MCAS Review Topic 7: DNA and Genetics

Vocabulary flashcards for DNA and Genetics review.

DNA

Deoxyribonucleic acid; makes up chromosomes in the nucleus of eukaryotic cells.

Chromosome

A coiled piece of DNA.

Genes

Segments of DNA that code for traits.

Double Helix

The shape of DNA, resembling a twisted ladder.

Nucleotides

Building blocks of DNA, containing a deoxyribose sugar, a phosphate group, and a nitrogen-containing base.

Chargaff's Rules

Adenine (A) pairs with Thymine (T), and Cytosine (C) pairs with Guanine (G).

DNA Replication

A process where DNA copies itself, resulting in two new molecules each containing one old and one new strand.

Protein Synthesis

A process of making proteins in cells.

Transcription

DNA in the nucleus is copied using messenger RNA (mRNA).

Translation

Code on mRNA in ribosome is used to make protein.

Alleles

Different forms of a trait; humans have two alleles for every trait.

Dominant Allele

The stronger form of a trait that shows up in the organism; represented by a capital letter.

Recessive Allele

The weaker form of a trait; is normally hidden and only shows when the dominant allele is not present; represented by a lowercase letter.

Genotype

The genes of an organism.

Homozygous (purebred)

When 2 alleles for a trait are alike (same capitalization).

Heterozygous (hybrid)

When 2 alleles for a trait are different.

Phenotype

The physical appearance of an organism.

Punnett Squares

Charts used to show the possible gene combinations in offspring from a cross between two organisms; shows probability.

Codominance

When both alleles of a gene are expressed in a heterozygote.

Incomplete Dominance

When both alleles blend together in a heterozygote.

Sex-linked Trait

A recessive trait on an X chromosome.

Multiple Alleles

3 or more alleles that exist for a single gene.