Lesson 1

Question 1

What is the central dogma of genetics

Answer 1

Genetic information flows from DNA → RNA → proteins

Question 2

What is the study of stable phenotypic changes that do not involve alterations in the DNA sequence

Answer 2

Epigenetics

Question 3

What does epigenetics most often involve

Answer 3

Changes that affect gene activity and expression

Question 4

What can the poly A tail be compared to in genes

Answer 4

A dress → they can express them differently in different tissues

Question 5

Is dna replication faster In bacteria or mammals

Answer 5

Bacteria

Question 6

Why is dna replication faster in bacteria?

Answer 6

There are no chromatin, nucleosomes, and chromosomes but only a circular double strand dna (does not need to be unfolded)

Question 7

What are the two types of antibodies

Answer 7

Polyclonal and monoclonal

Question 8

How are polyclonal antibodies obtained?

Answer 8

By injecting the antigen into an animal and then isolating them

Question 9

How are monoclonal antibodies obtained?

Answer 9

By hybridomas: antibody-producing B cells fused with myeloma cells

Question 10

Besides the use of antibodies, what is another way to study proteins?

Answer 10

Proteomics: allows us to have a full picture of proteins produced by a tissue

Question 11

If a psendogene expresses a protein, it is not a psendogene but a:

Answer 11

Gene

Question 12

What are housekeeping proteins?

Answer 12

Constitutive proteins that are required for the maintenance of basic cellular functions: they are expressed in all cells

Question 13

Housekeeping proteins represent what percentage of the total protein mass of a cell?

Answer 13

75%

Question 14

What is one key reason it is easier to analyze DNA / RNA compared to proteins?

Answer 14

They can be hybridized → proteins do not have a complimentary strand

Question 15

What are the main technologies used to analyze mRNA?

Answer 15

Differential hybridization
Subtractive hybridization
Differential display
Expressed sequence tag (EST)
Serial analysis of gene expression (Sage)

Question 16

What mRNA technology is used to identify genes that are expressed in one type of cell but not another → ex: normal vs. cancer cells

Answer 16

Differential hybridization

Question 17

What are the two pitfalls of the differential hybridization method?

Answer 17

It is not possible to detect most genes (low sensitivity) and there is a lot of redundancy in sequences (genes that are more expressed are going to occupy most of the plaque)

Question 18

Which approach in analyzing gene expression involves the subtraction of a test DNA sample from a reference DNA sample → a tumor cell from a normal cell?

Answer 18

Subtractive hybridization

Question 19

In which mRNA analysis method is mRNA extracted from normal cells and reverse transcribed into cDNA, amplified by PCR, and then ran on a polyacrylamide gel next to cDNA for the tumor cell mRNA

Answer 19

Differential display

Question 20

What is the main use for an EST test when analyzing mRNA?

Answer 20

Can be used as probes to detect whether or not a gene is expressed

Question 21

When using SAGE a short sequence of DNA / RNA contains sufficient information to uniquely identify what?

Answer 21

A transcript and to locate a sequence in the genome

Question 22

When using SAGE, sequence tags can be linked together to form what?

Answer 22

Long serial molecules that can be cloned and sequenced

Question 23

What does the quantitation of the number of times a particular tag is observed mean in SAGE?

Answer 23

Provides the expression level of the corresponding transcript

Question 24

Describe how microarrays are used to analyze mRNA:

Answer 24

The mRNA of 2 different cells is transformed into a single cDNA tagged with fluorescent dye and combined to hybridize microarrays counting thousands of known gene sequences

Question 25

What are some issues found with microarray analysis?

Answer 25

Sensitivity and range (signals saturate very quickly) and it is difficult to Keep track of the identity of all cDNA