TEAS: Describe the Relationship Between Genetic Material and the Structure of Proteins

Describe a chromosome? What is it’s function (2)?

Coiled DNA wrapped around histones; condenses DNA and regulates genes

What is the difference between prokaryotic and eukaryotic chromosomes?

Prokaryotes have one circular chromosome; eukaryotes have many linear ones

How many chromosomes do humans have? How many pairs?

46; 23

What is a gene? (2)

A segment of DNA that codes for a protein or regulates one

How big (how many bases) and how many genes do humans have?

A few hundred to 1 million + bases each; about 25,000 genes total.

What is a structural gene?

A gene that codes for proteins that build structures.

What is a regulatory gene?

A gene that turns other genes on or off.

Why don't all cells express the same genes?

Regulatory genes turn off unneeded genes (e.g., only skin cells express keratin)

What is DNA? (describe it’s shape, what it carries, what it does)

double helix, carries genetic code, and directs protein synthesis.

What makes up the DNA backbone? (2)

Phosphate and deoxyribose sugar

What are the four DNA bases?

A, T, G, C.

How do DNA bases pair?

A-T, G-C.

How many hydrogen bonds hold DNA base pairs together?

A-T = 2 bonds; G-C = 3 bonds

What is a codon?

3 nucleotides that code for one amino acid or a stop signal

What is a ribosome?

The organelle that assembles proteins from amino acids

What is a chromatid?

An identical copy of a chromosome made before cell division

What does it mean that DNA strands are antiparallel?

They run in opposite directions.

What is the sense strand? What does it carry?

strand that runs 5' to 3'; the coding sequence

What is the antisense strand? What is it used as?

The strand that runs 3' to 5' ; used as the template

What is a mutation? What are the 3 types?

A permanent change in DNA sequence; substitution, deletion, or insertion

What is RNA? (describe molecule, what does it do?)

A single-stranded molecule that carries DNA's instructions to make proteins

What does mRNA do? ^{m = messenger}

Carries the genetic code from DNA to the ribosome

What does tRNA do?

Transfers amino acids to the ribosome

What is rRNA? (2)

Makes up the ribosome and helps build the protein

What are the four RNA bases?

A, U, G, C (uracil replaces thymine).

How do RNA bases pair?

A-U, G-C.

What is transcription?

Copying DNA into mRNA.

What is translation?

Reading mRNA to build a protein at the ribosome.

What is a peptide bond?

The bond linking amino acids together.

What is keratin?

A tough protein made by skin cells.

What is deoxyribose sugar?

The sugar in DNA nucleotides.

What is a nucleotide?

The building block (monomer) of DNA/RNA.

What is a complementary strand?

A strand synthesized to match a template strand (will run in the antiparallel direction to the template strand)

What is a template strand?

The DNA strand used to build a matching mRNA strand.

What is a genome?

The full set of genetic material in a cell.