Biochemical Basis of Heredity

Question 1

What are chromosomes made of?

Answer 1

DNA and protein

Question 2

DNA consists of a lot of _______________ but no _____________.

Answer 2

1. phosphorus
2. sulfur

Question 3

Proteins contain _____________ but very little _______________.

Answer 3

1. sulfur
2. phosphorus

Question 4

Rough strain Griffith experiment

Answer 4

the rough strain is nonvirulent so the mouse lives

Question 5

Heated killed smooth strain Griffith experiment

Answer 5

mouse lives

Question 6

smooth strain Griffith experiment

Answer 6

the smooth strain is virulent so the mouse dies

Question 7

rough strain and heated killed smooth strain Griffith experiment

Answer 7

all mice die

Question 8

What happened when the rough strain and heated killed smooth strain were injected into a mouse?

Answer 8

all mice died and the living bacteria was found of S type so this implies that R bacteria were transformed into S

Question 9

Transforming principle

Answer 9

carried genetic information, there is a chemical in one cell that is genetically changing the other

Question 10

What did Phoebus Levene do?

Answer 10

isolated nucleotide and figured out what they were made of

Question 11

What are nucleotides made of?

Answer 11

a sugar molecule, phosphate group, and a nitrogen-containing base

Question 12

Nitrogen containing bases

Answer 12

Adenine, guanine, cytosine, thymine

Question 13

What did Erwin Chargaff do?

Answer 13

found out how base pairs pair to each other

Question 14

What base pair corresponds to A?

Answer 14

T

Question 15

What base pair corresponds to G?

Answer 15

C

Question 16

What did Maurice Wilkins and Rosalind Franklin do?

Answer 16

took an X ray diffraction which showed that DNA was a helix

Question 17

Watson and Crick

Answer 17

created a DNA model showing how DNA is a double helix

Question 18

How is DNA orientated?

Answer 18

3’ – 5’ and 5’ – 3’

Question 19

What holds together base pairs?

Answer 19

hydrogen bonds

Question 20

Central Dogma

Answer 20

a theory stating that genetic information flows only in one direction from DNA to RNA to proteins or RNA directly to protein

Question 21

Three steps of the central dogma

Answer 21

1. replication
2. transcription
3. translation

Question 22

Replication occurs in the ….

Answer 22

DNA

Question 23

After DNA is replicated it resides in the __________.

Answer 23

nucleus

Question 24

Helicase

Answer 24

unwinds and holds apart DNA section to be replicated

Question 25

Primase

Answer 25

begins new DNA molecule with RNA primer

Question 26

DNA polymerase

Answer 26

brings in new DNA nucleotides to existing strand

Question 27

Exonuclease

Answer 27

removes RNA primer

Question 28

Ligase

Answer 28

seals sugar phosphate backbone

Question 29

What do binding proteins do?

Answer 29

stabilize separated strands of DNA

Question 30

Step one of DNA replication

Answer 30

helices binds to origin and separates strands

Question 31

Step two of DNA replication

Answer 31

binding proteins prevent single strands from rejoining

Question 32

Step three of DNA replication

Answer 32

primate makes a short stretch of RNA on the DNA template

Question 33

Step four of DNA replication

Answer 33

DNA polymerase adds DNA nucleotides to the RNA primer

Question 34

Step five of DNA replication

Answer 34

DNA polymerase proofreading activity checks and replaces incorrect bases just added

Question 35

Step six of DNA replicaiton

Answer 35

enzymes remove RNA primer and ligase seals sugar phosphate backbone

Question 36

What is the overall direction of DNA replication?

Answer 36

'5 to 3'

Question 37

What strand replicates smoothly?

Answer 37

the leading or continuous strand

Question 38

What does the discontinuous strand must do?

Answer 38

produces Okazaki fragments on the 5' to 3' template

Question 39

Where does transcription occur in?

Answer 39

the nucleus

Question 40

Where does translation occur?

Answer 40

the cytoplasm

Question 41

In transcription what serves as a template for RNA synthesis?

Answer 41

DNA

Question 42

What does RNA polymerase do in transcription?

Answer 42

begins at promoter region and adds nucleotides until a stop codon is reached

Question 43

What are the RNA nucleotides?

Answer 43

A, U, G, C

Question 44

rRNA

Answer 44

ribosomal RNA -forms the ribosomes with protein

Question 45

mRNA

Answer 45

messanger RNA -carries the code for protein synthesis (codons)

Question 46

tRNA

Answer 46

transfer RNA -picks up amino acid for the growing polypeptide chain (anticodons)

Question 47

What happens during transcription?

Answer 47

1. base sequence of new RNA strand is complementary to the template DNA strand which is the mRNA molecule 2. mRNA detaches

Question 48

How many nucleotide bases are on a codon?

Answer 48

3

Question 49

How many codons make up the genetic code?

Answer 49

64

Question 50

What does redundancy mean in the genetic code?

Answer 50

that more than one codon corresponds to one amino acid

Question 51

Start codon

Answer 51

AUG

Question 52

Stop codons

Answer 52

UAA, UAG, UGA

Question 53

What does tRNA do?

Answer 53

translates the genetic code anticodon base pairs with codon on mRNA and tRNA has a hook that allows the correct amino acids to pair

Question 54

How are genes expressed?

Answer 54

they are either on or off

Question 55

Name some ways genes are expressed:

Answer 55

1. some switched on/off throughout lifetime 2. some turned on only at certain times 3. some turned off permanently before birth

Question 56

Posttranscriptional modifications

Answer 56

1. introns are cut out 2. exons are joined together 3. the mRNA transcript is transported to cytoplasm for translation

Question 57

What do regulatory proteins do?

Answer 57

-speed up or halt transcription -may bind with noncoding DNA sequences and affect the transcription of a neighboring gene

Question 58

Positive regulation

Answer 58

if activator is on operator then transcription occurs

Question 59

Negative regulation

Answer 59

if a repressor is on an operator then no transcription occurs

Question 60

If no activator is present does transcription occur?

Answer 60

no

Question 61

If no repressor is present does transcription occur?

Answer 61

yes