Bb (dominant brown eyes dominates over recessive blue)

Probability and Punnett Squares• Probability is the likelihood an event will occur• Geneticists use Punnett squares to predict the

probability of genetic combinations• Example: When two heterozygous brown eyes

mate . . .

B b

B BB Bb

b Bb bb

Theory of Inheritance• Chromosomes are the physical basis of

inheritance (carry DNA).• Variability results from dominant and recessive

alleles.• The chromosomes in the male gamete and female

gamete join together during fertilization to form a zygote.

• gamete = sex cell• zygote = fertilized egg

DNA• deoxyribonucleic acid• found in chromosomes in the nucleus• determines the hereditary traits of an organism• contains all the information needed for the

production of proteins• protein sequences determine traits

RNA• ribose nucleic acid• aids in protein synthesis in the ribosome• 3 types:

• messenger RNA: mRNA carries the DNA nucleotide sequence for a protein from the nucleus to the ribosome

• transfer RNA: tRNA transports amino acids (building blocks of proteins) to the ribosome

• ribosomal RNA: rRNA makes up the structure of the ribosome

DNA Replication• self-duplication of the genetic material• results in two new DNA molecules• occurs during interphase (just before cell divides)• proteins unwind the DNA helix and each strand

acts as a template for a new strand• unbound nucleotides attach . . .

• A-T (adenine binds with thymine)• C-G (cytosine binds with guanine)

DNA Transcription• to “transcribe” is to copy• mRNA is synthesized in the cell nucleus from the

DNA molecule• Just as in replication, the helix unwinds and free

nucleotides attach to make mRNA. . . • C-G (cytosine binds with guanine)• U-A (uracil binds with adenine)• Only DNA has thymine

• mRNA separates and moves out of the nucleus• DNA double helix reforms

DNA Translation• process of translating the genetic code to the

amino acid sequence• tRNA decodes the mRNA to read the DNA in order

to make the correct protein

Mutations• A mutation is any change in the DNA sequence.• A change in one nucleotide may cause a change

in the structure of the protein.• During pregnancy, observing a karyotype (a

chromosome picture) can detect chromosomal defects.

Taxonomy• The study of the classification of organisms

Classification• Kingdom• Phylum• Class• Order• Family• Genus• Species

• King• Phillip• Cried • Out • For• Good• Soup

Binomial Nomenclature• Classification system used to give all organisms a

two-part name• First name = Genus name• Second name = Species name• Example:

• scientific name of a wolf is Canis lupus

Kingdom Monera• bacteria• need water, nutrients, and a moderate

temperature to survive• autotrophs (make their own food) and

heterotrophs (obtain food from outside source)• decomposers (AKA saprophytes) = break down

dead organisms to release carbon and nitrogen• reproduce asexually (binary fission)• some possess flagella used for motion

Kingdom Protista• algae, seaweed, protozoans, water (slime) molds• found in aquatic or damp environments• organisms that don’t fit in any other kingdom• autotrophs (algae) and heterotrophs (protozoans)• reproduce either asexually or sexually• some have flagella or cilia for motion• gave rise to all other eukaryotic organisms

Kingdom Fungi• mushrooms, yeast, molds, mildews, rusts• all are heterotrophs (do not contain chlorophyll)• absorb food from environment• many are saprophytes (decomposers) that obtain

nutrients from dead or decaying plants and animals

• reproduce either asexually or sexually

Kingdom Plantae• autotrophs (utilize photosynthesis)• Two groups:

• bryophytes (nonvascular) have no roots, stems, or leaves and transport nutrients using diffusion (examples: mosses, liverworts, hornworts)

• tracheophytes (vascular) have roots, stems, and leaves that transport water and nutrients throughout the plant (examples: ferns, gymnosperms, and angiosperms)

• all reproduce both sexually and asexually (alternation of generations)

Kingdom Animalia• worms, insects, sponges, birds, mammals• all are heterotrophs that have a digestive cavity in

which food is digested and absorbed• all reproduce sexually, but some (like jellyfish) can

also reproduce asexually

Unicellular versus Multicellular

Unicellular• single-celled• composed of one cell• all bacteria and

protists• non-specialized cells

Multicellular• multi-celled• composed of many

cells• all other organisms

(fungi, plants, & animals)

• cells are specialized to perform different functions

Asexual versus Sexual Reproduction

Asexual• involves only one parent• no specialized sex cells

are produced• does not undergo meiosis• chromosomes are

duplicated in mitosis• Examples:

• binary fission = cell simply splits

• budding = offspring grows out of the side of the parent

• involves two parents so genetic diversity is increased

• specialized male and female sex cells (gametes) are produced

• gametes fuse during fertilization to produce a zygote (fertilized egg)

• gametes are formed in meiosis

• chromosomes are duplicated in mitosis

Haploid versus Diploid

Haploid• sex cells• contain one of each

chromosome• human haploid cells

have 23 chromosomes

Diploid• all non-sex cells• contain 2 copies of

each chromosome• human diploid number

is 46 (two sets of 23 – a set from each parent)

Mitosis• begins after interphase = cell growth,

chromosome (DNA)replication, and prep for division (most of a cell’s life cycle is spent in interphase)

• results in two identical daughter cells containing same number of chromosomes and genetic information as the parent cell

Phases of Mitosis1. Prophase = chromosomes become visible

(present), nucleus membrane disappears, and in animal cells, centrioles move to opposite sides of the cell

2. Metaphase = chromosomes line up in the middle of the cell

3. Anaphase = chromosomes move toward opposite poles of the cell (move away)

4. Telophase = chromosome become less distinct and nucleus membrane reappears; nucleus divides into two (cytokinesis)

Cytokinesis• occurs after telophase• cytoplasm divides forming two separate cells

Phases of Mitosis

Meiosis• cell division that results in the formation of

haploid gamete cells (sex cells)• Meiosis I

• reduction division• diploid cell divides creating two haploid cells

• Meiosis II• two haploid cells from meiosis I divide resulting in 4 haploid daughter cells

Mitosis versus Meiosis

Mitosis• resulting cells have

same number and kind of chromosomes as parent cell

• used for cell growth, tissue repair, and asexual reproduction

Meiosis• resulting cells have

half the number of chromosomes as parent cell

• used for gamete formation

Ecology• The study of interactions among organisms and

between organisms and their environment

Biomes• Biome = a large area characterized by a certain

climate and types of plants and animals• 6 major biomes on Earth

Biome CharacteristicsName Characteristics

Tundra permanently frozen subsoil

Taigalong severe winters;

summers with thawing subsoil

Temperate Forest moderate precipitation; cold winters; warm summers

Tropical Forest heavy rainfall; constant warmth

Grassland variability in rainfall and temperature; strong winds

Desert sparse rainfall; extreme daily temperature fluctuations

Biomes of the Earth

Ecosystem Vocabulary• Ecosystem = a part of the environment with its

organisms, their interactions, and the physical and chemical factors that affect them

• Community = populations of different species that interact in an ecosystem

• Population = all the individuals of the same species living in a community

Members of an Ecosystem• Producers = organisms that can make their own

food; autotrophs; examples: bacteria, protists, plants

• Consumers = organisms that eat other organisms to get energy; heterotrophs; examples: fungi and animals

Consumer Classification• Herbivore = primary consumer who only eats

plants; example: cow• Carnivore = secondary consumer who only eats

other animals; examples: shark and tiger• Omnivore = consumer that eats both plants and

animals; example: most humans• Scavengers = animals that find dead plants or

animals and eat them; examples: flies, wasps, cockroaches, earthworms

• Decomposers = break down dead organisms to receive energy; examples: fungi and bacteria

Predator versus Prey• All animals must eat to survive. Animals can be

either predators or prey.• Predators hunt prey.• With predators always on the lookout for a meal,

prey must constantly avoid being eaten. • Any adaptation the prey uses adds to the chances

of survival for the species.• Some adaptations are defense mechanisms which

can give the prey an advantage against enemies.

Survival Defense Mechanisms• speed

• You can’t eat what you can’t catch!• physical or chemical features

• physical examples: quills on a porcupine or hard shell of a turtle

• chemical examples: stink of a skunk; poisons of a dart frog

• camouflage • allows the animal to blend in with its environment to avoid

being detected• used by both predators and prey

Parasite versus Host• A parasite is an animal or plant that lives in or on

a host (another animal or plant)• Parasites obtain nourishment from the host

without benefiting or killing the host• Examples: canine heartworms, malaria,

hookworms, pinworms, tapeworm

Food Chain• a diagram that

shows the way energy is transferred from one organism to another

• each step in a food chain is called a trophic level

• begins with producers and ends with decomposers

Food Web• complex,

interconnecting food chains in a community

• more accurate than food chain

Pyramids of Biomass/Energy