Cell Cycle, DNA, and Gene Expression Flashcards

Fill-in-the-blank flashcards covering cell cycle, DNA structure and replication, transcription and translation, chromosome organization, meiosis, and polyploidy.

The process by which a cell nucleus divides to produce two genetically identical cells is __.

mitosis

The two processes in sexual reproduction that lead to new allele combinations are meiosis and __.

fertilization

DNA stores genetic __.

information

DNA is located in the in eukaryotes.

nucleus

RNA is mostly outside the .

nucleus

A nucleotide contains a sugar, a phosphate group, and a __.

nitrogenous base

Purines have rings.

two

Pyrimidines have rings.

one

In DNA, the total number of purines is approximately equal to the total number of .

pyrimidines

According to Chargaff's rules, the relative amounts of purines and pyrimidines can across species.

vary

DNA double-stranded helix is held together by bonds between base pairs.

hydrogen

In DNA base pairing, adenine pairs with .

thymine

During transcription, RNA polymerase binds to the on the template strand.

promoter

In RNA, thymine is replaced by .

uracil

DNA replication is semiconservative; the two strands are .

antiparallel

DNA replication usually proceeds from the replication fork (bidirectionally).

bidirectionally

Okazaki fragments are synthesized on the strand.

lagging

The enzyme that unwinds DNA is .

helicase

The enzyme that joins Okazaki fragments is .

ligase

Primase synthesizes a short RNA from the DNA template.

primer

The new strand is always synthesized in the direction.

5' to 3'

GC base pairs have hydrogen bonds.

three

DNA with a higher GC content has a melting temperature.

higher

During transcription, RNA synthesizes RNA using a DNA template.

polymerase

RNA polymerase binds the promoter on the strand (antisense/template).

antisense

The 5' cap added to pre-mRNA is called (7-methylguanylate).

7-methylguanylate

The Poly(A) tail is a stretch of at the 3' end.

adenines

During RNA processing, introns are removed and exons are .

ligated

The start codon in translation is , which codes for methionine.

AUG

Stop codons include UAA, UAG, and .

UGA

The ribosome has three sites: A, P, and .

E

The genetic code translates nucleotide triplets called into amino acids.

codons

The start codon AUG codes for the amino acid (Met).

methionine

The codon UUU codes for .

phenylalanine

Humans have autosomes numbered as pairs of chromosomes.

22

Humans have a diploid number of .

46

The region where sister chromatids are held together is the .

centromere

The core octamer around which DNA wraps to form a nucleosome consists of two of each of H2A, H2B, H3, and H4; H1 is the histone that helps stabilize higher-order structure.

linker

A nucleosome is formed when DNA wraps around an histone .

octamer

Meiosis comprises two divisions, I and II, without an intervening phase.

S phase

Crossing over occurs during I of meiosis, enabling reciprocal exchange of genetic material between non-sister chromatids.

prophase

Reductional segregation occurs when separate.

homologs

In spermatogenesis, one primary spermatocyte yields sperm.

four

In oogenesis, one primary oocyte yields one ovum and polar bodies.

three

Seedless watermelons are usually .

triploid

Banana is typically polyploid.

triploid

Sweet potato is polyploid.

hexaploid

Strawberry is typically polyploid.

octoploid