BIOLOGY IS CONTAGIOUS

116 THINGS YOU NEED TO

KNOW TO PASS THE MCAS

BIOLOGY EXAM

Living things are mostly made of

the elements C,H,O,N,P, and S

Organic compounds contain carbon

Four important macromolecules are

carbohydrates, lipids, proteins,

and nucleic acids

Polymers are long chains of monomers

The monomer of a protein is an amino

acids

The monomer of a nucleic acid is a

nucleotide

A nucleotide consists of a sugar, a phosphate group, and a nitrogenous

base

The function of a carbohydrate is to provide a cell with

energy

Lipids store energy and are a

component of cell membranes and are

used to produce hormones

Proteins have a variety of functions in the cell and make

up muscles, hair, and nails

Nucleic acids store genetic information

for cells

Enzymes are proteins that speed

up chemical reactions (also

known as catalysts)

In a chemical reaction, reactants combine/change to

form products

Substrates fit into the active site of an enzyme like a “lock

in a key”

A substrate is a reactant in an

enzyme-catalyzed reaction

Enzymes work by lowering the

activation energy of a chemical reaction

Two things that affect enzyme function are

temperature and the pH(acid/base) of

a solution

Organelles are the parts of a cell

Prokaryotes do not have a nucleus; eukaryotes do

Plant cells contain cell walls, large vacuoles, and chloroplasts

Animal cells lack a cell well, never have

chloroplasts, and contain centrioles

DNA is found within the nucleus in a eukaryotic cell

Mitochondria produce energy (ATP) for cells

Chloroplasts are green and capture sunlight energy to

make sugar (glucose) for cells

The endoplasmic reticulum and the Golgi bodies work together to modify and ship proteins

Ribosomes are the site of protein

synthesis

The cytoskeleton gives the cell shape

and structure

The cell wall of a plant is made of a

carbohydrate (cellulose) and gives

plant their rigid shape

Cell membranes are found in all cells and

are made of a semi-permeable

lipid bilayer

Pump and channel proteins are also found in the cell

membrane

Active transport uses energy (ATP) to move molecules

from low concentration

to high conc.

Active transport requires protein

pumps

Facilitated diffusion uses protein

channels to move molecules from high

conc. to low conc.

Diffusion moves small molecules

through a membrane from high conc. to low

conc.

Osmosis is the diffusion of water

molecules through a semi-permeable

membrane

Photosynthesis: 6H2O +6CO2 + light C6H12O6 +6O2

(occurs in chloroplast)

Cellular Respiration: C6H12O6 +6O2 6H2O +6CO2 + ATP

(occurs in mitochondria)

Energy in a molecule of ATP is stored in the bonds between phosphate

groups

The stages of cell division (mitosis)

are prophase, metaphase,

anaphase, and telophase

Cytokinesis causes a cell to divide in two. Animal cells pinch,

plant cells assemble membrane and wall

Gametes (sperm/egg) are

made through a two rounds of reductive

division called meiosis

After mitosis, there is an equal number of chromosomes in each cell (diploid)

After meiosis, there is half the normal

amount of chromosomes in

each cell (haploid)

Fertilization is when sperm cells and egg cells join together

Crossing over in meiosis helps

increase genetic variation in offspring

DNA stores protein instruction in a

sequence of nitrogenous bases

called a gene

The sugar-phosphate

backbone gives the DNA molecule

structure

DNA is a double stranded molecule with a deoxyribose

sugar

A pairs with T and U ; G pairs with C

RNA is a single stranded molecule with a ribose sugar

RNA contains U instead of T

Three types of RNA: messenger,

ribosomal, and transfer

Replication is when DNA makes an

exact copy of itself

Transcription is when a gene is

copied onto mRNA

Translation is when the mRNA transcript

is used to make a polypeptide (protein)

Mutations can alter a DNA sequence, sometimes (not

always) causing a change in the

protein

The phenotype is what an organism

physically looks like

The genotype is what copies of a

gene an organism has

Alleles are different versions of a gene

Dominant alleles mask recessive

alleles

A heterozygous individual has two different alleles

A homozygous individual has two of

the same alleles

Blended phenotypes (red + white = pink) show that the alleles

are incompletely dominant

Mixed phenotypes (orange + blue = orange and blue) show codominant

alleles

Polygenic traits are controlled by more than one gene and

show a normal (bell) distribution

Evolution is change over long periods of

time

Natural selection states that the best adapted individuals will survive and pass

on their genes

Evidence for evolution is shown

in fossils, DNA sequences,

embryology, and homology

Genetic variation among organism

comes from crossing over and mutations

Speciation occurs when gene pools

become separated over long periods of

time

Organisms are classified by the

kingdom, phylum, class, order, family,

genus, species system

All organisms are descended with changes from an ancient, common

ancestor

Polygenic distribution curves

can undergo stabilizing,

disruptive, or directional selection

The three domains are eukarya, archea,

and bacteria

The six kingdoms are archeabacteria,

eubacteria, animalia, plantae,

fungi, protista

Evolutionary relationships are

based on DNA sequences NOT

physical appearance

The deeper in a rock layer a fossil is

found, the older that fossil is.

Population size is affected by birth

rates, death rates, and migration rates.

Limiting factors dictate the size of a

population

Carrying capacity is the maximum

number of individuals an ecosystem can

support

Ecological organization:

species – population – community –

ecosystem – biome - biosphere

Producers are autotrophs – they

make their own food

Consumers are heterotrophs – they

eat their food

A food web shows all of the feeding relationships in a

particular ecosystem

Energy arrows always flow from

the producers to the consumers

Only 10% of the available energy is transferred to the next trophic level

Herbivores are primary consumers

The main source of energy for living things is the sun

Carbon enters the biosphere through

photosynthesis

Carbon is returned to the atmosphere

by breathing (respiration) and the

burning of fossil fuels

Bacteria fix nitrogen gas into a form usable by living

organisms (nitrogen fixation)

Parasitic relationships involve

one organism benefiting and the

other organism suffering

Mutual relationships show a benefit for both organisms

Commensalism shows a benefit for one organism, and

no effect for the other

Homeostasis works via feedback loops

and maintains a constant internal

environment

Carbohydrates, fat, and protein are all

important sources of energy and nutrition

The stomach and mouth digest (break

down) food into smaller molecules

using enzymes

Nutrients are absorbed into the blood by the small

intestines

The kidneys filter waste materials out

of the blood

Blood is a suspension of red blood cells, white

blood cells, plasma, and platelets

Red blood cells carry oxygen, white

blood cells fight infection, and

platelets clot blood

The heart pumps blood throughout

the body

Veins carry blood to the heart (low oxygen) and

arteries carry blood to the body (high

oxygen)

Lungs contain tiny sacs called alveoli

Oxygen diffuses into the blood and carbon dioxide

diffuses out of the blood at the alveoli

Air enters the lungs via the trachea

(windpipe)

The bolus (mashed food and saliva)

enters the stomach via the esophagus

The nervous system allows the body to communicate and

coordinate functions

Neurons consist of a long axon, several

short dendrites, and a cell body

The endocrine system sends

chemical signals (hormones)

throughout the body

Muscles allow the body to move

There are three types of muscle: skeletal, smooth,

and cardiac

Red blood cells are made in bones

Bones provide structure and a site for mineral storage

Viruses are made of a protein coat and genetic material

(DNA/RNA). They are not alive!

Nerve use electrical impulses and

chemical (neurotransmitters)

to communicate