L8: DNA AND THE FLOW OF GENETIC INFO

Question 1

What is the real word for DNA?

Answer 1

Deoxyribonucleicacid

Question 2

DNA lives…

Answer 2

inside the nucleus

Question 3

Amino acids live…

Answer 3

outside the nucleus in the cytoplasm

Question 4

Characteristics of the structure of DNA

Answer 4

• double helix

Question 5

What scientist discovered the structure of DNA?

Answer 5

Watson and Crick

Question 6

What are the two strands called in DNA and what are they held together by?

Answer 6

• nucleotides
• held together by base pairing - hydrogen bonds

Question 7

Differences in DNA sequence lead to …

Answer 7

genetic variation

Question 8

When is DNA replicated?

Answer 8

-during the cell cycle in S phase

Question 9

Whats the first thing that happens when DNA is being replicated?

Answer 9

-hydrogen bonds are broken.
- uncoils

Question 10

Whats the name of the protein/ enzyme that replicates DNA?

Answer 10

DNA polymerase

Question 11

What does DNA polymerase do to replicate the DNA?

Answer 11

The enzyme adds the nucleotides using the sequence of the parent strand

Question 12

What is an old strand of DNA referred to as?

Answer 12

template strand

Question 13

Can mistakes be made during the DNA replication process?

Answer 13

Yes, there called DNA
- errors
-mismatches
-mutations

Question 14

Whats the error rate of DNA replication?

Answer 14

1 in 10,000 nucleotides

Question 15

What rate has DNA polymerase reduced the error rate to?

Answer 15

1 in 10 000 000 000 nucleotides

Question 16

What is a mismatch error?

Answer 16

occurs when the proofreading abilities of DNA polymerase fails
Example: c matches with a

Question 17

Does a cell have the ability to fix a mismatch error?

Answer 17

-yes
- with the mismatch repair enzymes

Question 18

When do we see a DNA mutation?

Answer 18

When the mismatch repair was not able to be fixed.

Question 19

What is a DNA mutation?

Answer 19

A permanent error in the DNA sequence

Question 20

What are the 3 steps in DNA repair?

Answer 20

1. recognition
2. removal
3. replacement

Question 21

How can a segment of DNA become damaged? Cause mutations?

Answer 21

• chemicals
• radiation
• ultraviolet light

Question 22

Explain the stages of DNA repair:

Answer 22

Recognition- the damaged or mismatched area is detected
Removal- the region is removed by enzymes, cuts out damaged area
Replace- DNA polymerase fills in the gap with new nucleotides, by re-reading and filling the template strand

Question 23

Why is it important to repair either mutations or damaged DNA?

Answer 23

• if you have failed DNA mechanisms it can result in disease

Question 24

Whats an example of a disease that can result from failed DNA mechanisms?

Answer 24

• xeroderma pigmentosum
• more prone to skin cancer
• if they are exposed to ultraviolet light it will cause two T”s that are side by side to bond together, creating thymine dimers

Question 25

What do genes code for ?

Answer 25

ribonucleic acid molecules

Question 26

What info makes a protein?

Answer 26

RNA molecules

Question 27

What is a gene?

Answer 27

A sequence of DNA that is used to make a copy of an RNA molecule used to eventually make proteins

Question 28

BLANK --> BLANK ---> BLANK --->

Answer 28

DNA -> RNA -> Protein

Question 29

Differences with RNA compared to DNA

Answer 29

- single-stranded -the base uracil takes the place of thymine - ribose sugar is used

Question 30

3 types of RNA molecules:

Answer 30

1. ribosomal RNA = rRNA 2. messenger RNA= mRNA 3. transfer RNA = tRNA

Question 31

Function of mRNA:

Answer 31

the code that specifies the order of amino acids that are used to make proteins

Question 32

Function of rRNA:

Answer 32

- a major component of ribosomes - their job is to make covalent bonds that link the amino acids together

Question 33

Function of tRNA:

Answer 33

- transports the correct amino acid to the ribosome using the information found on the mRNA molecule - brings it to the site of amino acid assembly

Question 34

What are the two steps of making proteins?

Answer 34

1. transcription 2. translation

Question 35

Transcription

Answer 35

-produces mRNA copy from the DNA sequence of a gene - once made the mRNA moves from the nucleus to the cytoplasm

Question 36

Translation

Answer 36

- assembles the amino acids of proteins

Question 37

Transcription begins when...

Answer 37

RNA polymerase binds to a region of DNA called a promoter

Question 38

What two things do you need for transcription to occur?

Answer 38

1. DNA sequence of a gene 2. RNA polymerase

Question 39

Transcription starts at the ------ and ends at the --------

Answer 39

promoter region, terminator sequence

Question 40

Transcription

Answer 40

-mRNA Polymerase finds promoter, begins unzipping DNA and reading the template strand and adding the complimentary nucleotides

Question 41

End point of transcription:

Answer 41

Terminator sequence

Question 42

How is transcription different from DNA replication?

Answer 42

- only one strand of DNA is used in as a template - the product is a single-stranded RNA, not double stranded - specific segments are transcribed into RNA not the entire DNA molecule - transcription occurs all the time

Question 43

Transcription occurs ----- the time while DNA replication only happens during -----

Answer 43

all the time, cell division

Question 43

What has to happen after transcription before translation?

Answer 43

the RNA molecule needs to move from inside the nucleus to the cytoplasm

Question 44

Formula of Translation

Answer 44

mRNA into proteins

Question 45

A group of three nucleotides are called...

Answer 45

codons

Question 46

What do we used to make sense of the meaning of codons?

Answer 46

We can use the genetic code.

Question 47

What is the genetic code?

Answer 47

A chart that specifies all the codons needed to make certain proteins

Question 48

T/F : more then one codon can code for a single amino acid.

Answer 48

True

Question 49

What codon is the starting point for mRNA translation?

Answer 49

AUG - METHIONINE

Question 50

What is the stop codon for mRNA translation:

Answer 50

UAA UAG UGA

Question 51

What does a stop codon symbolize?

Answer 51

the end of translation

Question 52

What four things do you need for the construction of a protein?

Answer 52

1. The mRNA molecule 2. Ribosomes: made up of rRNA and proteins 3. amino acids 4. tRNA molecules: that will bring the amino acids to the mRNA and ribosomes

Question 52

A tRNA molecule is really just a ....

Answer 52

RNA molecule folded on its self

Question 53

What important aspect does the tRNA molecule bring to translate?

Answer 53

the anti codon

Question 54

What is the anticodon?

Answer 54

a codon complimentary to the original codon

Question 55

Example of DNA mutation

Answer 55

-Sickle-cell anemia -caused by a single nucleotide mutation in the hemoglobin gene