Lecture 3

Question 1

how many base pairs are in a genome?

Answer 1

3 billion

Question 2

how does an offspring get its genome?

Answer 2

the offspring gets a set of genomes from each parent, one from the mother and the other from the father

Question 2

does the size of a genome relate to how complex an organism is?

Answer 2

no

Question 3

how many genes code for proteins?

Answer 3

20, 000

Question 4

how much of the genome is repetitive DNA?

Answer 4

about half of the genome

Question 5

how much of the genome codes for proteins?

Answer 5

about 1 percent

Question 6

what are lines?

Answer 6

long interspersed nuclear segments

Question 7

what are sines?

Answer 7

short interspersed nuclear segments

Question 8

what happens to Retrotransposons?

Answer 8

get made into RNA during transcription

Question 9

how do DNA-only transposons move through the genome?

Answer 9

through a DNA intermediate

Question 10

what are protein-coding exons?

Answer 10

segments of DNA that are translated into proteins

Question 10

what are simple repeats?

Answer 10

short segments of DNA that are repeated

Question 11

what are segment duplications?

Answer 11

large duplicated DNA segments within the genome

Question 12

what are unique sequences?

Answer 12

sequences within the genome that only occur once

Question 13

what are the regions that get spliced out of mRNA called?

Answer 13

introns

Question 14

how is DNA packaged in prokaryotes and why?

Answer 14

DNA is folded 1000 times to fit in the cell better

Question 15

is genome packaging easier in prokaryotes or eukaryotes and why?

Answer 15

prokaryotes because eukaryotes are more complex

Question 16

where is DNA held in the cell?

Answer 16

nucleus

Question 17

does the nucleus in eukaryotic cells have a membrane?

Answer 17

yes

Question 18

what is the job of Florence in Situ Hybridization?

Answer 18

technique to see certain DNA sequences within the cell

Question 18

what is the chromosome solution?

Answer 18

eukaryotic genome is packaged into chromosomes

Question 19

what do chromosomes consist of?

Answer 19

a long linear DNA molecule and chromatin

Question 19

what is the process of Florence in Siti Hybridization?

Answer 19

a probe binds to a DNA sequence of interest and the probe has to hybridize to bind to the DNA. The probe gives off a fluorescent signal which allows researchers to see the DNA segment of interest

Question 20

how many pairs of chromosomes are there?

Answer 20

23

Question 21

how many chromosomes are there in total?

Answer 21

46

Question 22

what is chromatin?

Answer 22

a complex of DNA and protein

Question 23

what does it mean that chromatin is dynamic?

Answer 23

chromatin can change to become more accessible for transcription

Question 23

what happens during the mitosis stage of cell division?

Answer 23

spindle fibres separate the chromosome pairs and put them at the edges of the cell. Then the cell divides

Question 24

what happens in the interphase stage of the cell cycle?

Answer 24

DNA duplicates

Question 25

what are the two main stages in the cell cycle?

Answer 25

interphase and mitosis

Question 26

what happens to chromatins during interphase?

Answer 26

they isolate from cells

Question 27

what is the fundamental unit of chromatins?

Answer 27

nucleosomes

Question 28

what is decondensation?

Answer 28

a process researchers do to loosen DNA structure

Question 29

what are histones?

Answer 29

small proteins rich in lysine and arginine

Question 30

what is the job of histones?

Answer 30

use their positive charge to balance the negative charge in DNA

Question 31

what are the four main proteins histones are main of?

Answer 31

H2A, H2B, H3 and H4

Question 32

what does an octamer core consist of?

Answer 32

H2A, H2B, H3 and H4 a pair of each protein

Question 32

what molecules form chromatin loops?

Answer 32

sequence-specific clamp proteins and cohesion

Question 33

what is H1?

Answer 33

a linker histone

Question 34

what replaces condensins when cells go through mitosis and why?

Answer 34

cohesins so the chromatin can loop and become more compact

Question 35

how much shorter does the DNA molecule become when packaged into a chromosome?

Answer 35

it becomes 10, 000 times shorter

Question 36

what molecules make changes in the chromatin structure?

Answer 36

Chromatin remodelling complexes and histone-modifying enzymes

Question 36

what is heterochromatin?

Answer 36

highly condensed regions of chromosomes

Question 37

what is the condensation like in chromatin?

Answer 37

constitutive always condensed or facultative condensed only in certain regions

Question 37

what type of chromosomes does heterochromatin have?

Answer 37

meiotic and mitotic chromosomes

Question 38

what region in the nucleus does heterochromatin lie?

Answer 38

in regions where gene expression is suppressed

Question 39

what is euchromatin?

Answer 39

non-highly condensed chromatin

Question 40

what is the degree of condensation like in euchromatin?

Answer 40

it varies

Question 41

what is the level of activity like in euchromatin?

Answer 41

it varies

Question 41

what region of the nucleus is euchromatin found in?

Answer 41

areas where genes can be expressed

Question 42

which molecules modulate the reversible switching from euchromatic to heterochromatic regions along chromosomes?

Answer 42

Localized covalent modification of histones, chromatin remodelling complexes, and RNA polymerase (transcription) complexes

Question 43

what is chromosome painting?

Answer 43

a technique that uses fluorescent or radioactive probes to label and visualize specific regions in the genome

Question 44

what chromosomes are found in the condensed chromosomal territory?

Answer 44

heterochromatin

Question 44

Is DNA replication conservative or semiconservative?

Answer 44

semiconservative

Question 45

What is the direction of DNA replication?

Answer 45

bidirectional growth starting from one point

Question 46

Where does DNA replication start?

Answer 46

replication origin at the same location

Question 47

which cells use bidirectional growth?

Answer 47

Eukaryotes and bacteria use this method

Question 48

What are some of the characteristics of the sequences at replication origins?

Answer 48

-Easy to open - A-T rich -Recognized by initiator proteins that bind to the DNA

Question 49

How many origins or replications do bacteria have?

Answer 49

one

Question 50

how many origins or replications do eukaryotes have?

Answer 50

multiple

Question 51

how does DNA replication proceed in bacteria?

Answer 51

circularly

Question 52

what is the symmetry of the replication fork like?

Answer 52

asymmetrical

Question 53

what are the ingredients for DNA synthesis? (6)

Answer 53

Origin of replication, primers, dNTPs, ATP (as an energy source), DNA polymerase, accessory proteins