Chapter 18

Question 1

cells don’t replicate themselves, ____ replicates itself

Answer 1

DNA

Question 2

Transforming principle: (by _____ and ___) rough and smooth strains in mice

Answer 2

Oswald Avery and Fredrick Griffith

Question 3

chemists to solve mouse case: _____ and ____

____enters cells, not protein, so proved that DNA codes for _____, not proteins

Answer 3

Hershey and Chase
DNA
genes

Question 4

what makes up a single nucleotide?

Answer 4

1 deoxyribose sugar, phosphate, base (ACTG)

Question 5

What are the 4 nitrogenous bases?

Answer 5

A-adenine
T- thymine
C- cytosine
G- guanine

Question 6

What is Chargaff’s rule of base pairing (example)

Answer 6

A=T and C=G

so if 17% T then also 17% A

Question 7

What did Rosalind Franklin do?

Answer 7

took pics of DNA with x-rays

figured out double helix shape, and that bases are on the inside with phosphate and sugar on the outside

Question 8

RNA is different from DNA in what ways?

Answer 8

• leaves the nucleus
• sugar backbone is ribose (not deoxyribose so it has all its O2)
• single stranded, not double helix
• can be tRNA, mRNA, or rRNA
• 3 bases code for an amino acid (codon- triplet coding)

Question 9

If you have 2 codons, how many amino acids do you have? How many bases?

Answer 9

2 codons = 2 amino acids = 6 nitrogenous bases

Question 10

What did Watson and Crick do?

Answer 10

produced a structural model of DNA with double helix and complimentary base pairs (took everyone else’s ideas)

Question 11

____ makes up all of the DNA in the cell (all genes in body)

Answer 11

genome

Question 12

Steps of DNA replication

Answer 12

1. Initiation
2. elongation
3. termination

Question 13

What are helicases and what do they do?

Answer 13

enzymes that cut/ unwind the DNA (in the first step of DNA replication- initiation), forming a replication bubble… if bubble keeps expanding = replication fork

Question 14

What holds the unzipped DNA apart and serves as a template for new bases? (in initiation)

Answer 14

SSB- single strand binding proteins

Question 15

____ makes up primer, which serves as a starting point, constructed by ____ _______

Answer 15

RNA, primase enzyme

Question 16

what splices the okazaki fragments ?

Answer 16

DNA ligase

Question 17

Transcription

Answer 17

splitting DNA and making a copy of RNA

Question 18

Translation

Answer 18

proteins are made by bringing amino acids as described by the mRNA

Question 19

in which of the 2 major steps in making proteins does the RNA messenger leave the nucleus?

Answer 19

translation

Question 20

cancer causing gene

Answer 20

oncogenes

Question 21

What is a teratogen + example

Answer 21

something that causes a mutation (changes dna)

ex. x-rays, smoking, etc

Question 22

2 types of mutagens (causes of mutations) with examples

Answer 22

1. physical (x-rays, gamma rays, UV radiation, etc)

2. chemical or carcinogens ( smoke, gas fumes, nitrites)

Question 23

2 types of mutations with definitions

Answer 23

1. point mutation: substitution of one nucleotide for another
2. frameshift mutation: nucelotide insertions or deletions (sliding)

Question 24

silent mutation

Answer 24

no apparent affect on polypeptide produced

Question 25

mis-sense mutation

Answer 25

produces an altered or different protein (eg sickle cell)

Question 26

non-sense mutation

Answer 26

does not produce a functional polypeptide (always make a stop- incomplete protein)

Question 27

somatic mutations are in ____ cells, and germ-line mutations are in ____ cells

Answer 27

body cells | sex cells

Question 28

recombinant DNA

Answer 28

DNA molecules formed by laboratory methods of genetic recombination (such as molecular cloning) to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in the genome.

Question 29

gene splicing/ engineering

Answer 29

genetic info from 1 organism is spliced into the chromosome of the other - 2 organisms that would never exchange genetic info are joined

Question 30

eg of recombinant DNA: insulin production. explain the 4 steps

Answer 30

1. cut out donor gene for insulin with restriction enzyme(specific cuts leaving sticky ends) 2. cut bacterial plasmid with same enzymes 3. use ligase enzyme to fuse donor gene into the plasmid (join sticky ends) 4. the transgenic bacteria produce insulin and we harvest it

Question 31

DNA is/ is not a protein

Answer 31

is not! it is a source for RNA production which then can produce protein

Question 32

what is the role of polymerase in DNA replication?

Answer 32

adds nucelotides to growing strands

Question 33

nucelic acids are/ are not a major grouping of proteins in cells

Answer 33

are not

Question 34

Purine bases are ____ (2ring/ 1 ring) and includes bases __ and ___

Answer 34

``` 2 ring (big) A and G ```

Question 35

pyrimidine bases are ___( 1 or 2 ring) and includes bases __, ___, and ___

Answer 35

``` 1 ring (small) C, T, and U ```

Question 36

C and G have how many H-bonds between them?

Answer 36

3 H bond

Question 37

A and T have how many H bonds between them?

Answer 37

2 h bond

Question 38

catabolic = cutting or adding?

Answer 38

cutting | anabolic= adding

Question 39

what is the last step in transcribing DNA to mRNA?

Answer 39

the mRNA carries the message to the ribosome

Question 40

mRNA has ____ and tRNA has ________ | codons/ anti-codons

Answer 40

codons, anti-codons

Question 41

mRNA is synthesized in ___

Answer 41

transcription

Question 42

tRNA brings amino acids to the ___

Answer 42

ribosome

Question 43

a polypeptide is a sequence of _____

Answer 43

amino acids

Question 44

tRNA transfers amino acids in _____

Answer 44

translation

Question 45

ribsomes are the site where ___ takes place

Answer 45

translation

Question 46

explain the steps of genetic engineering (restriction and ligase enzymes)

Answer 46

restriction enzymes are added to a gene of intrest to cut them, exposing sticky ends. Different DNA is introduced, and cut with the same restriction enzymes (same stick ends). DNA ligase attaches them (with the corresponding sticky ends) and then you have recombinant DNA!

Question 47

DNA has a slightly ___ charge

Answer 47

negative