DNA and RNA

Question 1

what is the genome

Answer 1

Entire genetic material in an organism

Question 2

What does both DNA and RNA stand for and what do they both do

Answer 2

DNA - Deoxyribonucleic acid
RNA - Ribonucleic acid
- found in all living cells
- Both needed to build proteins
- information - carrying molecules

Question 3

What is the function of DNA and RNA

Answer 3

DNA - stores genetic information
- contains instructions for growth and development

RNA - Transfers the genetic code from DNA out of the nucleus and carries it to the ribosomes

Question 4

What are DNA and RNA made up of and what is it formed from

Answer 4

Made up of repeating units called nucleotides

nucleotides are formed from :
- A pentose sugar (5 carbon atoms)
- Nitrogen containing organic base
- A phosphate group

Question 5

What are the components of a DNA nucleotide

Answer 5

• Deoxyribose sugar with a hydrogen at carbon 2
• A phosphate group at carbon 5
• 1 of 4 nitrogenous groups - adenine (a), cytosine (c), guanine (g), thymine (t)

Question 6

what are the components of an RNA nucleotides

Answer 6

• A ribose sugar with a hydroxyl group at carbon 2
• Phosphate group
• 1 of 4 nitrogenous groups - adenine (a), cytosine (c), guanine (G), and uracil (u) instead of thymine

Question 7

How are the nitrogenous bases found

Answer 7

2 structural forms purines and pyrimidines
- purines = 2 rings (adenine, guanine)
- Pyrimidines = 1 ring (thymine/uracil, cytosine)

Question 8

How do you form a polynucleotide

Answer 8

• Joined via a condensation reactions
• Occur between the phosphate group of one nucleotide and pentose sugar of the next
• forms a phosphodiester bond due to there being 2 ester bonds
• Chain of altering phosphate and pentose sugars are sugar-phosphate backbones

Question 9

why are there 2 ester bonds in a polynucleotide and what do you call them

Answer 9

There are 2 ester bonds (phosphodiester) because there is
- one binding the 5th carbon from the pentose sugar to the phosphate group
- The second is binding the phosphate group to the pentose sugar of the next nucleotide

Question 10

what is the structure of DNA

Answer 10

2 polynucleotide (chains made from phosphodiester bonds) side by side which are anti-parallel

Question 11

what is the structure of each polypeptide strand of DNA

Answer 11

Said to have a 3 carbon and a 5 carbon end as the strands are anti-parallel one is known ad the 5 to 3 strand where the 5 is at
the top and t
other the 3 to 5 strand

Question 12

How are the 2 strands of DNA held together

Answer 12

Held together by hydrogen bonds between nitrogenous bases
A-T = 2 hydrogen bonds
C-G = 3 hydrogen bonds

Question 13

why do the bases A and T and then G and C always bind together

Answer 13

Because one is a purine and one is a pyrimidine meaning they are the right length for stable DNA

Question 14

what bases are purines and what bases are pyrimidines

Answer 14

purines = A and G pyrimidines = C and T/U

Question 15

who was DNA first discovered by and when

and what did he name it

Answer 15

• First observed by Swiss scientist Friedrich Miescher in 1800s
• He named it nuclein and defined it as a molecule in 1869

Question 16

What did scientists doubt about DNA in the 1800s and why

Answer 16

They doubted it could carry the genetic code because :
- it has a relatively simple chemical composition as only composed of 3 parts
- It was hypothesised genetic material was carried by proteins as it has a more complexed chemistry

Question 17

What happened in the 1940s in the structure of DNA

Answer 17

1940s - Role of DNA in genetic inheritance began to be researched and understood

Question 18

what happened in 1953 in the discovering in the structure of DNA

Answer 18

It was confirmed DNA carried genetic codes
- it was understood despite only having 4 nucleotides the use of the triple code (A,T,T) enabled variation
- DNA protected in the nucleus enables security of genetic code rather that proteins in the cytoplasm’s susceptible to hydrolysis

Question 19

what did Watson and crick do in 1953

Answer 19

Watson and crick confirmed the double-helix structure using Rosalind franklins X-ray DNA

they also came up with a model by which DNA might be replicated the theory was called semi-conservative DNA replication

Question 20

How do the bases in DNA stabilise the structure

Answer 20

They form hydrogen bonds between the nitrogenous bases A+T and C+G stabilise the structure as many hydrogen bonds provide strength