DNA, Cell Division, and Evolution Concepts

DNA

Genetic material with instructions for traits.

gene

A segment of DNA that codes for a protein.

nucleotide

Sugar, phosphate, nitrogen base.

complementary

A pairs with T, C pairs with G.

transcription

DNA is copied into mRNA.

translation

mRNA is used to build proteins.

mRNA

Messenger RNA; carries code to ribosome.

tRNA

Transfer RNA; brings amino acids.

codon

3 bases on mRNA that code for 1 amino acid.

anticodon

3 bases on tRNA that match the codon.

mutation

A change in DNA.

point mutation

One base is changed.

frameshift mutation

Bases are added or deleted, shifting the reading frame.

differentiation

Cells becoming specialized.

mitosis

Cell division that makes 2 identical cells.

meiosis

Cell division that makes 4 unique sex cells.

chromosome

DNA wrapped around proteins.

sister chromatid

Two identical halves of a duplicated chromosome.

stages of mitosis

Prophase, Metaphase, Anaphase, Telophase.

interphase

The cell grows and copies DNA.

cytokinesis

The cell splits in two after mitosis.

diploid cell

A cell with a full set of chromosomes (body cell).

haploid cell

A cell with half the chromosomes (sex cell).

gamete

A sex cell (egg or sperm).

somatic cell

A body cell.

genotype

The genetic makeup (BB, Bb, bb).

phenotype

The trait you see (brown eyes).

dominant allele

Shows even if only one is present (B).

recessive allele

Only shows if both are present (bb).

homozygous

Two of the same alleles (BB or bb).

heterozygous

Two different alleles (Bb).

Punnett square

A chart that shows possible offspring traits.

Law of Segregation

Alleles separate during meiosis.

Law of Dominance

One allele can mask another.

pedigree

A family tree that shows inherited traits.

natural selection

The process where better traits help organisms survive and reproduce.

selective pressure

Anything that affects survival (like predators or climate).

adaptation

A helpful trait that improves survival.

evolution

Change in a population over time.

fossil

Preserved remains of past life.

fossil record

Collection of all known fossils.

homologous structures

Similar bones, different use (like arm of human and wing of bat).

analogous structures

Same use, different structure (like bird wing and insect wing).

vestigial structures

Leftover parts with little use (like human tailbone).

phylogenetic tree

A diagram that shows evolutionary relationships.

common ancestor

A species that two or more species came from.