Bio 101 Final Hap

Front 1

Who demonstrated that DNA, not protein, is the genetic material of bacteriophages?

Back 1

Alfred Hershey and Martha Chase

Front 2

Who showed that the DNA composition varies b/w species; the number of A & T bases are equal, whereas the number of G & C bases are equal?

Back 2

Erwin Chargaff

Front 3

Who used X-ray crystallography to produce an X-ray diffraction image of DNA which served as the most critical piece of data in the elucidation of this molecule's structure?

Back 3

Roslyn Franklin

Front 4

Who proposed the correct structure of DNA: a double helix with external sugar-phosphate backbones and internal nitrogenous bases that hydrogen bond to each other via specific base pairings?

Back 4

Watson and Crick

Front 5

What are the 3 parts of a DNA nucleotide?

Back 5

Sugar

Phosphate

Nitrogenous base

Front 6

Name the 4 nitrogenous bases of DNA & identify each as either a purine (2 ring base) or a pyrimidine (1 ring base)

Back 6

Adenine (A)-Purine

Guanine (G)-Purine

Thymine (T)-Pyrimidine

Cytosine (C)-pyrimidine

Front 7

Name the DNA base pairings that occur in the DNA molecule.

Back 7

A & T

G & C

Front 8

What kind of bonds hold the base pairs together in DNA?

Back 8

Hydrogen bonds

Front 9

What kind of bond links the sugars of 2 adjacent nucleotides together via a phosphate group?

Back 9

Phosphodiester

Front 10

How is DNA's sugar phosphate backbone oriented in its 3-D structure?

Back 10

Anti-parallel. 3'-5' the other side is 5'-3'

Front 11

Does DNA have a charge? If yes, what is causing this charge?

Back 11

Yes. Negative b/c of the phosphates

Front 12

Who performed experiments which supported the semi-conservative model for DNA replication?

Back 12

Matthew Meselson & Franklin Stahl

Front 13

Where does DNA replication begin?

Back 13

Origins of replication

Front 14

Which enzyme unwinds the DNA double helix at the replication fork?

Back 14

Helicase

Front 15

Which enzyme synthesizes RNA primers using potential DNA as the template?

Back 15

Primase

Front 16

When referring to the DNA strand as either running in the 5'-3' direction or 3'-5' direction, what do the 5' & 3' refer to?

Back 16

The carbons of the 5 carbon sugar

Front 17

In which direction is DNA synthesized?

Back 17

5'-3'

Front 18

The ______ strand of DNA is synthesized continuously, growing in the direction of the replication fork.

Back 18

Leading

Front 19

The ______ strand of DNA is synthesized in fragments, and grows away from the replication fork.

Back 19

Lagging

Front 20

The fragments of the lagging strand are called________.

Back 20

Okazaki fragments

Front 21

Which enzyme catalyzes the elongation of the daughter DNA strands?

Back 21

Polymerase 3

Front 22

Which enzyme replaces RNA primers with DNA nucleotides?

Back 22

DNA polymerase 1

Front 23

Which enzyme joins fragments together in the lagging strand (3'-5')

Back 23

DNA ligase

Front 24

Which enzyme cuts out and replaces damaged stretches of DNA?

Back 24

nuclease

Front 25

A permanent change in the DNA sequence is called a ________.

Back 25

mutation

Front 26

Are mutations always bad? Why or why not?

Back 26

No, changes can help species adapt to different environments

Front 27

Chromatin consists of DNA associated with proteins called ________.

Back 27

Histones

Front 28

When chromatin is highly condensed, it is called _________.

Back 28

heterochromatin

Front 29

When chromatin is less compacted, its called_______.

Back 29

enchromatin

Front 30

Which form of chromatin is accessible for transcription?

Back 30

Euchromatin

Front 31

Circular pieces of DNA found in bacterial cells that are used as cloning vectors (vehicles) for carrying genes of interest to target cells are called _______.

Back 31

Plasmids

Front 32

What kind of enzymes cut DNA strands at specific DNA sequences?

Back 32

Restriction enzymes

Front 33

Which technique is used to separate DNA fragments based on size?

Back 33

Gel Electrophoresis

Front 34

Which technique is used to mass produce specific target sequences of DNA?

Back 34

(PCR) polymerase chain reaction

Front 35

How does RNA differ from DNA?

Back 35

Sugar consists of ribose instead of deoxyribose

The base Uracil (U), rather than thymine (T)

RNA is single stranded instead of double stranded

Front 36

Differentiate b/w the following terms replication, transcription, and translation.

Where in the cell do each of these events take place?

Replication

Back 36

DNA is being replicated into another strand of DNA (nucleus)

Front 37

Differentiate b/w the following terms replication, transcription, and translation.Where in the cell do each of these events take place?

Transcription

Back 37

Conversion of DNA to RNA (nucleus)

Front 38

Differentiate b/w the following terms replication, transcription, and translation.Where in the cell do each of these events take place?

Translation

Back 38

Going from RNA to protein. (Ribosomes in cytoplasm)

Front 39

Why does transcription and translation occur almost simultaneously in prokaryotes, but not in eukaryotes?

Back 39

In eukaryotes transcription occurs in the nucleus while translation occurs in the cytoplasm. Since prokaryotes lack nuclei, both events occur in the cytoplasm and can thus occur simultaneously.

Front 40

How many consecutive nucleotides on the mRNA transcript code for a specific amino acid?

Back 40

3

Front 41

What is the set of nucleotides on a RNA called?

Back 41

A codon

Front 42

In which direction are codons read on the mRNA transcript?

Back 42

5'-3'

Front 43

Why is the genetic code considered redundant, but not ambiguous?

Back 43

Several codons can code for the same amino acid, but each codon only codes for one amino acid.

Front 44

How many different amino acids are used to build proteins?

Back 44

20

Front 45

How many different codons exist in the genetic code?

Back 45

64

Front 46

How many RNA triplets (codons) code for amino acids?

Back 46

61

Front 47

How many are "start" codons?

Back 47

1

Front 48

How many are stop codons?

Back 48

3

Front 49

What is the first amino acid added to any new polypeptide chain?

Back 49

Methionine

Front 50

How does the genetic code provide for the unity and the diversity of life?

Back 50

Unity: genetic code is universal in all living things

Diversity: different sequences code for different proteins which promote different developments/traits and in turn different organisms.

Front 51

Which enzyme catalyzes RNA synthesis?

Back 51

RNA polymerase

Front 52

Does RNA polymerase need another enzyme to unwind the DNA?

Back 52

No the enzyme can untwist the DNA strndds w/o the assistance of another enzyme

Front 53

In which direction does the RNA polymerase assemble the polynucleotide?

Back 53

5'-3'

Front 54

Does RNA Polymerase require a primer to elongate the chain?

Back 54

No

Front 55

The region of DNA which signals where RNA polymerase binds and transcription starts is called the ________.

Back 55

Promoter

Front 56

List the sequential stages of transcription

Back 56

Initiation

Elongation

Termination

Front 57

The non-coding regions of the mRNA are called ______, while the coding regions are called ______.

Back 57

Introns

Exons

Front 58

How is the pre-mRNA modified before exiting the nucleus?

Back 58

Modified guanine nucleotide cap is added to the 5' end of transcript

A poly-A tail is added to the 3' end of the transcript

Introns are spliced out and exons joined

Front 59

What are the functions of these modification?

Back 59

Faciliatates export out of nucleus

Protects mRNA from degradation by hydrolytic enzymes

Helps ribosome attach to 5' end of transcript

mRNA contains continuous coding sequence.

Front 60

The ______ is the complex involved in cutting out introns and "splicing" together the exons of the pre-mRNA.

Back 60

spliceosome

Front 61

How do some genes give rise to more than one polypeptide?

Back 61

Alternative RNA splicing

Front 62

Describe the structure of the RNA molecules

Back 62

RNA molecules consist of a single RNA strand that is only about 80 nucleotides long

RNA molecules can base pair with themselves. Looks like a clover leaf

It carries a specific amino acid on one end that corresponds to a specific nucleotide triplet located on the other end of the molecule

Flattened info one plane a RNA molecule

Front 63

What does RNA do?

Back 63

Each RNA can translate a particular mRNA codon into a given amino acid

Front 64

Distinguish b/w the anticodon and the codon

Back 64

The anti-codon is the region in the RNA which is complementary to a specific codon in the mRNA

Front 65

Where does translation occur?

Back 65

Ribosomes in cytoplasm

Front 66

Where are the ribosomal subunits synthesized?

Back 66

Nucleolus

Front 67

What kind of RNA makes up the bulk of these structures and catalyzes protein synthesis?

Back 67

rRNA

Front 68

What occurs during the initiation stage of translation?

Back 68

Assembly

Front 69

What occurs during the elongation stage of translation?

Back 69

Codon recognition

Peptide bond formation

Translocation

Front 70

What occurs during the termination stage of translation?

Back 70

Termination occurs when the stop codon in the mRNA reaches the end

The s site accepts a protein called a release factor

the release factor causes the addition of a water molecule instead of an amino acid

The reaction releases the polypeptide and the translator assembly then comes apart.

Front 71

Where does all protein synthesis begin?

Back 71

Cytosol

Front 72

Differentiate b/w free and bound ribosomes.

Back 72

Free: free floating in cytoplasm that makes proteins that end up in cytoplasm

Bound: create proteins that are secreted or membrane proteins. (on ER)

Front 73

Are mRNA transcripts translated by more than one ribosome before degradation?

Back 73

Yes

Front 74

Mutations represent changes in the ________.

Back 74

DNA

Front 75

Distinguish b/w silent mutations, missense mutations and nonsense mutations.

Silent

Back 75

have no effect on the amino acid produced by a codon b/c of redundancy in the genetic code

Front 76

Distinguish b/w silent mutations, missense mutations and nonsense mutations.

Missense

Back 76

Still code for an amino acid, but not the correct amino acid (ex. substitution mutations)

Front 77

Distinguish b/w silent mutations, missense mutations and nonsense mutations.

Nonsense

Back 77

Change in amino acid codon into a stop codon, nearly always leading to a nonfunctional protein.

Front 78

What is a frame shift mutation?

Back 78

When the insertion or deletion of nucleotides alters the reading frame of genetic message.

Front 79

Given the following template strand of DNA what would be the corresponding mRNA sequence?

TACATGTCA

Back 79

AUGUACAGU

Front 80

What amino acid sequence would be coded by a DNA template strand that reads:

TACGGCAGT

Back 80

AUGCCGUCA

MetProSer

Front 81

How does the addition of acetyl groups (acetylation) to histones affect chormatin structure and function?

Back 81

Loosens chromatin structure, promoting the initiation of transcription.

Front 82

How does the addition of methyl groups (methylation) to histones affect chromatin structure and function?

Back 82

Condenses chromatin and leads to reduced transcription

Front 83

What is epigenetic inheritance?

Back 83

Inheritance of traits transmitted by mechanisms not directly involving the nucleotide sequence

Front 84

Why is DNA methylation an example of epigenetic inheritance?

Back 84

Methylation pattern (not part of nucleotide sequence) is inherited in daughter DNA strand

Front 85

How does DNA methylation affect gene transcription?

Back 85

Makes gene inaccessible for transcription (gene is not expressed)

Front 86

Control elements are segments of noncoding DNA that serve as a binding site for __________.

Back 86

Transcription factors

Front 87

Distal control elements are also called

Back 87

enhancers

Front 88

_______ bind to enhancers.

Back 88

Activators

Front 89

What are repressors?

Back 89

Transcription factors that inhibit expression of a particular gene

Front 90

The presence of available _______ in different cell types specific for certain enhancer, regulate cell type specific transcription in eukayotic cells

Back 90

Activators

Front 91

How are all the genes that produce products for a given metaboilc pathway coordinately regulated?

Back 91

All co-expressed genes possess the same combination of control elements that are recognized by specific activators: transcription of those genes is simultaneously promoted.

Front 92

Discuss alternative RNA splicing as a post-transcriptional mechanism for gene expression

Back 92

Differnet mRNA molecules are produced from the same primary transcript, depending on which segments of the pre-mRNA are treated as introns or exons.

Front 93

Which part of the mRNA transcript influences its life span?

Back 93

Untranslated region (UTR) at the 3' end

Front 94

The addition of ______ to a protein tags it for destruction.

Back 94

Ubiquitin

Front 95

What does a significant amount of the genome code for?

Back 95

Noncoding RNAs (ncRNAs)

Front 96

What are examples of Noncoding RNAs

Back 96

MicroRNAS(mRNAs), small interfering RNAs (siRNAs)

Front 97

What do these noncoding RNAs do?

Back 97

Interfere with translation, degrade mRNA, or block translation. Or may prevent transcription by modifying chromatin to heterochromatin

Front 98

What needs to be isolated from cells to determine which genes are being expressed?

Back 98

mRNA

Front 99

Which technique is used to make complementary DNA from mRNA?

Back 99

RT-PCR

Front 100

Which technique uses genome-wide expression studies to nalyze differential gene expression b/w two samples (e.g. tumor vs normal tissue)?

Back 100

DNA microarray assays

Front 101

What is genomics?

Back 101

The study of whole sets of genes and their interactions

Front 102

What was the Human Genome Project?

Back 102

Sequencing of all of the DNA in the human genome

Front 103

How long did it take to complete the Human Genome Project?

Back 103

13 years

Front 104

Which techniques greatly accelerated the sequencing of the human genome?

Back 104

Automated DNA sequences

Whole-genome shotgun approach

Front 105

What is GenBank?

Back 105

a U.S. government regulated database of sequenced genes, predicted protein sequences, etc. that is available to the public on the internet

Front 106

What are the units used to measure the size of the genome?

Back 106

Million base pairs (Mb)

Front 107

Approx. how many genes are in the human genome?

Back 107

21,000

Front 108

How does the gene density in the human genome compare to the gene density in prokaryotic genomes?

Back 108

Lower gene density in human genome

Front 109

What is missing from the genome of bacterial cells?

Back 109

Introns (e.g. 7 gnes per Mb in human genome as 950 genes per Mb in e. coli

Front 110

What percentage of human genome code consists of exons that code for proteins, tRNA or rRNA?

Back 110

1.5%

Front 111

_____________ represent regions of DNA that move from one site to another in a cell's DNA.

Back 111

Transposable elements

Front 112

Evaluation of repetitive DNA such as short tandem repeats (STRs) is used for _________.

Back 112

genetic profiling

Front 113

What underlies the evolution of the genome?

Back 113

Mutation, incorporated during meiosis

Front 114

What can we learn with comparative genome studies?

Back 114

The evolutionary histroy of life

Front 115

Which species shares the highest homology with the human genome?

Back 115

Chiimpanzees

Front 116

Genes that are evolving the fastest code for __________.

Back 116

Transcription factors