Lesson 5

Question 1

What microscope is used to visualize detailed structure of a chromosome

Answer 1

Electron microscope

Question 2

When a cell is dividing, chromosomes get _____ and can be seen in what microscope?

Answer 2

shorter and fatter, light microscope

Question 3

packaged form of DNA

Answer 3

Chromosomes

Question 4

In the cell nucleus, DNA exists in what form

Answer 4

non-condensed

Question 5

When does DNA condense into chromosomes

Answer 5

During cell replication

Question 6

Carries a code that instructs the cell about which kind of proteins it should make

Answer 6

DNA molecule

Question 7

What do you call the end points of each chromosome?

Answer 7

Telomeres

Question 8

The upper arm of a chromosome

Answer 8

p arm

Question 9

The lower arm of a chromosome

Answer 9

q arm

Question 10

The region where two chromatids meets in a chromosome

Answer 10

Centromere

Question 11

Half a duplicated chromosome

Answer 11

Chromatid

Question 12

Responsible for a particular characteristic is always on the same relative position on the chromosome

Answer 12

Gene

Question 13

May be in different form of the gene on each chromosome when they are in pairs

Answer 13

Alleles

Question 14

In the 46 chromosomes, how many pairs are autosomal?

Answer 14

22 pairs

Question 15

In the 46 chromosomes, how many pairs are sex chromosomes?

Answer 15

1 (the 23rd)

Question 16

It is the pair that determines whether a fetus becomes male or female

Answer 16

Sex chromosomes

Question 17

Chromosomes where the genes on both pairs are capable of being fully expressed

Answer 17

Nonsex/ autosomal

Question 18

The absence of one X chromosome

Answer 18

Turner’s syndrome

Question 19

One of the two X chromosomes are turned off

Answer 19

X inactivation

Question 20

Abnormal or Normal: triple X syndrome

Answer 20

Often normal

Question 21

Abnormal or Normal: XYY syndrome

Answer 21

abnormal

Question 22

Tiny structures inside cell that synthesize molecules used for energy

Answer 22

Mitochondria

Question 23

Each mitochondrion contains its own ______

Answer 23

Circular chromosome

Question 24

Mitochondrial chromosomes also contain

Answer 24

DNA

Question 25

Mitochondrial DNA usually comes from

Answer 25

Mother

Question 26

The three minimal requirements for proper maintenance of chromosomes in cells

Answer 26

- centromere - telomere - origin of replication

Question 27

Basis for segregation and the region of the chromosome where kinetochore attaches

Answer 27

Centromere function

Question 28

Protein machine that mediates the alignment of duplicated chromosomes, then splitting into copies.

Answer 28

Kinetochore

Question 29

Cells with the wrong number of chromosomes are termed

Answer 29

Aneuploid

Question 30

Centromere position

Answer 30

center or towards the end

Question 31

Centromere structure

Answer 31

condensed heterochromatin structure

Question 32

Helps mediate attachment of the kinetochore to centromeres

Answer 32

histone H3 variant CENP-A

Question 33

Telomeres short repeated sequence

Answer 33

TTAGGG

Question 34

Adds new DNA to the 3' end of a DNA chain using an intrinsic RNA component of the enzyme to act as the template strand

Answer 34

Telomerase

Question 35

Discovered by Griffith and de Lange in 1999 that essentially hides the chromosome end, and means the ends of the chromosome is resistant to degradation or "repair

Answer 35

Tloop

Question 36

Cells that have limited proliferative capacity

Answer 36

Cells with short telomeres

Question 37

Cells that have much greater proliferative capacity

Answer 37

Long telomeres

Question 38

A significant component of aging

Answer 38

Cellular senescence

Question 39

The linear length of the human genome is about _____

Answer 39

two meters

Question 40

The basic unit of eukaryotic chromatin structure

Answer 40

Nucleosome

Question 41

A nucleosome consists of

Answer 41

Core octamer: (two copies each) - H2A - H2B - H3 - H4

Question 42

All histones are compact globular proteins with an extended tail rich in basic amino acids that are what charge?

Answer 42

positive charges

Question 43

The positive charge of the histone interacts with what?

Answer 43

The negative charge of the DNA phosphate backbone

Question 44

Each nucleosome consists how many histone proteins

Answer 44

8

Question 45

How many times does DNA wrap in each nucleosome

Answer 45

2 times

Question 46

Varies from gene to gene over the life of the cell

Answer 46

Higher order organization

Question 47

Mediates the packing of adjacent nucleosomes

Answer 47

histone H1 (linker histone)

Question 48

Popular model of DNA packaging

Answer 48

solenoid and zigzag

Question 49

Loosely packed and transcriptionally active, allowing genes to be expressed.

Answer 49

Euchromatin

Question 50

Highly condensed structure found in areas of the chromosome that aren't transcriptionally active

Answer 50

Heterochromatin (silent regions)

Question 51

The ability to adjust nucleosome positioning in chromatin is termed

Answer 51

Chromatin remodeling

Question 52

Important in assembly of nucleosomes de novo in recently replicated DNA

Answer 52

Remodeling complexes

Question 53

Remodeling complexes typically use energy from _____ to perform remodeling

Answer 53

ATP hydrolysis

Question 54

Modifications that alter, remodel, loosening association of DNA with nucleosomes in a chromatin state

Answer 54

Covalent modifications of histone

Question 55

What do covalent modifications do?

Answer 55

neutralize positive charges in histone tails so that the negatively charged DNA backbone no linger sticks to nucleosomes quite tightly

Question 56

Histone modifying enzymes

Answer 56

- histone acetylases and deacetylases - histone methylases - histone kinases

Question 57

The beads on a string; made up of DNA wrapped around histone proteins

Answer 57

Chromatin

Question 58

Critical events both for assembly of new nucleosomes after DNA replication

Answer 58

Acetylation and methylation

Question 59

Important for chromosome condensation prior to cell division

Answer 59

Phosphorylation

Question 60

Nucleosome regions where normal H2A is substituted with the H2A variant H2AZ

Answer 60

Stably heterochromatic

Question 61

What mediates the formation of the loop, and protection of the branch point?

Answer 61

TRF-2 protein (Telomere Repeat binding Factor -2)