9.6 DNA Replication and Chromosome Structure/DNA Structure ILM Flashcards Preview

Foundations Exam 3 > 9.6 DNA Replication and Chromosome Structure/DNA Structure ILM > Flashcards

Flashcards in 9.6 DNA Replication and Chromosome Structure/DNA Structure ILM Deck (30):
1

what are the two prymidines? is this one or two rings?

one ring, cytosine and thymine

2

how are nucleotides strung together? what kind of bond?

phosphodiester bond

3

what disease is characterized by abnormally short telomere sequences? affects skin, nails, bone marrow cells. gives effect of premature aging

dyskeratosis congenita

4

what happens when telomeres become too short?

cells become senescent and stop dividing

5

telomerase is re-activated in what types of cells?

cancer cells

6

special repeating segments at the end of DNA

telomeres

7

What enzyme gets rid of the RNA priming fragments on the lagging strand?

ribonuclease H

8

what are the two purines? is this one or two rings?

two rings, adenine and guanine

9

What enzyme combines fragments with the growing strand by joining OH on a 3' end with a triphosphate on a 5' end?

DNA ligase

10

the nucleotides in DNA and RNA are based off a ___ carbon sugar (number)

5

11

what direction can DNA synthesis occur in?

5' to 3' direction

12

the leading strand in DNA synthesis is replicated __________, while the lagging strand is replicated _____________.

continuously, discontinuous

13

What enzyme synthesizes telomeres?

telomerase

14

a nucleotide consists of 3 things. What are they?

a simple sugar, a phosphate group, and a base

15

in double helix structure, how are the two strands of DNA held together? what force?

hydrogen bonding

16

What enzyme sits on DNA above the replication fork and ensures correct unwinding of the strand? Making sure there are no knots or anything.

topoisomerase

17

DNA polymerase does not have inherent affinity for DNA. What complex keeps DNA polymerase attached to DNA?

sliding clamp complex

18

what are the pairs of nucleotides? (purine and prymidine pairing)

A-T, C-G

19

there are 4 bases in DNA nucleotides. What are they?

thymine, adenine, cytosine, guanine

20

what enzyme does most of the DNA synthesis?

DNA polymerase

21

if RNA, then _____ is replaced by a ______ (nucleotide names)

thymine, uracil

22

are DNA residues positive or negative?

negative

23

which is more stable, A-T rich DNA or C-G rich DNA? Why?

C-G rich DNA, they make 3 H bonds between nucleotides (instead of the 2 by A-T)

24

what site allows duplicated DNA molecules to be pulled apart into daughter cells during cell division?

centromeres

25

are histone proteins positive or negative?

incredibly positive

26

DNA polymerase can't begin synthesis without a primer. There needs to be either a DNA or RNA primer for it to extend synthesis. What enzyme makes the RNA primers for the lagging strand?

DNA primase

27

when is telomerase enzyme active? (normal, 3 places)

gamete formation, adult stem cells, embryonic stem cells

28

in DNA, the sugar of the nucleotide is called _____________

deoxyribose

29

in RNA, the sugar of the nucleotide is called ______

ribose

30

what unwinds DNA?

DNA helicase