Biology Final Exam Review

Evolution

Change in allele frequency over time.

Natural Selection

A process where individuals with higher fitness (reproductive success) reproduce more, leading to changes in allele frequencies.

Population

A group of organisms of the same species living in the same area.

Fitness

Reproductive success of an individual, measured by the number of offspring produced.

Mutation

Random changes to the DNA sequence that may or may not affect the organism.

Genetic Drift

Random changes in allele frequency, typically in small populations.

Founder Effect

A change in allele frequencies that occurs when a small group starts a new population.

Bottleneck

A significant reduction in population size, which reduces genetic variation.

Gene Flow

The movement of alleles between populations due to migration.

Central Nervous System

Composed of the brain and spinal cord; responsible for integration of information.

Peripheral Nervous System

The part of the nervous system that receives sensory information and sends responses.

Neuron

A nerve cell that transmits signals in the nervous system.

Dendrites

Extensions of a neuron that receive impulses.

Axon

The part of a neuron that sends signals away from the cell.

Synapse

The junction between two neurons or a neuron and a muscle.

Action Potential

An electrical impulse that travels down the axon of a neuron.

Resting Potential

The voltage difference across a neuron's membrane when it is not actively transmitting signals.

Sodium-Potassium Pump

A mechanism that actively transports sodium out and potassium into the cell to maintain resting potential.

Synaptic Transmission

The process by which neurotransmitters are released from one neuron to activate another.

Neurotransmitter

Chemical messengers that transmit signals across the synapse.

Acetylcholine

A neurotransmitter involved in muscle stimulation and transmission of signals in the nervous system.

Hypothesis

A testable and falsifiable statement.

Independent variable

The variable that goes on the x-axis in a graph.

Prokaryotic domains

Bacteria and Archaea.

Eukarya

Domain that includes multicellular organisms.

Chloroplasts

Organelle responsible for photosynthesis in plant cells.

Cell wall

Rigid layer providing structural support in plant cells.

Large central vacuole

Large plant cell organelle for storage and maintaining turgor pressure.

Centrioles

Cytoplasmic structures involved in organizing spindle fibers during cell division.

Lysosomes

Organelle containing digestive enzymes.

Mitochondria

Produces ATP, the cell's energy currency.

Selective permeability

Plasma membrane allows some substances in/out but not others.

Genotype

Genetic makeup.

Phenotype

Physical traits.

RNA polymerase

Enzyme that carries out transcription.

Silent mutation

A DNA change that does not alter the amino acid (synonymous codon).

Diploid

Having two sets of chromosomes; typically somatic cells.

Haploid

Having one set of chromosomes; gametes.

Crossing over

Process during meiosis I that increases genetic diversity.

Autosomes

Non-sex chromosomes.

Sex chromosomes

X and Y chromosomes that determine sex.

Mitosis

Produces two identical diploid cells.

Meiosis

Produces four unique haploid gametes.

Red-green colorblindness

An X-linked recessive trait.

Hemophilia

An X-linked recessive trait.

Codominance

A pattern where both alleles are expressed in the phenotype; e.g., blood type AB.

Mutations

A source of genetic diversity.

Independent assortment

Random orientation of chromosomes during meiosis, increasing diversity.

Spleen

Produces, stores, & releases white blood cells

Bone marrow

Where most blood cells are produced

Lymph vessels

Circulates lymph & cleans interstitial fluids (fluid around cell tissues)

Lymphatic system

Moves white blood cells, attacks pathogens directly OR by poison

Lymph fluid

Clear fluid that carries immune cells & fights infection

Innate Defenses

1st line of defense, ex: skin and mucous membranes, broad and diverse defense, immediate response

Adaptive Immune System

develops over time, targets specific pathogens by memory cells and antibodies (B & T Cells)

Macrophages

attacks bacteria & digests it, first responder

Neutrophils

casts toxic dna w/ chemicals to kill bacteria by exploding, can cause damage to healthy cells

Complement Proteins

enhances antibodies, acts w/ fluid to kill bacteria

B & T Cells

recognize specific pathogens & multiples, uses memory cells, floods body w/ antibodies to kill specific pathogens, B cells produce antibodies, T cells destroy bacteria

Antigens

provoke immune response

Antigen Receptors

molecules on B and T cells that recognize specific antigens and initiate an immune response.

Antibodies

proteins produced by B cells that bind to specific antigens to neutralize pathogens or mark for destruction

Cytotoxic-T Cells

cell-mediated immunity, binds to suspicious cells, releases toxic chemical to kill infected cells

Clonal Selection

produces B cells by cloning and stays identical 

Population

group of species living in same environment

Habitat

area where a population lives

Population Density

the number of individuals per unit area or volume in a habitat.

Population Distribution

the way in which individuals are spread across a given area, can be uniform, clumped, or random

Birth Rate

number of individuals produced per time unit

Immigration

number of individuals moving into a population per time unit

Death Rate

number of individuals that die per time unit

Emigration

number of individuals leaving a population per time unit

Photons

Packets of light energy

Population Exponential Growth

when resources are unlimited, shows as a J-shaped curve

Population logistic growth

Growth slows as population reaches habitats carrying capacity, S-shaped curve

Density-dependent factors

Increase as pop density rises, results from interaction between organisms. EX: predation, disease, starvation

Density-independent factors

Exert effects that are unrelated to pop density. EX: natural disaster, habitat destruction

Heterotrophs

Get carbon atoms from eating organisms (ex. humans)

Autotrophs

Get carbon from environment (ex. plants)

Pigments

Molecules that capture energy from light

Photosynthesis

Turning solar energy into chemical energy

Mesophyll cells

Completes photosynthesis in leaf of plant

Calvin cycle

Happens in stoma, makes sugar

Light-dependent reactions

Happens in grana/chloroplast, Uses water & light, makes oxygen

Chemiosmotic Phosphorylation

Turns ADP into ATP