Chap 20: Molecular Genetics

Question 1

Where is DNA found?

Answer 1

mitochondria and chloroplasts

Question 2

Why is DNA important?

Answer 2

it carries genetic information in cells.
can duplicate itself, allowing cell division.

Question 3

Which side do the organelles come from?

Answer 3

Maternal

Question 4

Every cell has DNA EXCEPT

Answer 4

red blood cell

Question 5

How does DNA replicate itself?

Answer 5

using RNA primers

Question 6

What is mRNA used as a messenger for?

Answer 6

protein synthesis

Question 7

What does DNA code for?

Answer 7

amino acids

Question 8

What is Chargaff’s Rule?

Answer 8

• nitrogenous bases make up the “steps” or “rungs” in the DNA ladder.
• nitrogenous bases are not in equal amounts.

Question 9

took pictures of DNA (double helix) using x-rays. mixed DNA with water to find nitrogenous bases on the inside and the sugar/phosphate outside.

Answer 9

Rosalind Franklin

Question 10

expert in crystallizing DNA

Answer 10

Maurice Wilkins

Question 11

produced a structural model of DNA

Answer 11

Watson & Crick

Question 12

What forms the backbones in DNA?

Answer 12

sugar and phosphate

Question 13

What forms the rungs in DNA?

Answer 13

nitrogenous bases

Question 14

What are the bonds in DNA made of?

Answer 14

hydrogen bonds

Question 15

What makes a nucleotide?

Answer 15

deoxyribose, phosphate, nitrogenous base

Question 16

What does antiparallel mean?

Answer 16

parallel strands but run in opposite directions

Question 17

What is semi-conservative DNA?

Answer 17

consists of one strand of old DNA and one strand of newly synthesized DNA

Question 18

What does helicase do?

Answer 18

it unzips the double helix by breaking the hydrogen bonds between the bases.

Question 19

What do single-stranded binding proteins do?

Answer 19

they bind to the newly exposed DNA strands preventing the hydrogen bonds from re-forming and keeps the strands apart.

Question 20

Where does helicase begin unzipping the double helix?

Answer 20

at the replication origin.

Question 21

How does DNA polymerase know where the starting point is?

Answer 21

an RNA primer is attached to the template and guides the enzyme to the starting point.

Question 22

What does DNA polymerase do?

Answer 22

it adds complementary nucleotides to the growing strands, using the exposed strands of the parent DNA as a template.

Question 23

In what direction is DNA built?

Answer 23

5 prime to 3 prime.

Question 24

How is the leading strand built?

Answer 24

continuously. 5 prime to 3 prime.

Question 25

How is the lagging strand built?

Answer 25

formed in short fragments starting from an RNA primer.

Question 26

Why are RNA primers not in DNA?

Answer 26

because the DNA polymerase cuts out the RNA primers and replaces them with appropriate DNA nucleotides.

Question 27

What glues the nucleotides together?

Answer 27

an enzyme called ligase.

Question 28

What is a replication fork?

Answer 28

the point at which the two strands of DNA are separated to allow replication for each strand.

Question 29

What are proteins made of?

Answer 29

they are made of a long chain of specific sequences of amino acids.

Question 30

What two major steps need to happen to make proteins?

Answer 30

transcription and translation

Question 31

What is transcription?

Answer 31

it transcribes the DNA into mRNA

Question 32

What is translation?

Answer 32

code is translated into proteins

Question 33

Why is RNA different from DNA?

Answer 33

RNA leaves the nucleus the backbone is ribose it has uracil instead of thymine its single-stranded

Question 34

Why do we need to make proteins?

Answer 34

structure, hormones, storage, repair

Question 35

Who proposed the "Central Dogma"?

Answer 35

Crick

Question 36

What is the "Central Dogma"?

Answer 36

its a theory that states that genetic information flows only in one direction, from DNA to RNA, to protein, or RNA directly to protein.

Question 37

How is the DNA code transcripted?

Answer 37

mRNA reads DNA code and carries the code to cytoplasm (ribosomes) where proteins are made

Question 38

What is a codon?

Answer 38

they are three bases that code for one amino acidd

Question 39

What happens in the initiation stage of transcription?

Answer 39

RNA polymerase binds to the promotor, then the RNA polymerase separates the DNA strands

Question 40

What is a sense strand?

Answer 40

the side that is to be copied

Question 41

What happens in the elongation stage of transcription?

Answer 41

the sense strand acts as a template, and the polymerase builds an RNA molecule - which is the same except with uracil.

Question 42

What happens in the termination stage of transcription?

Answer 42

the stop signals and then they release the single-strand mRNA.

Question 43

Where does the mRNA go after transcription?

Answer 43

it moves to a ribosome in the cytoplasm

Question 44

What happens in the initiation stage of translation?

Answer 44

subunits join around mRNA and complete it. AUG starts protein synthesis.

Question 45

What happens in the elongation stage of translation?

Answer 45

the tRNA side contains an anti-codon that matches with the mRNA codon. they are joined by peptide bonds.

Question 46

What happens in the termination stage of translation?

Answer 46

a terminator codon turns off the translation.

Question 47

How does tRNA work?

Answer 47

it has a cloverleaf 3-D structure that includes one end holding a specific amino acid and another end with the anti-codon that complements the codon on mRNA

Question 48

What is a gene?

Answer 48

a code for specific proteins made of many amino acids

Question 49

What is a genome?

Answer 49

the complete set of genes in an organism

Question 50

Which mutations are not inherited?

Answer 50

somatic mutations

Question 51

Which mutations are inherited

Answer 51

germ line mutations

Question 52

What is phylogeny?

Answer 52

the proposed evolutionary history of a species

Question 53

What is a mutagen?

Answer 53

any agent that causes genetic mutations

Question 54

Gene splicing/engineering

Answer 54

genetic information from one organism is cut out into the chromosome of another.

Question 55

What do restriction enzymes (endonucleases) do?

Answer 55

they cut DNA at specific nucleotide sequences.

Question 56

What does transgenic mean?

Answer 56

change in genes - usually from another species.

Question 57

What is genetic screening?

Answer 57

testing parents before conception

Question 58

What is amniocentesis?

Answer 58

sampling amniotic fluid

Question 59

Gene therapy (recombinant DNA)

Answer 59

adding proper gene if its defective or missing