4 - DNA and chromosomes

Question 1

what is a bacteriophage?

Answer 1

a bacteriophage (informally, phage) is a virus that infects and replicates within a bacterium.

Question 2

what is the most common type of DNA type?

Answer 2

the most common DNA type is B-DNA.

Question 3

what is type A-DNA?

Answer 3

A-DNA found in dehydrated cells. shorter and fatter structure is thought to protect DNA in extreme conditions.

Question 4

what types of DNA have a right hand helix?

Answer 4

both A- and B-DNA have a right handed helix.

Question 5

what is Z-DNA?

Answer 5

Z-DNA, a transient form, is left handed.

Question 6

what is DNA?

Answer 6

a polymer containing hereditary genetic information to pass on to next generation.

Question 7

what is DNA tightly coiled around into a chromosome?

Answer 7

proteins

Question 8

where is DNA located?

Answer 8

eukaryotes - inside nucleus and mitochondria

prokaryotes - in cytoplasm

Question 9

what is an organisms complete set of DNA known as?

Answer 9

its genome

Question 10

how many genes does mitochondrial DNA consist of?

Answer 10

mitochondrial DNA consists of 37 genes which are essential for normal mitochondrial functions.

some encode for enzymes, others for transfer RNAs and ribosomal RNAs, which are essential for translation.

Question 11

a DNA monomer is known as a nucleotide. what does it consist of?

Answer 11

a phosphate group

a sugar molecule

a nitrogenous base
- Adenine
- Thymine
- Cytosine
- Guanine

Question 12

what is a chain of nucleotides called?

Answer 12

polynucleotide

Question 13

how many nucleotides does a haploid human genome have

Answer 13

The haploid human genome has ~ 3 x 10^9 nucleotides (in 23 chromosomes)

Question 14

what is the sugar in the backbone of RNA

Answer 14

ribose

Question 15

what is the backbone of DNA

Answer 15

2’ - deoxyribose

Question 16

what links to nucleotides in the 5’ of the sugar molecule to form a nucleotide?

Answer 16

a phosphate group

Question 17

what created a phosphodiester link?

Answer 17

Links to the sugar molecule of adjacent nucleotide on the 3; carbon creating a phosphodiester link

Question 18

what do the sugar-phosphate groups of the nucleotide form?

Answer 18

the backbone of DNA

Question 19

what pairs with Thymine

Answer 19

Adenine

2H bonds

Question 20

what pairs with Cytosine

Answer 20

Guanine

3H bonds

Question 21

are DNA strands parallel or anti-parallel

Answer 21

strands are anti-parallel

direction starts with the 5’ sugar carbon and ending with 3’ carbon.

Question 22

what does base pairing do?

Answer 22

base pairing stabilises the parallel helix structure of DNA.

provides the mechanism through which DNA replicates and is transcribed

Question 23

…

Answer 23

the outer edges of the bases are exposed and available for potential hydrogen bonding as well.

provides easy access to the DNA for other molecules, including the proteins that play vital roles in the replication and expression of DNA.

Question 24

…

Answer 24

DNA is transcribes to RNA, RNA is translated to protein.

Question 25

what does Adenine pair with in RNA?

Answer 25

Uracil

Question 26

...

Answer 26

“Most cells in the body are diploid… that makes a total of 6 billion base pairs of DNA per cell. Because each base pair is around 0.34 nm long, each diploid cell therefore contains about 2 m of DNA. Moreover, it is estimated that the human body contains about 50 trillion cells— which works out to 100 trillion meters of DNA per human. Now, consider the fact that the Sun is 150 billion meters from Earth. This means that each of us has enough DNA to go from here to the Sun and back more than 300 times, or around Earth's equator 2.5 million times!

Question 27

what is DNA wound around?

Answer 27

proteins called histones.

Question 28

what is a complex of DNA wound around 8 histones called?

Answer 28

a nucleosome