Biology 1610 Midterm 2 Exam

Gene

Sequence of nucleotides on DNA that determines the sequence of nucleotides on the RNA and thus the amino acids on the protein

Gene expression

the process by which DNA directs the synthesis of proteins

• All cells in a body have some genes and DNA but different cell types express different genes and make different proteins

mRNA

carries message in DNA to make protein

tRNA

helps read message in mRNA

rRNA

helps make protein from mRNA

chromosome

a long linear DNA double helix wrapped around proteins

ploidy

number of complete sets of chromosomes in a cell

• n= number of unique chromosomes

haploid

one set of unique chromosomes (1n)

diploid

two sets of unique chromosomes (2n)

• 2 of the same size same shape? yes→ 2n, no→1n (haploid)

genome

entire set of unique DNA instructions found in a cell

allele

an alternative version of a gene that may lead to different traits

sister chromatids

two identical copies of a single replicated chromosome that remain attached to each other

non-sister chromatids

one chromatid from each of the two homologous chromosomes

independent assortment

new, random possibilities of genes for the next generation

homologous assortment

pieces of DNA are broken and recombined to make new combinations of a gene

cross-over

the echange of genetic material between non-sister chromatids of paired homologous chromosomes during meiosis (occurs during prophase 1)

carrier

heterozygous

true-breeding

homozygous

at what point in meiosis does crossing over occur?

prophase 1

Purines

adenine and guanine

• Pure As Gold

Pyrimidines

thymine, cytosine, uracil

• CUT

DNA polymerase

synthesizes new DNA strands by reading original parent template strand

Helicase

separates DNA strands

primase

synthesizes RNA primer on seperated DNA strands

what direction does RNA polymerase read the template strand?

3’ to 5’ to make new DNA 5’-3’

what direction does the leading strand move?

5’ on the parent strand

where does transcription start and binds to it?

at the promoter, transcription factors.

What direction does RNA polymerase read the DNA template strand?

3’ to 5’ direction

what direction is the complementary single-stranded mRNA molecule built during transcription?

5’ to 3’

where does transcription end?

at the terminator sequence

How do you determine which DNA strand is the template strand during transcription?

1. Determine where the promoter is

2. new mRNA is made 5’ to 3’ in direction of promoter

3. template strand direction is 3’ to 5’

what enzyme catalyzes a peptide bond between the new amino acid in the A site and growing chain in the P site?

ribosome

what direction is mRNA read by the ribosome during translation?

5’ to 3’

G1 phase

• metabolism and growth

• prepare for DNA replication

S phase

DNA replication

G2 phase

• more growth

• prepare for mitosis

M (mitosis) phase

• cell division