BIOL 214 Exam 1 Prep Lecture 1

Gene

A specific sequence of nucleotides in a DNA molecule coding for a protein or trait.

Human Chromosome Count

46 individual chromosomes arranged in 23 homologous pairs (diploid, 2n).

Protein-Coding DNA Percentage

Less than 2% of the human genome consists of protein-coding genes.

Human Karyotype Composition

22 pairs of autosomes and 1 pair of sex chromosomes.

Mendel's Law of Segregation

Allele pairs separate during gamete formation, so each gamete carries only one allele per gene.

Mendel's Law of Independent Assortment

Alleles of different genes assort independently of one another during gamete formation.

Allele

An alternate version or variation of a specific gene. (A&a)

Codominance

Inheritance pattern where two dominant alleles both affect the phenotype in distinct, separate ways.

Incomplete Dominance

Inheritance pattern where the F1 hybrid phenotype is an intermediate mix of parental phenotypes. (3 phenotypes usually seen)

Pleiotropy

A single gene affecting multiple distinct phenotypic traits. (huntingtons disease)

Polygenic Inheritance

Multiple independent genes collectively determining a single phenotypic trait. (human height)

Epistasis

Phenomena where one gene alters or masks the phenotypic expression of a second gene. (flashlight on but being covered)

Multifactorial Inheritance

Traits influenced by the combination of multiple genes and environmental factors.

Ecology Definition

The scientific study of interactions determining the distribution and abundance of organisms. (determined by interactions between organism & its biotic/abiotic environment)

Organismal Ecology

Subfield focusing on physiological and behavioral interactions between individual organisms and environment.

Population Ecology

Subfield studying the dynamics and genetics of a single species group over time.

Community Ecology

Subfield studying interactions among coexisting groups of different species.

Ecosystem Ecology

Subfield studying interactions between biological communities and their non-living (abiotic) environment.

Emergent (or "Novel") Properties

New properties arising at higher organizational levels from interactions among lower-level components. (ex: neurons that compile the brain)

Ecological Network Nodes and Links

Nodes represent individual species; links represent pairwise ecological interactions between them.

Scientific Hypothesis Requirement

A valid scientific hypothesis must be both testable and falsifiable.

Evolution (Genetic Definition)

A change in allele frequencies within a population over successive generations.

Natural Selection

when one allele makes an organism more or less fit in terms of survivability and reproductive output in a given environment

Genetic Drift

Random fluctuations in allele frequencies due to chance events, affecting smaller populations most. sharply influenced by bottleneck effects from natural disasters and founder effect after a split from a source pop

Bottleneck Effect

A sharp reduction in population size and genetic diversity caused by a random disaster.

Founder Effect

Genetic drift occurring when a small isolated group establishes a new population.

Gene Flow

The movement of alleles into or out of a population through migration. (can be individuals or gametes), prevents isolation and speciation

Assortative Mating

Non-random mating preference for individuals with similar phenotypes or genotypes.

lethal alleles

shorten life expectancy

Quantitative Inheritance

Region of DNA / 1+ genes that contribute to variation in a measurable trait (height or weight)

ecosphere/biosphere

sum of all earths ecosystems

Earths Fundamental Trait

High degree of organization

mutations

any change to DNA sequence and the ultimate source of genetic variation (deleterious, neutral, or advantageous). can be spontaneous or induced by mutagens (like sun, bacteria, etc), change the frequencies in a population

non-random mating

everyone has the same chance to reproduce (all alleles must have the same probability of entering the next generation). 3 ways to occur with assortive, disassortive, and consanguineous

assortive mating

preference for mates with similar genotypes/phenotypes

disassortive mating

preference for mates with different genotypes/phenotypes

consanguineous mating

inbreeding, "within blood", preference for mates who are closely related

What is a phylogenetic tree?

A diagram showing evolutionary relationships/common ancestry among organisms.

What does a branch point/node on a phylogenetic tree represent?

A common ancestor where lineages diverged.

What does it mean if two organisms share a more recent common ancestor?

They are more closely related evolutionarily.

What is DNA's basic structure?

Double-stranded nucleic acid made of nucleotides containing a sugar, phosphate, and nitrogenous base.

What are the four bases in DNA?

A, T, C, G

What are the four bases in RNA?

A, U, C, G

DNA base-pairing rules

A-T and C-G

RNA base-pairing rules

A-U and C-G

Major difference between DNA and RNA

DNA is generally double-stranded and uses thymine; RNA is generally single-stranded and uses uracil.

Central dogma / protein synthesis

DNA → RNA → Protein

Transcription

DNA → RNA

Translation

RNA → protein

Four major biological macromolecules

Carbohydrates, lipids, proteins, nucleic acids

Monomer of proteins

Amino acids

Monomer of nucleic acids

Nucleotides

Basic building blocks of carbohydrates

Monosaccharides/simple sugars

What type of reaction joins monomers to form larger molecules?

Dehydration/condensation reaction

What type of reaction breaks polymers apart?

Hydrolysis

Characteristics shared by living things

Organization, metabolism/energy use, homeostasis, growth/development, reproduction, response to environment, and capacity for evolution.

Element

Substance consisting of one type of atom.

Molecule

Two or more atoms chemically bonded together.

Isotope

Atoms of the same element with different numbers of neutrons.

Radioisotope

An unstable isotope that undergoes radioactive decay.

Half-life

Time required for half of a radioactive sample to decay.