Lecture 18-19: Nucleic Acids

Question 1

Functions of Nucleic acids (3)

Answer 1

1. Genetic material
2. Gene expression
3. Gene regulation

Question 2

Characteristics of genetic material

Answer 2

1. Carry information
2. Can be replicated
3. Can be transmitted to offspring
4. Can be changed by mutation

Question 3

Information carried by genetic material

Answer 3

1. genes
2. info to regulate gene expression
3. directions for DNA replication

Question 4

Where is genetic material found?

Answer 4

DNA

Question 5

Gene

Answer 5

units that encode polypeptides (and other products)

Question 6

What are the two types of RNA

Answer 6

1. non-coding RNA
2. transfer RNA

Question 7

What is said to be and “intermediate” between DNA and protein? Why?

Answer 7

mRNA

DNA-like: perform key function in info processing

Protein-like: functions as a catalytic molecule

Question 8

What do you call an RNA that performs catalytic functions

Answer 8

a ribozyme

Question 9

What happens during splicing in RNA processing?

Answer 9

The introns (non-coding parts of RNA) removed and exons (coding) joined tgt

Question 10

Exceptions to the central dogma of gene expression

Answer 10

1. Many genes encode functional RNA (non-coding RNA) and are used directly (don’t follow the process)
2. some genes encode protein subunits which need to be combines with others to function
3. reverse transcription: when info flows from RNA to DNA

Question 11

Name the pyrimidines

Answer 11

cytosine, uracil (RNA), thymine (DNA)

Question 12

Name the purines

Answer 12

guanine, adenine

Question 13

Which is larger, pyrimidines or purines

Answer 13

purines

Question 14

Components of nucleic acid

Answer 14

1. phosphate group
2. nitrogenous base
3. 5-carbon sugar

Question 15

What is the direction of the sugar-phosphate backbone of nucleic acids?

Answer 15

nucleic sequence written in 5’->3’ direction (nucleic acids added to 3’ end)

Question 16

Between RNA and DNA, which is more chemically active? Why?

Answer 16

RNA; more chemical groups exposed

Question 17

Between RNA and DNA, which has a more complex highest level of structure?

Answer 17

RNA: 3º - 4º level

needed for its “protein-like” functions

Question 18

Between RNA and DNA, which can store genetic information?

Answer 18

both

Question 19

What are chromosomes made of?

Answer 19

condensed chromatin wrapped around histone

Question 20

What are the two types of chromatin in a resting cell?

Answer 20

euchromatin: loosely packed, make up active regions of genome

heterochromatin: densely packed, inactive regions of genome

Question 21

Why is DNA compact and condensed in the metaphase?

Answer 21

1. prevent damage
2. promote proper distribution

Question 22

Why is (some) DNA loosely packed as chromatin fibers during the interphase?

Answer 22

DNA needs to be accessible for DNA replication and gene expression

Question 23

What are the epigenic modifications? What is another way of calling this?

Answer 23

DNA methylation

Histone methylation / acetylation

Chromatin remodelling

Question 24

What is chromatin remodelling for?

Answer 24

regulate gene expression

Histone acetylation to open chromatin (activate)

Histone/DNA methylation to close chromatin (deactivate)

Question 25

Who found the "transforming theory"

Answer 25

Griffith in 1928

Question 26

Who first found evidence that the "transforminf substance" is DNA?

Answer 26

Avery, McCarty & MacLeod in 1944

Question 27

Who found more evidence that viral genes are DNA?

Answer 27

Hershey and Chase in 1952

Question 28

Functions DNA technology

Answer 28

1. isolate and amplify DNA sequences (DNA cloning) 2. Analyze DNA sequences 3. Modify DNA sequences 4. Perform transgenesis

Question 29

What are the tools and techniques used in DNA technology?

Answer 29

1. Restriction enzymes 2. Vectors 3. Gel electrophoresis

Question 30

What are the two types of vectors?

Answer 30

Cloning vector: transfer DNA in host cells and replicate it Expression vector: expresses gene form cloned DNA in host cell

Question 31

Give 3 examples of vectors

Answer 31

1- plasmids 2- viruses 3- artificial chromosomes

Question 32

Name two applications of DNA technology

Answer 32

1. DNA cloning 2. Restriction Fragment length polymorphism (RFLP)

Question 33

What are the two main goals of DNA cloning?

Answer 33

1. Produce large amounts of a specific gene 2. Expressing cloned genes to produce encoded protein

Question 34

What are the two main goals of RFLP?

Answer 34

1. identify a genotype 2. identify genetic markers

Question 35

Name examples of DNA cloning to produce large amounts of a specific gene

Answer 35

* Cloned genes provide enough DNA for DNA sequencing. The sequence of a gene can help us understand how a gene works and identify mutations that cause diseases. * Cloned DNA can be used as a probe to identify the same gene or similar genes in other organisms.

Question 36

Name examples of DNA cloning to express cloned genes to produce encoded proteins

Answer 36

* Large amounts of the protein can be purified to study its structure and function. * Cloned genes can be introduced into bacteria or livestock to make pharmaceutical products such as insulin. * Cloned genes can be introduced into plants and animals to alter their traits. * Cloned genes can be used to treat diseases—a clinical approach called gene therapy.