L2 Basic Concepts I

Question 1

What is DNA?

Answer 1

deoxyribose nucleic acid

Question 2

What are the components of DNA?

Answer 2

• thin (2nm diameter)
• linear polymer fiber
• double-stranded helix
• 4 nucleobases
• anti-parallel

Question 3

What are the 4 nucleobases in DNA?

Answer 3

• Adenine
• Thymine
• Guanine
• Cytosine

Question 4

How many hydrogen bonds does an adenine-thymine bond have?

Answer 4

2 hydrogen bonds

not as strong as guanine-cytosine bond

Question 5

How many hydrogen bonds does a guanine-cytosine bond have?

Answer 5

3 hydrogen bonds

Question 6

What is a genome?

Answer 6

• a genome is an organism’s complete set of DNA including all of it’s genes
• Each genome contains all of the information needed to build and maintain that organism.

Question 7

How many DNA base pairs is in a copy of the human genome?

Answer 7

more than 3 billion DNA base pairs

In humans, a copy of the entire genome is contained in all cells that have a nucleus

Question 8

How many genes are the in the human genome?

Answer 8

21,000

Question 9

What is a gene?

Answer 9

• a gene is a sequence of DNA or RNA which codes for a molecule that has a function
• basic physical and functional unit of heredity

Question 10

What are protein coding genes?

Answer 10

Genes that are expressed to be proteins.

20,000 genes found in the human genome

Question 11

What is the final product of noncoding genes?

Answer 11

RNA

Question 12

What is the function of transfer RNAs (tRNA)?

Answer 12

Transfer amino acids to the RNA template to make proteins

Question 13

What are ribosomal RNAs (rRNA)?

Answer 13

the RNA component of ribosome

Question 14

What is the function of microRNAs (miRNA)?

Answer 14

• play a very important role in regulating protein-coding gene expression

Question 15

How do you read family based assignments?

Answer 15

CYP3A4

• first number (3) –> gene family
• second letter (A) –> subfamily
• third number (4) –> gene number

Question 16

On average, how many exons are there per gene?

Answer 16

8.8 exons per gene

Question 17

On average, how many introns are there per gene?

Answer 17

7.8 introns per gene

Question 18

What is a locus?

Answer 18

The nucleotide’s unique position in the reference genome

Question 19

What is chromatin?

Answer 19

• unwound DNA with protein
• observed through interphase
• DNA is accessible for transcription

Question 20

What is a chromosome?

Answer 20

• tightly packed DNA
• observed only during cell division (metaphase)
• DNA is not used

Question 21

What is the central dogma?

Answer 21

• expression of genetic information
• DNA is transcribed into RNA which is then translated into proteins

Question 22

Why are there chromosome pairs?

Answer 22

one set from mom; one set from dad

Question 23

How does coronavirus replicate?

Answer 23

RNA replication

Question 24

What is transcription?

Answer 24

• DNA to RNA
• mRNA maturation process

Question 25

What is translation?

Answer 25

- RNA to protein

Question 26

What does a protein always start with?

Answer 26

AUG (methionine)

Question 27

How many codons and amino acids are in the genetic coding system?

Answer 27

- 64 codons - 20 amino acids

Question 28

What are sequence variations?

Answer 28

polymorphisms - whether a variation has a functional consequence depends on its location and nature | most occur in intron region so it has no effect

Question 29

What is a polymorphism?

Answer 29

- a sequence variation at the **same position of homologous chromosomes** (diploid genome) | there are no polymorphism in the genome of a single germ cell (haploid genome)