Unit 1 : DNA

Question 1

4 stages of hypothesis for the formation of the 1st cell

Answer 1

1. abiotic (non living) synthesis of small organic molecules
2. small molecules into macromolecules
3. packaging of molecules into protocells (prokaryotic cells)
4. origin of self replicating molecules

Question 2

Describe the Miller - Urey Experiment

Answer 2

they created an experiment to see if water vapor cooled our oceans and wanted to see what was in it and to see if it was possible that macromolecules could be formed

Question 3

What is a protocell?

(lipids and other molecules?)

Answer 3

May have been fluid filled vesicle
- they lipids and other molecules can form vesicles formation

Question 4

What can increase the rate of vesicle formation? What substrate?

Answer 4

adding clay can increase the rate of vesicle

Question 5

What properties of life vesicles can exhibit?

Answer 5

• simple growth
• reproduction
• metabolism
• maintenance of internal environment

Question 6

Why is RNA the 1st genetic material and not DNA?

Answer 6

Due to hypothesis protocells were able to form on earth and they grew and split and passed RNA to their “daughters” and RNA can replicate itself and not DNA

Question 7

What catalyzes different reaction?

Answer 7

ribozymes

Question 8

Why is it important that earth has a reducing atmosphere?

Answer 8

due to the lack of oxygen and other gases and vapors, which prevents oxidation,

Question 9

What did morgans group showed ?

Answer 9

showed genes are located on chromosomes and made of DNA and held together by proteins.

Question 10

How was the role of DNA 1st discovered?

Answer 10

discovered by studying bacteria and viruses that can infect them.

Question 11

Griffith Experiment

Answer 11

• worked with two strains of bacteria (pathogenic, harmless)
• transformation: the strains could change it self

Question 12

What did Avery, Mccarty, and MacLeod established?

Answer 12

20 years later they affirmed griffith experiment
- you can transform cells with just DNA and change behavior

Question 13

Pathogenic vs. Harmless strains of bacteria

(Griffith Experiment)

Answer 13

(S strain) Pathogenic: smooth - body doesn’t recognize it (deadly) pneumonia
(R starin) Harmless: rough - body attacks it (not deadly)

Question 14

Hershey - Chase

Answer 14

• they used viruses to see if it was protein or DNA, which has sulfur
• showed that DNA is the genetic material of the T2 phage (virus)

Question 15

Double Helix

Answer 15

• franklin and wilkins discovered that DNA was a double helix
• franklin concluded that 2 sugar phosphate backbones with nitrogenous bases

Question 16

Franklin, Watson, Cricket,

Answer 16

• franklin discovered double helix in DNA
• watson and cricket formed a model of double helix (leaked info from franklin)

Question 17

Translation

mRNA

in cytoplasm

Answer 17

process in which the information encoded in a strand of mRNA is used to construct a protein
- where tRNA & mRNA work together to make polypeptide
happens in the cytoplasm and ribosomes are involved (eukaryotic cells)

Question 18

Transcription

tRNA

in nucleous

Answer 18

making mRNA using info in DNA
- (DNA directed synthesis of RNA)
- strand of DNA is used as a template for the manufacture of a strand of pre-mRNA

Question 19

Polypeptide

Answer 19

1 small bead from translation = 1 amino acids

Question 20

tRNA vs mRNA

definition

Answer 20

tRNA - transfer (role in protein synthesis, translation)
mRNA - messenger

Question 21

Primary transpict

Answer 21

initial RNA transcript from any gene prior to processing (pre mRNA)

Question 22

Promoter, TATA Box

Answer 22

TATA box - a lot of thymine & adenine
- tata box must bind to DNA before RNA polymerase can bind in the right position
Promoter - DNA of a gene that binds to RNA polymerase

Question 23

RNA polymerase

Answer 23

breaks DNA strands apart and join together the RNA nucleotides
- the promoter starts transcribing a gene for RNA polymerase

Question 24

DNA template strand

Answer 24

read it from 3 prime to 5 prime
- nucleotides in RNA sequence

Question 25

Codon Strand | mRNA

Answer 25

read it from 5 prime to 3 prime - same sequence as mRNA but T instead of U - codon

Question 26

RNA processing | definition

Answer 26

pre mRNA to mRNA - enzymes modify pre mRNA before its sent off to cytoplasm - slicing - happening in nucleus

Question 27

5' cap

Answer 27

sequence of nucleotides that are going to get added to the 5 prime end of mRNA - where ribosome is going to attach

Question 28

poly-A-tail

Answer 28

- added on 3 prime end (adenine) - poly-A-tail protects mRNA

Question 29

modifications for 5' cap & poly-A-tail

Answer 29

export of mRNA to cytoplasm - enzymes can break the bond between nucleotides - helps ribosomes attach to the 5' end. - we need mRNA out - protect RNA - ribosome to bind to RNA to start translation

Question 30

Exons & Intron

Answer 30

exons - exit the nucleus intron - stay in nucleus will not be apart of the final translation process

Question 31

Spliceosome

Answer 31

- proteins make spliceosomes - cut out introns

Question 32

Ribozymes

Answer 32

RNA molecules that function as enzymes and can splice RNA

Question 33

alternative RNA splicing

Answer 33

some genes can encode more than one kind of polypeptide

Question 34

Transfer RNA | (tRNA)

Answer 34

translating mRNA into protein - tRNAS transfer amino acids to polypeptides in a ribosomes

Question 35

Anticodons | tRNA

Answer 35

base-pairs with codon on mRNA

Question 36

A site / P site / E site

Answer 36

A site - holds tRNA that carries to the next animo acid (do i fit in with the codons) P site - tRNA carries the polypeptide chain E site - exit site tRNAs leave the ribosomes

Question 37

operon model

Answer 37

- bacteria type of regulation of groups of genes

Question 38

operator

Answer 38

switch is a segment of DNA

Question 39

operon | bacteria

Answer 39

includes operator, promoter, and genes they control - it can be switched off by a protein called repressor

Question 40

repressor

Answer 40

bound to tryptophan, then binds to dna to turn off and blocks RNA polymerase transcription | if repressor is binded RNA polymerase cant transcript

Question 41

regulatory gene

Answer 41

located some distance from the operan

Question 42

tryptophan | (trp)

Answer 42

is an amino acids, operon is on - trp is turned off by REPRESSOR if tryptophan is making too much

Question 43

*lac*

Answer 43

bacteria breaks down lactose because bacteria likes glucose (sugar) - catabolic - wont turn on unless lactose is around | breaks things down

Question 44

cyclic AMP | (cAMP)

Answer 44

cAMP activates protein CRP - CRP binds to promoter of lac operon which increases RNA polymerase accelerating transcription - when glucose starts to leave cAMP and CRP increases the rate of trancription and translation to make more enzyme and break down lactose at a faster rate | positive gene regulation turning up the volume

Question 45

Chromatic modification | 1st step in gene expression in eukaryotic cells ## Footnote histone acetylation, DNA methylation

Answer 45

histone acetylation - loosens chromatin structure promoting the start of transcription DNA methylation - with reduced transcription, causes long term inactivation of genes in cellular differiation ## Footnote nucleosomes

Question 46

Transcription Regulation | 2nd step in gene expression in eukaryotic cells

Answer 46

transcription factors - needs help from RNA polymerase to start transcription some bind to tata box (promoter region) - when the start is complete RNA polymerase can begin to move along the templagte strand - activators (protein) bind to enhancers (DNA)

Question 47

RNA proccesing | 3rd step in gene expression in eukaryotic cells

Answer 47

- alternative RNA splicing (introns) - RNA segmants treated as exons

Question 48

Protein degration (protesomes) | 4th step in gene expression in eukaryotic cells

Answer 48

- once protein made in cytoplasm gets tagged by ubiqutin - protein enters proteosomes - when non more needed ubiqutin gets recycled