ch. 12 and 13

Question 1

Describe Griffith’s experiment.

Answer 1

• He experimented on bacteria that causes pneumonia. He heated a harmful strain then injected it into a mouse, and it wasn’t a toxin. Then a heat killed harmful and harmless strain were injected and the mouse lived. He figured out bacteria passed genes to their offspring.

Question 2

Describe Avery’s experiment.

Answer 2

• He repeated Griffith’s experiment in 1949, but his goal was to determine what molecule was involved in the transformation. He used various enzymes to destroy different molecules within the bacteria. He discovered that DNA contains the information that is passed from one generation to the next.

Question 3

Describe Hershey & Chase’s experiment.

Answer 3

• Hershey & Chase conducted an experiment to discover what part of the virus entered the bacteria. They grew viruses in cultures containing radioactive isotopes: phosphorus -32 and sulfur -35 (this way they could trace the DNA (32P) and the protein coat (35S))
• They determined that it was the DNA that entered the bacteria

Question 4

Distinguish between the Lytic and Lysogenic cycles.

Answer 4

• Lytic Cycle: Viral DNA hijacks cell; makes more viruses instead of bacteria. Turns cell into virus. Makes as many viruses as it can (hijacks the ribosomes); Cell will lyse (explode) when it can’t make any more viruses. Lyses go to other cells & make more viruses.
• Lysogenic Cycle: Virus raids host cell & injects DNA. Doesn’t hijack, but instead hides out in the cell and goes off after making cells and waiting for the right moment to release its cell into the lytic cycle and releases thousands of cells as opposed to one. Can make cells for years. Triggers can be random. High temperature and sickness often trigger.

Question 5

Distinguish between purines and pyridimines.

Answer 5

purines- contain 2 carbon rings (A,G)

pyrimidines- contain 1 carbon ring (C,T)

Question 6

What was Chargraffs contribution to the discovery of DNA?

Answer 6

He discovered that the % of G and C were almost equal in and DNA sample, same for A and T.

Question 7

What was Wilkins and Franklins contribution to the discovery of DNA?

Answer 7

They worked independently with X-ray diffraction, which helped determine DNA is a double helix.

Question 8

Who finally determined the structure of DNA?

Answer 8

Watson and Crick

Question 9

What is the shape of DNA?

Answer 9

double helix (twisted ladder)

Question 10

Describe the structural components of DNA (backbone, rungs)

Answer 10

backbone- consists of alternating sugar phosphate

rungs- nitrogenous bases

Question 11

Describe the process of DNA replication.

Answer 11

1-DNA is unzipped by helicase which breaks up hydrogen bonds in several locations called replication bubbles
2-DNA polymerase attaches to the old strand and plugs in the base pairs (3’ to 5’ end) [antiparallel] One daughter strand gets copied in a more continuous piece (leading strand) and the other gets copied in fragments called Okazaki fragments (lagging strand) They are later linked together by DNA ligase.
3-another DNA polymerase correct any mistakes. telomerase copies telomeres (segments of non-coding RNA found at the end of strands.

Question 12

What is a replication bubble?

Answer 12

“unzipped” part of DNA (broken hydrogen bonds)

Question 13

What is a replication fork?

Answer 13

the hundreds of places along the DNA in which eukaryotic chromosome replication takes place

Question 13

what is the subunit (monomer) of RNA?

Answer 13

nucleotides

Question 15

What is the subunit (monomer) of RNA?

Answer 15

nucleotides

Question 16

How is RNA different from DNA?

Answer 16

RNA -

• is single stranded instead of double stranded
• contains ribose instead of deoxyribose
• contains uracil instead of thymine

Question 17

List the 3 types of DNA involved in protein synthesis and their functions.

Answer 17

messenger RNA- copies the recipe from DNA so proteins can be made
transfer RNA- transfers amino acids to ribosome
ribosomal RNA- makes up ribosomes

Question 18

Describe the shapes of each of the 3 RNA molecules.

Answer 18

mRNA- single stranded helix
tRNA- single stranded hair pin shape
rRNA- single stranded globular

Question 19

Describe the process of transcription.

Answer 19

In the nucleus, RNA polymerase creates the mRNA. mRNA copies the recipe from DNA. RNA polymerase binds to the promoter and plugs in the complementary base pairs until the end sequence is reached.

Question 20

What is an Intron and an Exon?

Answer 20

intron-non-coding sequences of DNA that are not part of the recipe
Exon- coding sequences of DNA that are expressed

Question 21

Describe RNA processing.

Answer 21

when mRNA is formed both the introns and exons are copied. before mRNA leaves the nucleus, the introns are removed and the exons are spliced back together. mRNA then carries the recipe to the ribosome

Question 22

Describe the process of translation.

Answer 22

on the ribosome, mRNA attaches to the small subunit. The tRNA have anticodons to pair up with codons of mRNA. Aug is the start at the P site. another tRNA attaches to the next codon at the a site. A peptide bond forms between the amino acids then mRNA shifts over. original tRNA leaves through the E site. process is continued until stop codon is reached

Question 23

What is a codon?

Answer 23

3 nucleotides which code for a specific amino acid

Question 24

What is an anticodon?

Answer 24

on the tRNA they pair up with mRNA codons

Question 25

What is a telomere?

Answer 25

segments of noncoding DNA found at the end of the strands (copied by telomerase)

Question 26

Describe how prokaryotes regulate gene expression different,y from eukaryotes.

Answer 26

prokaryotes- have opens and operators

eukaryotes- have TATA boxes and use transcription factors

Question 27

What is an operon?

Answer 27

a group of genes that work together

Question 28

What is an operator?

Answer 28

sequence of nucleotides in front of the lac operon

Question 29

What is a TATA box?

Answer 29

sequence of 30 nucleotides that binds a protein that helps RNA polymerase attach to the promoter

Question 30

What is the purpose of enhancer sequences?

Answer 30

they loop DNA to bring transcription factors together to regulate gene expression

Question 31

What are transcription factors?

Answer 31

they regulate gene expression in many ways

Question 32

How does the coiling of eukaryotic DNA influence gene expression?

Answer 32

it doesn’t allow RNA polymerase to perform transcriptions, genes that are coiled can’t be expressed

Question 33

What are some other no transcriptional ways genes can be controlled in eukaryotes?

Answer 33

attract/block RNA polymerase
uncoil areas of DNA so genes are accessible
controlling mRNA leaving nucleus
manipulating the stability of RNA
breaking down proteins

Question 34

Why is eukaryotic gene regulation more complex than prokaryotes?

Answer 34

eukaryotes are multicellular with different genes being expressed in different types of cells

Question 35

How is micro RNA created and what is it used for?

Answer 35

they are small segments of RNA cut into segments

they destroy RNA with complementary sequence

Question 36

What is differentiation?

Answer 36

during embryonic development cells become specialized

Question 37

What is the function of a hox gene?

Answer 37

they code for transcription factors that activate other genes

Question 38

How can a leg grow where an antennae should be?

Answer 38

mutations in the hox genes can cause a mutation bc the transcription factor can activate another gene

Question 38

What is a bacteriophage?

Answer 38

A virus that infects bacteria.

Question 39

How can the environment influence differentiation?

Answer 39

it can be sped up or changed by cues such as food availability, temperature, population size

Question 40

What type of bond holds the 2 strands of DNA together?

Answer 40

Hydrogen bonds.

Question 41

Describe helicase and give its function.

Answer 41

Helicase is an enzyme which breaks the hydrogen bonds in several locations called replication bubbles.

Question 42

How do you know something’s an enzyme?

Answer 42

If it ends in “ase”

Question 43

List the 4 enzymes involved in DNA replication and describe the function of each.

Answer 43

• Helicase: breaks the hydrogen bonds in several locations called replication bubbles.
• DNA polymerase: attaches to the old strands and “plugs in” the appropriate base pairs.
• DNA ligase: links together the lagging strand and the leading strand.
• Telomerase: copies telomeres.

Question 44

Where are proteins made?

Answer 44

In the ribosomes.

Question 45

Where do transcription and translation take place?

Answer 45

Transcription takes place in the nucleus while translation takes place on the ribosome.

Question 46

Describe what has to occur to make the ribosome functional.

Answer 46

During translation, once protein is made, it goes to the golgi body. This allows the large subunit to attach making the ribosome functional.

Question 47

Describe the E, P, and A of EPA.

Answer 47

• A: delivering Amino Acids
• P: Proteins being made
• E: Empty transfer RNA goes here so it can Exit to get another one

Question 48

Be able to label a bacteripohage, the structure of DNA (one phosphate group, 5 deoxyribose sugar, nitrogenous base), and tell the difference between messenger RNA (single squigly line), transfer RNA (mall directory), and ribosomal RNA (the other one)

Answer 48

yeet luv Michael Palermo (you’re all welcome for these fantastic flash cards i know luv my fans)

Question 49

What is the subunit/monomer of DNA?

Answer 49

nucleotide