ICC Biology Final

Gene

Segment of DNA coding for trait

Allele

Different version of gene

Genotype

Genetic makeup

Phenotype

Physical appearance

Dominant

Expressed with one copy

Recessive

Requires two copies

Homozygous

Two same alleles

Heterozygous

Two different alleles

Replication

Copying DNA

Transcription

DNA → mRNA

Translation

mRNA → protein

Codon

3-base mRNA sequence

Anticodon

Complementary tRNA sequence

Ribosome

Site of protein synthesis

Law of segregation

Alleles separate

Independent Assortment

Genes assort independently unless linked

Incomplete Dominance

Blended alleles

Codominance

Both visable

Linked Genes

Genes located close together on same chromosome

Crossing Over

Exchange of chromosome segments during meiosis. Purpose to increase genetic variation.

DNA Replicaiton

Purpose is to copy DNA before cell division and occurs in S phase of interphase.

Semiconservative replication

Each new DNA molecule contains one old strand and one new strand

Helicase

Enzyme that unwinds DNA

DNA polymerase

Enzyme that adds complementary nucleotides during replication

DNA function

Stores genetic information

mRNA

Functions is to carry genetic code from DNA to ribosome

tRNA

function to bring amino acids to ribosome

Ribosome

Functions as site of protein synthesis

Transcription

Process of making mRNA from DNA. Product mRNA (in nucleus)

Translation

process of making protein from DNA. Product being protein/ polypeptide (in Ribosomes)

Universal genetic code

Same codons code for same amino acids in nearly all organisms

Transgenic organism

Organism containing genes from another species

GMO

Genetically modified organism

Cloning

Producing genetically identical copies

Gene Cloning

Copying specific genes

Reproductive Cloning

Creating entire genetically identical organism

Therapeutic Cloning

Producing stem cells for research and treatment

DNA Fingerprinting

Identifying individuals using DNA patterns

STRs

Short tandem repeats used in DNA fingerprinting

PCR

Polymerase chain reaction. Purpose is to make many copies of DNA. doubles DNA amount 2n.

Descent with modification

Species change over time form common ancesters

Natural Selection

(Charles Darwin) Individuals with advantageous traits survive and reproduce more.

Variation

Differences among individuals in population

Overproduction

More offspring produced than can survive

Homologous structures

SImilar anatomy due to common ancestry

Embryological homology

Similar embryos suggest common ancestry

Fossil Record

Preserved remains showing evolutionary history

Genetic Drift

Random change in allele frequencies

Bottleneck effect

Population drastically reduced by chance event

Founder effect

Small group starts new population

Directional selection

Favors one extreme phenotype

Stabilizing selection

Favors average phenotype

Disruptive selection

Favors both extreme phenotypes

Sexual dimorphism

Physical differences between males and females

Sexual Selection

Selection based on mating sucess

Gene Flow

Movement of alleles between populations. It increases genetic diversity and keeps populations similar.

Geographic isolation

Physical barriers separate populations

Behavioral isolation

Different mating behaviors prevent reproduction

Temporal isolation

Different breeding times prevent reproduction

Mechanical isolation

Reproductive structures incompatible

Genetic isolation

Gametes cannot fuse

Homologous sturctures

Same ancestry, different functions

Analogous structures

Same function, different ancestry

Divergent evolution

Related species become increasingly different

Convergent evolution

Unrelated species evolve similar traits

Binomial nomenclature

Two-part scientific naming system