Structure of DNA

Question 1

What is the essence of DNA?

Answer 1

DNA is a molecule that holds instructions for growth and development in every living thing

Question 2

What is the shape of DNA and how is it held together?

Answer 2

Double-Stranded Helix, with complimentary base pairs

Question 3

What are the basic units of DNA?

Answer 3

Nucleotides

Question 4

What do the basic units of DNA consist of?

Answer 4

Deoxyribose sugar, phosphate and base

Question 5

What do all basic units (nucleotides) have in common?

Answer 5

All nucleotides are identical except from the base

Question 6

What are the bases and how do they pair together?

Answer 6

Adenine and Thymine (A-T), Guanine and Cytosine (G-C)

Question 7

What do these basic units (nucleotides) do with each other when forming a DNA strand?

Answer 7

The basic units are linked together via strong covalent bonds between the deoxyribose sugar of one nucleotide and the phosphate of another nucleotide, forming a strong sugar-phosphate back bone

Question 8

What are the ends of a DNA strand called?

Answer 8

5’ end (said 5 prime end) at the phosphate end, and the 3’ end at the deoxyribose end

Question 9

How do the two DNA strands run in relation to each other and how do they bind together?

Answer 9

Anti-parallel, so one strand runs 5’ to 3’ and the other runs 3’ to 5’, this forms the twisting double helix shape we see, the two strands are linked together via weak hydrogen bonds between the bases

Question 10

How do all cells store their genetic information?

Answer 10

In the base sequence of DNA

Question 11

What is determined by the sequence of bases?

Answer 11

The Genotype

Question 12

What is DNA present in?

Answer 12

Every living thing

Question 13

What does the organisation of DNA differ in?

Answer 13

Different types of organisms

Question 14

What two groups can we put DNA into based on the way they organise themselves?

Answer 14

Eukaryotes and Prokaryotes

Question 15

What are Prokaryotes?

Answer 15

Bacteria

Question 16

What is different about the prokaryote cell’s nucleus and DNA?

Answer 16

They do not have a membrane bound nucleus and their DNA is free in the cytoplasm

Question 17

How are the genes held in a prokaryote cell?

Answer 17

They have a singular circular chromosome in the centre of the cell that holds all the genes needed for that bacterium

Question 18

What are plasmids and what has them?

Answer 18

Additional circles of DNA, bacteria prokaryotes

Question 19

What are Eukaryotes?

Answer 19

Animals, plants and fungi

Question 20

What is different about the eukaryote cell’s nucleus and DNA?

Answer 20

It has a membrane bound nucleus and their chromosomes are linear rather than circular, however in some cells small circular genetic information can additionally be found

Question 21

How is DNA stored in eukaryotes in the nucleus?

Answer 21

The DNA found in linear chromosomes within the nucleus is tightly coiled around special proteins called histones

Question 22

What organism is a eukaryote but has plasmids like a prokaryote?

Answer 22

Yeast cell

Question 23

Where does the numbering start on the carbons in a nucleotide sugar and in what direction?

Answer 23

from the point where the base is connected and clockwise

Question 24

What is the name of the detail of all the organelles inside a living cell?

Answer 24

An Ultrastructure

Question 25

What organelles are found in both animal and plant cells?

Answer 25

Nucleus, cell membrane, cytoplasm, mitochondria and ribosome

Question 26

What does the Nucleus do?

Answer 26

Contains genetic information and controls all cell activities

Question 27

What is the site of protein synthesis?

Answer 27

Ribosome

Question 28

What is the site of photosynthesis?

Answer 28

Chloroplast

Question 29

What do chromosomes do?

Answer 29

Chromosomes contain genetic information that gives rise to a organism’s characteristics

Question 30

How is the phosphate group usually represented?

Answer 30

Dramatically as a small circle