Ch 7 Molecular Genetics

Question 1

Griffith (1927)

Answer 1

discovered bacterial transformation

Question 2

bacterial transformation

Answer 2

ability of bacteria to alter their genetic makeup by absorbing foreign DNA milecules from other bacterial cells and incorporating the foreign DNA in their own

Question 3

Avery Macleod and Mcarty

Answer 3

published that Griffith’s bacteria were transferring DNA

Question 4

Hershey and Chase

Answer 4

proved DNA not proteins is the molecule of inheritance.

Question 5

Rosalind franklin

Answer 5

critical to Watson and crick’s model of dna

Question 6

watson and crick

Answer 6

won nobel prize for correctly describing structure of DNA as double helix

Question 7

Hershey and chase experiment

Answer 7

tagged bacteriophages with radioactive isotopes 32P and 35S. FOund stuff

Question 8

Role of hydrogen bonds in DNA

Answer 8

pair together nucleotides of opposite chains. also site of unzipping during replication

Question 9

semiconservative replication

Answer 9

proved by meselson and stahl. where DNA replication makes two new molecules from one old strand and one new.

Question 10

when does dna replication occur during cell cycle

Answer 10

interphase

Question 11

what catalyzes new DNA replication

Answer 11

DNA polymerase. it also proofreads each DNA strand

Question 12

how do eaukaryotic cells cope with possible loss of genes at end of chromosomes>?

Answer 12

have special repeating nonsense nucleotide sequences at ends of each chromosome, called telomeres

Question 13

Messenger RNA

Answer 13

carries messages directly from DNA in the nucleus to the cytoplasm during the making of a protein. carries triplet nucleotides called codons

Question 14

transfer rna

Answer 14

cloverleaf shape. carries amino acids to mRNA at ribosome to form polypeptide. triplet nucleotides are anticodons.

Question 15

ribosomal rna

Answer 15

structural makes up the ribosome

Question 16

transcription

Answer 16

DNA makes RNA. Facilitated by RNA polymerase, occurs in nucleus. Triplet code of DNA transcribed to codon sequence in mRNA

Question 17

RNA polymerase

Answer 17

facilitates transcription

Question 18

introns

Answer 18

RNA regions that dont code for proteins and are removed by enzymes. (intervening sequences)

Question 19

exons

Answer 19

coding regions, non-introns. after RNA is cut and leaves the nucleus, it is much shorter becuase exons are left

Question 20

Translation; what? where? how?

Answer 20

mRNA is converted into amino acid. Occurs in the ribosome. Amino acids (in cytoplasm) are carried by tRNA to the codons of mRNA at ribosome, use base pair rules.

Question 21

can tRNA bind to two different codons?

Answer 21

yes

Question 22

do cells make every protein all the time?

Answer 22

no, pancreas cells dont always need to make insulin. sometimes they are turned off.

Question 23

operons

Answer 23

cluster of functional genes and the switches that turn them on/off

Question 24

Lac operon

Answer 24

inducible operon, turned off usually unless actively triggered to turn on (by enviro)

Question 25

represible operon

Answer 25

always turned on unless actively turned off because its not needed

Question 26

two parts to an operon

Answer 26

promoter and operator

Question 27

promoter (operon)

Answer 27

the on switch. binding site of RNA polymerase, which must always bind to DNA before transcription.

Question 28

Operator (operon)

Answer 28

binding site for the repressor that turns of the lac operon.

Question 29

TATA box

Answer 29

part of operon with sequences of alternating thymine and adenine, helps RNA polymerase bind to promoter.

Question 30

point mutation

Answer 30

simplest mutation; base pair substitution where one nucleotide converts to another.

Question 31

insertion and deletion

Answer 31

gene mutations that aer caused by one nucleotide. insertion is addition of letter, deletion is removal of letter. both cause frameshifts!

Question 32

aneuploidy

Answer 32

chromosome mutation where there is any abnormality in the number of chromosomes

Question 33

polyploidy

Answer 33

chromosome mutation, having extra ets.

Question 34

nondisjunction

Answer 34

causes aneuploidy and polyploidy, failure of homologous pairs to separate in meiosis

Question 35

genetic mutation that causes trisomy-21

Answer 35

aneuploidy - extra chromosome 21

Question 36

genetic mutation that causes large and brilliantly colored flowers

Answer 36

polyploidy

Question 37

genetic mutation that causes sickle cell anemia

Answer 37

base pair substitution

Question 38

humane genome

Answer 38

our genetic material. consists of 3 billion base pairs and 30000 genes.

Question 39

junk DNA

Answer 39

97% of DNA and does not code for proteins. some are regulatory sequences that control gene expression

Question 40

recombinant DNA

Answer 40

taking DNA from two sources and combining them in one cell. used for genetic engineering or biotechnology

Question 41

restriction enzymes

Answer 41

cut DNA at recognit9ion sites, they are molecular scissors. they cut DNA into restriction fragments.

Question 42

gel electrophoresis

Answer 42

separates large molecules of DNA based on their rate of movement across agarose gel in an electric field. small molecules move faster.

Question 43

preparation of gel electrophoresis

Answer 43

DNA is cut by restriction enzymes into small enough pieces to be run across the gel.

Question 44

polymerase chain reaction

Answer 44

cell-free automated technique where a piece of DNA can be rapidly copied. this DNA can then be used to study or compare with other samples