Biology facts and study sheet

7/29/2019 Biology facts and study sheet

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ProteinsDNA-Double helix, sugar phosphate

backbone

Adenine-Thymine,

Guanine-Cytosine

Thymine and Cytosine-Pyrimidine

Guanine and Adenine-Purine

Pyrimidines and Purines-5 sugar

carbon, phosphate group, nitric base

RNA-One helix, ribose instead of

dextrose, RNA polymerase starts

without primer

mRNA-messenger RNA, codes for

protein

tRNA-central to protein synthesis as

adaptors between mRNA and aminoacids

rRNA= ribosomal RNA

form the basic structure of the

ribosome and catalyze protein

synthesis

Transcription- the synthesis of RNA

under DNA (occurs in the nucleus)

Translation- the actual synthesis of a

polypeptide coded for by the mRNA.

(changing the base sequence of the

mRNA molecule into a chain of aminoacids that form a polypeptide. For our

purposes a protein.)

An mRNA copy is made from DNA in

the Nucleus

The DNA strand from which the

mRNA is copied is the TEMPLATE

STRAND

The mRNA leaves the nucleus and

enters a ribosome (made up of rRNA)

tRNA collects a specific amino acids

present in the cell and brings it to theribosome

The anticodon of the tRNA matches up

with its counterpart codon on the

mRNA

When the mRNA & the tRNA link up

the amino acid detaches and is

connected to the adjacent amino acid

EPA-mRNA enters A site

When the first codon reaches the P

site the tRNA brings down the amino

acid and links up with the mRNA

The E site is where the amino acid

separates form the tRNA and links upto adjacent amino acids. This is where

the MRNA and tRNA leave the

ribosome

Anticodons specify which amino acid a

tRNA collects

The anticodon then pairs up with its

corresponding codon

The anticodon AGU would pair with

the codon UCA.

THEY ARE OPPOSITES OF EACH

OTHERCodon

This basic unit of genetic code is 3

nucleotides long

It specifies a specific amino acid

Each codon only specifies 1 amino

acid (BUTan amino acid may have

several different codons that code for

it)

Mitosis, Meosis

Interphase-What the cell spends 90%of its time doing.

Divided into G1,S, and G2 stages

This is where the cell goes about basic

life functions of growth, DNA copying

and regulation

G1-During this stage new organelles

are being synthesised, so the cell

requires both structural proteins and

enzymes, resulting in great amount of

protein synthesis.

In short the cell grows (Growthphase)

S-synthesis phase, is a period when

DNA synthesis or replication occurs.

G2-Cell grows more and prepares to

divide

Mitosis-(The M phase)
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Before We Split

mitosis= the division of a cell's

nucleus. Along with cytokinesis (the

division of the rest of a cell), mitosis

results in a parent cell dividing into

two daughter cells. The geneticinformation within each of these

daughter cells is identical.

Interphase-The nucleus rep;icates its

DNA and centrosome

Interphase-prophase transition-The

chromatin begins to coil

Prophase-The chromatin continues to

coil and supercoil, making the

chromarin more and more compact.

The chromosomes consist of identical,

paired chromatidsPrometaphase-The nuclear envelope

breaks down. Kinetochore

microtubules appear and interact with

polar microtubes of the spindle,

resulting in movement of the

chromosomes

Metaphase-The duplicated

centromere regions connecting paired

chromatids become aligned in a plane

at the cells equator

Anaphase-Each centromere divides,and the new chromosomes (each

derived from one member of one of

the sets of paired chromatids) begin to

move toward poles

Telophase-The separating

chromosomes reach the poles.

Telophase passes into the next inter

phase as the nuclear envelopes and

nucleoi re-form and the chromatin

becomes diffuse

Cytokinesis is the process of splittingthe daughter cells apart.

Whereas mitosis is the division of the

nucleus, cytokinesis is the splitting of

the cytoplasm and allocation of the

golgi, plastids and cytoplasm into each

new cell.

Meiosis

Interphase-The nucleus replicates its

DNA and centrosomes

Interphase-prophase transition-The

chromatin begins to coil

Prophase I-Homologous

chromosomes pair up (each made upof 2 sister chromatids)

Homologous chromosomes swap

some allele information

Nuclear envelope disappears

Metaphase I-Chromosomes line up

down the middle

Spindle fibers attach

Anaphase I-1 of each of the

Homologous chromosomes is pulled

to each side of the cell

Telophase I & Cytokinesis-The celldivides down the middle

Nuclear envelope sometimes reforms

No New Interphase

Prophase II-Spindle fibers form

Nuclear envelope disintegrates

Metaphase II-Chromosomes line up in

the center of the cell, spindle fibers

attach

Anaphase II-Sister chromatids

separate

Telophase II & Cytokinesis-Nucleusreforms, not that each of the four cells

is haploid

Homologous chromosomes swap

information in meiosis

In meiosis 1 homologous

chromosomes not sister chromatids

are separated

Meiosis ends with 4 daughter cells,

Mitosis ends in 2

ChemistryAtomic Theory-All matter (living andnon-living) found on Earth is

composed of atoms.

Atom: Smallest particle an element

can be divided into.

Parts of the Atom:

Proton: positive charge, in nucleus.


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Neutron: no charge, in nucleus.

Electron: negative charge, around the

nucleus.

Atom-Is now defined as the smallest

particle of an element that retains the

chemical properties of that elementElement-A pure substance or material

composed of only one type of atom.

The periodic table is broken down

into vertical column called groups or

families numbered from left to right

(1-18) and

horizontal rows called periods

numbered from top to bottom (1-7)

For the most part you can divide the

periodic table into two main parts,

Metals and Non-metals.Metals-Metals are located of the left

side of the table and make up

approximately 88% of all elements.

Are generally good conductors of both

heat and electricity.

Most are solids as well as malleable

and ductile.

Nonmetals-Are located on the right

side of the periodic table and

comprise approximately 12% of all

elements.Are poor conductors of electricity and

heat, tend to be brittle, and are often

(though not always) found as gases in

nature.

Metalloids-Are elements that have

some characteristics of metals and

also some non-metal characteristics.

They are located along the stair step

line on the right side of the periodic

table. All are solids, are less malleable

than metals but not as brittle as non-metals. Tend to be semi-conductors of

electricity.

Noble Gases-Found in group 18 of the

periodic table. Generally un-reactive.

Gases at room temperature.

Molecule:

Atoms make up molecules.

Two or more atoms bonded together.

One type of atom (ex: O2)

Two or more types of atoms (ex: H2O)

Compound:

Atoms make up compounds.

Two or more elements bondedtogether.

Two or more types of atoms (ex: H2O)

Atomic Number-The number of

Protons in the nucleus of an atom of a

particular element.

Atomic Mass-The number of Protons +

the number of Neutrons in the nucleus

of an atom of a particular element.

Isotopes-Atoms of the same element

(the same number of protons) with

different numbers of neutrons. Theyhave identical atomic numbers but

different mass numbers.

Electron Energy Levels-Within the

electron cloud, electrons are arranged

in energy levels. Electrons in each

energy level have a specific amount of

energy. Each energy level can only

hold a specific number of electrons.

Combinations-Few elements exist as

independent particles, most

substances are made up ofcombinations of atoms held

Octet Rule-The outer valence shell can

hold a maximum of 8 electrons

Achieving the maximum number of e-

in this valence shell results in a stable

content atom.

Chemical Bond-A mutual electrical

attraction between the nuclei and

valence electrons of different atoms

Why Atoms Bond to Other Atoms-

Most atoms are less stable existing bythemselves (they are at a relatively

high potential energy). Nature favors

arrangements in which potential

energy is minimized. Bonding creates

more stable arrangements of matter in

lower potential energy states.


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Valence electrons are redistributed.

Two main types: Covalent and Ionic

Electrical attraction between cations

and anions. Due to gain or loss of

electrons (also called electron

transfer) between atoms.Ions-An ion is an atom or group of

atoms with one or more net positive

or negative electrical charges.

The number of positive or negative

charges on an ion is shown as a

superscript after the symbol for an

atom or group of atoms

-Hydrogen ions (H+), Hydroxide ions

(OH-)

Sodium ions (Na+), Chloride ions (Cl-)

Electron Dot Notation -An electronconfiguration notation in which only

the valence electrons of an atom of a

particular element are shown,

indicated by dots placed around the

elements symbol.

Genetic InheritanceGregor Mendel

The first person to trace the

characteristics of successive

generations of a living thingHe was not a world-renowned

scientist of his day.

Rather, he was an Augustinian monk

who taught natural science to high

school students.

Second child of Anton and Rosine

Mendel

They were farmers in Brunn

They couldnt afford for him to attend

college

Gregor Mendel then attended theAugustinian Monastery and became a

monk

He was later sent to the University of

Vienna to study. By both his

professors at University and his

colleagues at the monastery, Mendel

was inspired to study variance in

plants

Mendel's attraction to research was

based on his love of nature.

He was not only interested in plants,

but also in meteorology and theoriesof evolution.

Mendel often wondered how plants

obtained atypical characteristics.

On a walk around the monastery, he

found an atypical variety of an

ornamental plant.

He took it and planted it next to the

typical variety.

He grew their progeny side by side to

see if there would be any

approximation of the traits passed onto the next generation.

This experiment was "designed to

support or to illustrate Lamarck's

views concerning the influence of

environment upon plants.

He found that the plants' respective

offspring retained the essential traits

of the parents, and therefore were not

influenced by the environment.

Once he crossed peas and mice of

different varieties "for the fun of thething," and the phenomena of

dominance and segregation "forced

themselves upon notice."

He saw that the traits were inherited

in certain numerical ratios.

He then came up with the idea of

dominance and segregation of genes

and set out to test it in peas.

It took seven years to cross and score

the plants to the thousand to prove

the laws of inheritance!The impact of genetic theory is no

longer questioned in anyone's mind.

Many diseases are known to be

inherited

and pedigrees are typically traced to

determine the probability of passing

along an hereditary disease.


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Plants are now designed in

laboratories to exhibit desired

characteristics.

The practical results of Mendel's

research has not only changed the

way we perceive the world, but alsothe way we live in it.

Took seven years to prove laws of

inheritance

-Basic Laws-

Heredity Factors do not combine

Each member of a parental generation

transfers only one half of its heredity

factors to each offspring

Mendels works became the

foundation of modern genetics

Later crossed mice and pea plantsNoticed traits were inherited in

certain numerical ratios

Came up with idea of dominance and

segregation of genes and set out to

test it in peas

Love of nature encouraged his interest

in research

Also interested in meteorology and

theories of evolution

Genetics-study of heredity

Heredity: the transmission of traitsfrom one generation to the next

Gene-A discrete unit of hereditary

information consisting of a specific

nucleic sequence in DNA (or RNA in

some viruses)

Locus-a genes specific location on a

chromosome ( the plural is loci)

Homologous Chromosomes: alike

chromosomes carrying genes for the

same heritable characteristics

Allele: an alternate form of a geneIe. One coding for blue eyes and one

for brown

Centromere-The joining point of 2

sister chromatids

telomere: the protective structure at

the end of the chromosome (protects

DNA when it is copied)

Sister Chromatids-Replicated forms of

a chromosome jointed together by the

centromere and eventually separated

by mitosis or meiosis 2

Character: a feature that can be

inherited by offspring from a parent(i.e. blue eyes)

Trait: a variation of a character

I.e. blue or green brown eyes are traits

What Mendel Did-He tooktrue

breeding pea plants

Meaning the parents only produced

offspring with the same combination

of traits that they had.

This is called monohybridization or

a monohybrid cross

The crossing of a single traitThe parents generation is the P

generation

The first generation of offspring is the

F1generation

The second generation of offspring is

the F2generation

Mendels Laws-

1. the Law of Dominance-In a cross

of parents that are pure for

contrasting traits, only one form of the

trait will appear in the nextgeneration. Offspring that are hybrid

for a trait will have only the dominant

trait in the phenotype.

A dominant trait will mask or cover up

a recessive trait

A recessive trait is only seen if the

offspring receive a copy of it from

each parent

A Dominant trait is expressed as a

capital letter i.e. A

A Recessive trait is expressed as alowercase letter i.e. a

2. the Law of Segregation

During the formation of gametes (eggs

or sperm), the two alleles responsible

for a trait separate from each other.

Alleles for a trait are then

"recombined" at fertilization,


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producing the genotype for the traits

of the offspring.

3. the Law of Independent

Assortment

Alleles for differenttraits are

distributed to sex cells (& offspring)independently of one another.

In other words the traits can be in any

combinations in offspring it doesn't

have to be all from the mother or all

from the father.

Homozygous : having identical alleles

for the same character AA or aa

Heterozygous: having 2 different

alleles for the same character

AaGenotype: what the genetic code

of the organism isPhenotype: what is actually expressed

(seen)

Expressed traits: the phenotype what

is seen

dihybrid cross: comparing two traits

simultaneously

Incomplete dominance- a blending of

characters. No dominant or recessive

This definition of evolution was

developed largely as a result ofindependent work in the early 20th

century by Godfrey Hardy, an English

mathematician, and Wilhelm

Weinberg, a German physician.

Through mathematical modeling

based on probability, they concluded

in 1908 that gene pool frequencies are

inherently stable but that evolution

should be expected in all populations

virtually all of the time. They resolved

this apparent paradox by analyzingthe net effects of potential

evolutionary mechanisms

They originally wrote it in a

restaurant ton a napkin after a

conversation about the topic

The 7 conditions need to use the

equation

1. mutationis not occurring

2. natural selectionis not occurring

3. the population is infinitely large

4. all members of the populationbreed

5. all mating is totallyrandom

6. everyone produces the same

number of offspring

7. there is no migration in or out of

the population

used to discover the probable

genotypefrequencies in a population

and to track their changes from one

generation to another

Hardy-Weinberg Equation-(p2 + 2pq+q2=1)

Diffusion, Osmosis

and Cell MembraneTransmission electron micrograph

showing a prostate cancer cell

immediately after exposure to

ultrasound. The image has been color

enhanced to show the spot where the

cell membrane has been removed.A membrane is a collage of different

proteins embedded in the fluid matrix

of the lipid bilayer

Diffusion is a process where molecules

move from greater molecule

concentrations to areas of less

molecule concentrations until an

equal distribution of those molecules

is reached.

Passive transport is diffusion across a

membrane-Movements of individualmolecules are random.

However, movement of a population

of molecules may be directional

For example, if we start with a

permeable membrane separating a

solution with dye molecules from pure
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water, dye molecules will cross the

barrier randomly.

The dye will cross the membrane until

both solutions have equal

concentrations of the dye.

At this dynamic equilibrium as manymolecules pass one way as cross the

other direction

For example, if we start with a

permeable membrane separating a

solution with dye molecules from pure

water, dye molecules will cross the

barrier randomly.

The dye will cross the membrane until

both solutions have equal

concentrations of the dye.

At this dynamic equilibrium as manymolecules pass one way as cross the

other direction. In the absence of

other forces, a substance will diffuse

from where it is more concentrated to

where it is less concentrated, down its

concentration gradient.

This spontaneous process decreases

free energy and increases entropy by

creating a randomized mixture.

Each substance diffuses down its own

concentration gradient, independentof the concentration gradients of other

substances.

The diffusion of a substance across a

biological membrane is passive

transportbecause it requires no

energy from the cell to make it

happen.

The concentration gradient

represents potential energy and

drives diffusion.

However, because membranes areselectively permeable, the interactions

of the molecules with the membrane

play a role in the diffusion rate.

Diffusion of molecules with limited

permeability through the lipid bilayer

may be assisted by transport proteins

The plasma membrane functions as a

selective barrier that allows passage

of oxygen, nutrients, and wastes for

the whole volume of the cell

All living matter is made up of cells. A

single human being has as many as the

stars in a galaxy, about one hundredthousand million.

Through pioneering discoveries

concerning the water and ion channels

of cells, this years Nobel Laureates

Peter Agre and Roderick MacKinnon,

have contributed to fundamental

chemical knowledge on how cells

function. They have opened our eyes

to a fantastic family of molecular

machines: channels, gates and valves

all of which are needed for the cell tofunction.

Osmosis is defined as the diffusion of

water across a selectively permeable

membrane

Differences in the relative

concentration of dissolved materials

in two solutions can lead to the

movement of ions from one to the

other.

The solution with the higher

concentration of solutes ishypertonic.

The solution with the lower

concentration of solutes is hypotonic.

These are comparative terms.

Tap water is hypertonic compared to

distilled water but hypotonic when

compared to sea water.

Solutions with equal solute

concentrations are isotonic.

Imagine that two sugar solutions

differing in concentration areseparated by a membrane that will

allow water through, but not sugar.

The hypertonic solution has a lower

water concentration than the

hypotonic solution.

More of the water molecules in the

hypertonic solution are bound up in


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hydration shells around the sugar

molecules, leaving fewer unbound

water molecules

Unbound water molecules will move

from the hypotonic solution where

they are abundant to the hypertonicsolution where they are rarer.

This diffusion of water across a

selectively permeable membrane is a

special case of passive transport called

osmosis.

Osmosis continues

until the solutions

are isotonic.

The direction of osmosis is

determined only by a difference in

totalsolute concentration.The kinds of solutes in the solutions

do not matter.

This makes sense because the total

solute concentration is an indicator of

the abundance of bound water

molecules (and therefore of free water

molecules).

When two solutions are isotonic,

water molecules move at equal rates

from one to the other, with no net

osmosisAn animal cell immersed in an isotonic

environment experiences no net

movement of water across its plasma

membrane.

Water flows across the membrane,

but at the same rate in both directions.

The volume of the cell is stable

For a cell living in an isotonic

environment (for example, many

marine invertebrates) osmosis is not a

problem.Similarly, the cells of most land

animals are bathed in an extracellular

fluid that is isotonic to the cells.

Organisms without rigid walls have

osmotic problems in either a

hypertonic or hypotonic environment

and must have adaptations for

osmoregulation to maintain their

internal environment

Turgid cells contribute to the

mechanical support of the plant.

If a cell and its surroundings are

isotonic, there is no movement ofwater into the cell and the cell is

flaccid and the plant may wilt

In a hypertonic solution, a cell wall

has no advantages.

As the plant cell loses water, its

volume shrinks.

Eventually, the plasma membrane

pulls away from the wall.

This plasmolysis

is usually

lethal.

DNAT.H. Morgans group showed that

genes are located on chromosomes,

the two constituents of chromosomes

- proteins and DNA - were the

candidates for the genetic material.

Until the 1940s, the great

heterogeneity and specificity of

function of proteins seemed to

indicate that proteins were the geneticmaterial.

However, this was not consistent with

experiments with microorganisms,

like bacteria and viruses

The discovery of the genetic role of

DNA began with research by Frederick

Griffith in 1928.

He studied Streptococcuspneumoniae,

a bacterium that causes pneumonia in

mammals.

One strain, the R strain, washarmless.

The other strain, the S strain, was

pathogenic.

In an experiment Griffith mixed heat-

killed S strain with live R strain

bacteria and injected this into a

mouse.


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The mouse died and he recovered the

pathogenic strain from the mouses

blood

Griffith called this phenomenon

transformation, a change in genotype

and phenotype due to the assimilationof a foreign substance (now known to

be DNA) by a cell.

In 1952, Alfred Hershey and Martha

Chase showed that DNA was the

genetic material of the phage T2.

The T2 phage, consisting almost

entirely of DNA and protein, attacks

Escherichiacoli (E. coli), a common

intestinal bacteria of mammals.

This phage can quickly

turn an E. coli cell intoa T2-producing factory

that releases phages

when the cell ruptures

By the beginnings of the 1950s, the

race was on to move from the

structure of a single DNA strand to the

three-dimensional structure of DNA.

Among the scientists working on the

problem were Linus Pauling, in

California, and Maurice Wilkins and

Rosalind Franklin, in LondonMaurice Wilkins and Rosalind

Franklin used X-ray crystallography to

study the structure of DNA.

In this technique, X-rays are

diffracted as they passed through

aligned fibers of purified DNA.

The diffraction pattern can be used

to deduce the three-dimensional

shape of molecules.

James Watson learned

from their researchthat DNA was helical

in shape and he deduced

the width of the helix

and the spacing of bases

Watson and his colleague Francis

Crick began to work on a model of

DNA with two strands, the double

helix.

Using molecular models made of wire,

they first tried to place the sugar-

phosphate chains on the inside.

However, this did not fit the X-raymeasurements and other information

on the chemistry of DNA

The key breakthrough came when

Watson put the sugar-phosphate chain

on the outside and the nitrogen bases

on the inside of the double helix.

The sugar-phosphate chains of each

strand are like the side ropes of a rope

ladder.

Pairs of nitrogen bases, one from

each strand, form rungs.The ladder forms a twist every ten

bases

DNA is often called the blueprint of

life.

In simple terms, DNA contains the

instructions for making proteins

within the cell

We study DNA for many reasons, e.g.,

its central importance to all life on

Earth,

medical benefits such as cures fordiseases,

better food crops

Our genes are on our chromosomes.

Chromosomes are made up of a

chemical called DNA

DNA is a very long polymer.

The basic shape is like a twisted

ladder or zipper.

This is called a double helix

The DNA double helix has two strands

twisted togetherThe backbone of the molecule is

alternating phosphate and

deoxyribose, a sugar, parts.

The teeth are nitrogenous bases.

The phosphate group of one

nucleotide is attached to the sugar

of the next nucleotide in line.


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The result is a backbone of

alternating phosphates and sugars,

from which the bases project

One strand of DNA is a polymer of

nucleotides.One strand of DNA has many millions

of nucleotides

Pyrimidines are single ring bases.

Purines are double ring bases

Thymine and cytosine each have one

ring of carbon and nitrogen atoms.

Adenine and guanine each have two

rings of carbon and nitrogen atoms.

Remember, DNA has two strands that

fit together something like a zipper.

The teeth are the nitrogenous basesbut why do they stick together?

The bases attract each other because

of hydrogen bonds.

Hydrogen bonds are weak but there

are millions and millions of them in a

single molecule of DNA.

(The bonds between cytosine and

guanine are shown here.)

When making hydrogen bonds,

cytosine always pairs up with guanine,

And adenine always pairs up withthymine

Each cell has about 2 m of DNA.

The average human has 75 trillion

cells.

The average human has enough DNA

to go from the earth to the sun more

than 400 times.

DNA has a diameter of only

0.000000002 m

DNA copy's in a very specific order. It

copies 5-3 from a 3-5 TemplateDNA needs the enzyme polymerase to

copy.

It cant begin replication on its own.

DNA helicase separates the two DNA

strands by breaking the hydrogen

bonds between them

This generates positive supercoiling

ahead of each replication fork

DNA gyrase travels ahead of the

helicase and alleviates these

supercoils

Single-strand binding proteins bind tothe separated DNA strands to keep

them apart

Then short (10 to 12 nucleotides) RNA

primers are synthesized by DNA

primase

These short RNA strands start, or

prime, DNA synthesis

If this problem is not solved

The linear chromosome becomes

progressively shorter with each round

of DNA replicationThe cell solves this problem by adding

DNA sequences to the ends of

chromosome: telomeres

Small repeated sequences (100-

1000s)

Catalyzed by the enzyme telomerase

Telomerase contains protein and RNA

The RNA functions as the template

complementary to the DNA sequence

found in the telomeric repeat

This allows the telomerase to bind tothe 3 overhang


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