Bio 12 Exam Review - Dna Structure

Front 1

Phosphate end sugar held together by ______________ ________?

Back 1

phosphodiester bonds

Front 2

Sugar & nitrogenous bases held together by _____________ __________?

Back 2

glycosyl bonds

Front 3

DNA strands run __________?

Back 3

anti parallel (5' to 3' and 3' to 5')

Front 4

Genome

Back 4

total DNA in a cell

Front 5

Gene

Back 5

functional units of DNA

Front 6

structure of prokaryotic cells?

Back 6

circuler, double-stranded DNA

Front 7

what are histones?

Back 7

special proteins that FNA wraps around to form nucleosomes

Front 8

DNA is a ____________ charged molecule

Back 8

negatively

Front 9

what are plasmids?

Back 9

small circular DNA that are in prokaryotic cells, carry non-essential genes

Front 10

DNA replication is _____ - _______________

Back 10

semi-conservative

Front 11

what does 'semi-conservative' mean?

Back 11

one original parent strange and one newly synthesized strand

Front 12

DNA must "unzip" using the enzyme:

Back 12

DNA helicase

Front 13

what does DNA helicase do?

Back 13

breaks the H-bonds between base pairs, forms replication fork

Front 14

What are single-stranded binding proteins (SSB's) ?

Back 14

keeps the 2 strands apart

Front 15

DNA gyrase

Back 15

relieves tension in the unwinding strand

Front 16

what direction must strands always synthesize in?

Back 16

5' to 3'

Front 17

what does the leading strand do?

Back 17

begins replication using an RNA primer

Front 18

what are 'Okazaki fragments'?

Back 18

short fragments in which the lagging strand is composed of

Front 19

Okazaki fragments are connected by _____ ________.

Back 19

DNA ligase

Front 20

repeating sequences of DNA at the end of chromosomes that protect coding regions from being lost during replication

Back 20

telomeres

Front 21

what is the 'Hayflick Limit'?

Back 21

when the number of times that a cell can be divided until all telomeres are lost

Front 22

the period in a cells lifespan when it loses the ability to divide and grow; cell again

Back 22

cell senescence

Front 23

when a cell reaches 'hayflick limit', _____ ___________ takes place

Back 23

cell senescence

Front 24

if someone has shortened telomeres, what can happen?

Back 24

age prematurely, short lifespan

Front 25

enzyme that adds new telomere sequences to ends of chromosomes

Back 25

telomerase

Front 26

The Central Dogma

Back 26

transcription & translation

Front 27

structure of RNA?

Back 27

- contains ribose sugar

- uracil instead of thymine

- single stranded

Front 28

what are the types of RNA?

Back 28

mRNA, tRNA, rRNA

Front 29

RNA polymerase bonds to promoter

Back 29

Initiation phase of transcription

Front 30

ribosomes bonds to mRNA

Back 30

initiation phase of translation

Front 31

mRNA transcript is released from DNA + exits nucleus

Back 31

termination phase of transcription

Front 32

elongation phase of translation

Back 32

amino acids are brought to ribosomes using tRNA

Front 33

termination phase of translation

Back 33

ribosome falls off mRNA & polypeptide is released

Front 34

copy of DNA segment is made into mRNA

Back 34

elongation phase of translation

Front 35

mRNA mods to transcription?

Back 35

capping, tailing, splicing

Front 36

introns vs. exons?

Back 36

introns are spliced out, exons are left alone (transcription)

Front 37

what are 'operons'?

Back 37

a cluster of genes under the control of one promoter & one operator in prokaryotic cells

Front 38

lac operon is known as an ________.

Back 38

inducer

Front 39

trp operon is known as a _________.

Back 39

repressor

Front 40

errors made in the DNA sequence

Back 40

mutations

Front 41

causes of mutations?

Back 41

- spontaneous, no known source

- exposure to mutagenic agents

Front 42

example of a mutagenic agent?

Back 42

UV rays, x-ray chemicals