Cell And Molecular Biology Exam Ii

Front 1

RNA chain produced by transcription

Back 1

RNA transcript

Front 2

occurs with recognition of the promoter sequence

Back 2

Initiation

Front 3

initiation sequence indicating starting point

Back 3

promoter

Front 4

a subunit of polymerase responsible for recognizing the promoter sequence on DNA

Back 4

sigma factor

Front 5

the stage when the transcript is elongated

Back 5

Elongation

Front 6

occurs when transcript encounters the terminator sequence

Back 6

termination

Front 7

In what direction is mRNA transcribed?

Back 7

5' to 3'

Front 8

Order the following events:
-RNA splicing
-polyadenylation
-5' cap (RNA capping)

Back 8

1. 5' Cap
2. RNA splicing
3. Polyadenylation

Front 9

Where is the TATA box located?

Back 9

upstream of the gene, as part of the promoter sequence (-10)

Front 10

Which bases are purines?

Back 10

adenine, guanine

Front 11

Which bases are pyrimidines?

Back 11

cytosine, thymine

Front 12

A base pairs with what?

Back 12

Thymine (DNA), Uracil (RNA)

Front 13

C base pairs with what?

Back 13

Guanine (in both)

Front 14

Give the complementary sequence.
5'-GCATTCGTGGGGTAG-3'

Back 14

5'-GTACCCACGAATGC-3'

Front 15

In eukaryotic _______, DNA is complexed with proteins to form _______.

Back 15

chromosomes; chromatin

Front 16

The paternal and maternal copies of human chromosome 1 are ________.

Back 16

homologous

Front 17

The paternal copy of chromosome 1 and the maternal copy of chromosome would be an example of __________ pairs.

Back 17

nonhomologous

Front 18

Cytogeneticists can determine large-scale chromosomal abnormalities by looking at a patient's ___________.

Back 18

karyotype

Front 19

Fluorescent molecules can be used to paint a chromosome by virtue of DNA _______________, and thereby identifiy each chromosome using microscopy.

Back 19

hybridization

Front 20

the enzyme that unwinds DNA

Back 20

helicase

Front 21

prevents the re-annealing of unwound DNA strands

Back 21

single-stranded binding proteins

Front 22

this enzyme lays down the RNA primer required to start DNA replication

Back 22

Primase

Front 23

T/F. RNA polymerase can only extend an existing strand; therefore, it requires a primer.

Back 23

False; DNA polymerase requires a primer, but RNA polymerase does not.

Front 24

this enzyme removes RNA primer by hydrolyzing it

Back 24

RNase H

Front 25

This enzyme links short strands of DNA together.

Back 25

Ligase

Front 26

long, non-coding intervening sequences

Back 26

Introns

Front 27

Which sequence is typically longer introns or exons?

Back 27

Introns

Front 28

scattered pieces of coding; expressed sequences

Back 28

exons

Front 29

Explain the process of splicing.

Back 29

-each intron contains sequence that cues its removal
-snRNPs cleave the RBA at the intron-exon borders
-they covalently link exons together
-intron is cut out in the form of a lariat structure
-exons are stitched together
-each transcript receives poly-A-tail

Front 30

What are three benefits to RNA splicing?

Back 30

1. Different proteins produced from same gene.
2. Recombination between exons of different genes
3. Evolutionary history of genes

Front 31

nucleotides made of two-ring bases

Back 31

purines (Adenine and Guanine)

Front 32

nucleotides made of one-ring bases

Back 32

pyrimidines (Cytoseine and Thymine)

Front 33

base pair with two hydrogen bonds

Back 33

A=T

Front 34

base-pair with three hydrogen bonds

Back 34

C and G

Front 35

Chromosomes contain what two components?

Back 35

DNA and protein

Front 36

What is DNA made of?

Back 36

Two long polynucleotide chains held together by hydrogen bonding, known as DNA strands; nucleotides are covalently linked forming sugar-phosphate backbone

Front 37

When do chromosomes become visible?

Back 37

When they start to divide

Front 38

What is the 5' end of a DNA chain marked by?

Back 38

a phosphate group of one sugar

Front 39

What marks the 3' end of the DNA chain?

Back 39

a hydroxyl group of one sugar

Front 40

If a nucleotide were a knob and a hole, identify what the knob would be and what the hole would be.

Back 40

Knob-phosphate (5' phosphate)
hole (block)-sugar (3' hydroxyl group)

Front 41

What gives DNA get its chemical polarity?

Back 41

the way in which nucleotide subunits are linked

Front 42

In DNA, the polarity of one strand is oriented opposite to that of the other strand, what is this called?

Back 42

antiparallel

Front 43

The nucleotide sequences between the two strands can best be described as what?

Back 43

complimentary

Front 44

20-letter amino acid alphabet of protein

Back 44

the genetic code

Front 45

the complete set of information in an organism's DNA

Back 45

genome

Front 46

A human cell contains about ___ of DNA.

Back 46

2m

Front 47

A cell's nucleus is only about ___ in diameter.

Back 47

5-8um

Front 48

How can DNA fit into a nucleus?

Back 48

DNA molecules are packaged into chromosomes.

Front 49

How does DNA packaging occur?

Back 49

It is accomplished through specialized proteins that binds to the DNA and fold it.

Front 50

How do bacteria carry their genes?

Back 50

single, circular DNA molecule called a plasmid

Front 51

The specific classification of DNA complex and protein.

Back 51

chromatin

Front 52

What is the only pair of nonhomologous chromosomes in the human genome?

Back 52

The sex chromosomes because an X is inherited from the mother and a Y is inherited from the father; all other chromosome pairs are homologous.

Front 53

What is the main difference between euchromatin and heterochromatin?

Back 53

-Heterochromatin:the most highly condensed form of interphase chromatin
-euchromatin: the rest of the more extended states of interphase chromatin

Front 54

T/F. Chromatin in an interphase chromatin is the same throughout.

Back 54

False. It is not in the same packing state throughout; highly condensed and less condensed.

Front 55

Most of the DNA permanently folded into heterochromatin in the cell DOES/DOES NOT contain genes.

Back 55

DOES NOT

Front 56

Why is most of the DNA folded into heterochromatin not expressed into genes?

Back 56

The unusual packing in heterochromatin makes the genes resistant

Front 57

Inappropriate packaging of genes in heterochromatin can cause what?

Back 57

disease

Front 58

What happens in DNA hybridization?

Back 58

A set of chromosome-specific DNA molecules coupled to fluorescent molecules are used to "paint" chromosome a different color

Front 59

a display of the full set of 46 human chromosomes

Back 59

karotype

Front 60

What is used to detect chromosomal abnormalities associated with inherited defects and with cancer?

Back 60

Alternations in banding patterns; if chromosomes are lost of missing, changes can be detected by banding patterns

Front 61

What is it called when labeled DNA forms base pairs?

Back 61

Hybridizing

Front 62

What does unique banding patterns enable?

Back 62

It allows identification of each human chromosome

Front 63

What is the function of chromosomes?

Back 63

to carry genes

Front 64

A segment of DNA that contains instructions for making a particular protein

Back 64

gene

Front 65

There is a correlation between the ________ of an organism and the ____________ in its genome.

Back 65

complexity; number of genes

Front 66

T/F. In eukaryotes,most of the DNA carries critical information.

Back 66

False; in many eukaryotes, there a large excess of interspersed "JUNK" DNA that does not carry criticial information

Front 67

___ are arranged along chromosomes.

Back 67

Genes

Front 68

How many chromosomes do humans have?

Back 68

46 chromosomes

Front 69

T/F. Closely related species can have very different chromosome numbers.

Back 69

True.

Front 70

The process by which a DNA molecule replicates and separates into daughter cells at each cell division

Back 70

cell cycle

Front 71

The stage in which the cell is actively expressing genes

Back 71

interphase

Front 72

The stage in which the nucleus divides, one complete set of chromosomes is pulled to each end of the cell, and the cell divides to form two daughter cells

Back 72

mitosis

Front 73

What happens to the DNA and chromosomes during interphase and before cell division?

Back 73

DNA is replicated and chromosomes are duplicated.

Front 74

RNA and functional protein synthesis (cell cycle)

Back 74

Growth 1

Front 75

Structural proteins synthesis (cell cycle)

Back 75

G2

Front 76

DNA replication (cell cycle)

Back 76

S

Front 77

What occurs during interphase?

Back 77

gene expression and chromosome replication

Front 78

Each mitotic chromosome contains what?

Back 78

two identical daughter DNA molecules (chromatids)

Front 79

What are the basic units of chromatin structure?

Back 79

nucleosomes

Front 80

What are the two types of protein that bind to DNA?

Back 80

Histones; nonhistone chromosomal proteins

Front 81

Which protein is responsible for the nucleosome?

Back 81

histones

Front 82

How many time more compact is DNA than in its extended form?

Back 82

10,000 times

Front 83

DNA in interphase chromosomes is packed tightly with a compaction ratio of about ____-fold.

Back 83

1,000

Front 84

An individual nucleosome core particle consists of what parts?

Back 84

eight histone proteins (H2A, H2B, H3, H4) and linker-DNA (winds around histone octamer

Front 85

Levels of chromatin packing.

Back 85

DNA-->"beads on a string-->30-nm chromatin-->loops 300-nm (extended form)-->condensed form (700-nm)-->mitotic chromosome (1400nm)

Front 86

The structure of the 30-nm chromatin fiber may be a fluid mosaic of different ____ patterns.

Back 86

zigzag (variations)

Front 87

protein machines that use the energy of ATP hydrolysis to change the structure of nucleosomes

Back 87

chromatin remodeling complexes