Final Study Guide Deck

Question 1

What are 2 strands of DNA held together by

Answer 1

Hydrogen bonds

Question 2

How many hydrogen bonds are between G and C

Answer 2

3

Question 3

How many hydrogen bonds between A and T

Answer 3

2 ( that’s why there is a TATA box at the beginning of Transcription- break apart the A-T double bond bc its weaker than G-C triple bond)

Question 4

Nucleoside vs Nucleotide

Answer 4

Nucleoside: Sugar and base
Nucleotide: Sugar, Base, Phosphate group

Question 5

What are the purines and what are the pyrimidines

Answer 5

Purines: A/G (double ringed)
Pyrimidines: C and T, U (single ringed)

Question 6

What are 3 structural features of DNA

Answer 6

• Right handed double helix, antiparallel, complementary

Question 7

Which enzyme seperates the 2 strands of DNA during replication

Answer 7

Helicase

Question 8

Which enzyme makes the RNA primer

Answer 8

Primase

Question 9

Difference between DNA polymerase 1 and DNA polymerase 3

Answer 9

1: Removes DNA primers
3: Adds DNA bases 5’–>3’

Question 10

What are telomeres

Answer 10

At the end of the chromosomes, prevent gene loss ( In somatic cells, the telomeres shorten whith every dvision. In Stem/Cancer cells, telomerase ensures that telomeres do not shorten).

Question 11

Where is the telomerase gene found

Answer 11

In stem cells and gametes

Question 12

What is a clinical application with telomerase

Answer 12

Premature aging occurs when there is no telomerase.
Telomerase is expressed in 90% of cancers, stimulates cell division.

Question 13

What is Mismatch repair, and which cancer is related to it?

Answer 13

Mismatch repair: One nucleotide is removed by an exonuclease and strand is repaired
Colorectal cancer (lynch syndrome) loss of function in DNA mismatch repair

Question 14

What is nucleotide excision repair and its clinical application

Answer 14

• Remove bulkey DNA lesions (caused by UV light, i.e. skin cancer)
• Xeroderma Pigmentosum is a defect in nucleotide excision, skin cells can’t fix themselves, so early and frequent skin cancers

Question 15

Base excision repair

Answer 15

One or a few bases damaged, corrected easily

Question 16

Double strand break repair and clinical correlation

Answer 16

• Most dangerous- A number of bases are damaged and there is non-homologous end joining, not accurate, and DNA lost in process.
• BRCA 1 associated (Breast Cancer)

Question 17

rRNA function

Answer 17

site of translation, structural and functional components of ribosome

Question 18

tRNA function

Answer 18

transfers amino acid for protein synthesis

Question 19

Common structure of tRNA

Answer 19

cloverleaf

Question 20

mRNA function

Answer 20

template for protein synthesis, carries genetic information from DNA to ribosome

Question 21

What do eukaryotes have in their mRNA that differs from prokaryotes?

Answer 21

Poly- A tai and Cap

Question 22

Enhancer vs silencer at promotor

Answer 22

Enhancer: bound by enhancer-binding transcription factor
Increase the rate of txn

Silencer: Decrease the rate of txn

Question 23

3 steps of transcription in Eukaryotes

Answer 23

Initiation, Elongation, Termination

Question 24

Transcription difference between bacteria and Eukaryotes:

Answer 24

SImilar
Steps: initiation, elongation and termination
Differences:
Euk have 3 different polymerase and bacteria have one
Euk DNA is complexed with proteins

Question 25

Where does splicing occur

Answer 25

in the nucleus ( Introns taken out, exons left in and EXPRESS)

Question 26

Beta Thalassemia is a condition where there is an error in which protein?

Answer 26

Splisosome, there is inproper splicing of the genes.

Question 27

4 steps of protein synthesis

Answer 27

tRNA charging Initiation Elongation Termination

Question 28

Difference between Silent, missense, and nonsense mutations

Answer 28

Silent Changed base results in the same amino acid Missense Changed base codes for a different amino acid Nonsense Changed base becomes a stop codon

Question 29

Describe tRNA charging

Answer 29

Amino acid is transfered to RNA

Question 30

Where does mRNA bind during initiation in prokaryotes?

Answer 30

mRNA binds to small subunit at Shine Dalgarno sequence

Question 31

3 ribosome sites in elongation

Answer 31

A - aminoacyl P- peptidyl E - exit

Question 32

Negative control vs positive control in operons

Answer 32

Negative control: Regulatory protein is a repressor Positive control Regulatory protein is an activator

Question 33

Inducible vs repressible control of an operon

Answer 33

Inducible Transcriptional is usually off Repressible Transcription is usually on

Question 34

What is a negative inducible

Answer 34

Negative control Regulator protein is a repressor Inducible Txn is normally off Something must happen to turn it in

Question 35

What type of control is the LAC operon

Answer 35

Negative control- regulator protein is a repressor (Transcription is normally off, but if glucose is absent AND lactose is present, it is on)

Question 36

Which 3 proteins does the Lac operon induce transcription of when it is on

Answer 36

A, Y, Z

Question 37

Do eukaryotes have operons?

Answer 37

no, not usually. Mostly bacteria.

Question 38

What are heavily methylated regions associated with

Answer 38

repression of transcription

Question 39

Describe restriction endonuclease and its pattern

Answer 39

often in a palindrome, binds and cleaves DNA at restriction sites

Question 40

What do you find with FISH staining

Answer 40

See parts of chromosomes to find abnormalities, use flourescent staining

Question 41

PCR steps

Answer 41

Denaturing Heat up DNA to 95 degrees Celsius Separate dsDNA into single strands Annealing Cool the solution to 50 degrees Celsius Primers anneal to complementary sequences of ssDNA Extension Warmed to 72 degrees Celsius DNA polymerase is active and synthesis strands on 3’OH primer

Question 42

What does Northern Blot examine

Answer 42

mRNA (measures expression)

Question 43

What does ELISA examine

Answer 43

antibodies in the blood

Question 44

Which pattern of inheritance only appears in males

Answer 44

Y-linked

Question 45

Which pattern of inheritance has emales passing onto their offspring, but not males?

Answer 45

Mitochondirial

Question 46

Describe the significance of the P53 gene

Answer 46

Tumor suppressor gene, triggers cell-cycle arrest. Most common genetic change in cancer

Question 47

What is the proto-oncogene and what is the common mutation for cancer?

Answer 47

This gene is responsible for making the cell divide. If defective, the cell will divide continuously, causing cancer.

Question 48

What are oncogenes

Answer 48

mutated version of proto-oncogene, causes cells to grow out of control. Gain of function mutation. RET/MET are examples.

Question 49

Describe the 4 types of aneuploidy

Answer 49

Nullisomy Loss of both membranes of chromosome pair 2n-2 Monosomy Loss of a single chromosome 2n-1 Trisomy Gains of a single chromosome 2n+1 Tetrasomy Gains of two homologous chromosomes 2n+2

Question 50

What chromosome is linked to Down Syndrome

Answer 50

Trisomy on chromosome 21

Question 51

Which disorder commonly accompanies a robertsonian translocation

Answer 51

Down's syndrome- extra part of chromosome 21 is attached to another chromosome

Question 52

Describe Edward's Syndrome dysfunction

Answer 52

Extra chromosome 18 ( not viable pregnancy, die soon after birth. Often born with intestines external to body).

Question 53

Describe Patau syndrome

Answer 53

Extra chromosome 13, average survival of 10 days (not viable).

Question 54

What is the chromosomal abnormality in Klienfelter syndrome

Answer 54

Male with an extra X chromosome (usually sterile, hypogonadism, tall)

Question 55

What is the chromosomal abnormality in Poly X syndrome

Answer 55

3 or more X chromosomes in women Usually benign condition, increases in severity (decreased intelligance with more X's). Increased risk of spontaneous abortions

Question 56

What is the chromosomal abnormality in XYY males

Answer 56

Extra Y chromosome, possible learning disabilities.

Question 57

What is the chromosomal abnormality in Turner's syndrome

Answer 57

XO chromosomes (webbed neck common, broad chest, short stature, hypogondaism).

Question 58

How many Barr bodies in XXYY

Answer 58

1

Question 59

How many Barr bodies in XXXXX

Answer 59

4

Question 60

Angelman vs Prader-Willi syndrome

Answer 60

Angelman: Maternal inheritance is lost on ch 15, inappropriate laughter, developmental delay, neurological symptoms. Prader-Willi: Paternal Inhritance is lost on ch 15, mental handicap, anorexia early in life, obesity later in life.

Question 61

Diseases with genetic anticipation

Answer 61

Huntington's disease, Fragile X syndrome, Friedrich ataxia

Question 62

What is the inheritance pattern of cystic fibrosis

Answer 62

Autosomal recessive

Question 63

What is the pathology in Sickle Cell disease

Answer 63

Point mutation, leads to sickled RBC shape, hypoxia.

Question 64

What is the pathology in Tay-Sach's disease

Answer 64

Mutation on HEXA gene on Chromosome 15 Premature neuron death, progressive degeneration of neurons. Death between 3-4 years in infantile onset, death between 5-15 in juvanile onset.

Question 65

What type of mutation is found in the BRCA 1 gene

Answer 65

DNA damage repair gene (Double strand breaks) not functioning. Activation of P53.