life at molecular, cellular and tissue level

Question 1

What are the two types of acids that are found in cells?

Answer 1

the two acids are DNA and RNA

Question 2

What does DNA stand for?

Answer 2

Deoxyribonucleic acid

Question 3

What does RNA stand for?

Answer 3

Ribonucleic acid

Question 4

Where is DNA mainly found ?

Answer 4

It is found in the nucleus of a cell, where it forms a part of the chromosomes that make up the chromatin network

Question 5

Who discovered important information with regards to the structure of DNA?

Answer 5

Francis Crick and James Watson began to study the structure of DN in the late 1950s at Cambridge University while Maurice Wilkins and Rosalind Franklin were conducting studies with regards to the structure of DNA in London. Rosalind Franklin was the one who discovered the double helix shape of the DNA through the use of x-ray diffraction images. She died but Watson, Wilkins and Cricks received the Nobel Price

Question 6

What shape is the DNA?

Answer 6

The DNA is made of a 3D double helix shape

Question 7

What is a nucleotide?

Answer 7

A nucleotide is a building block ( of the DNA ) which is made of a phosphate, sugar and a base.

Question 8

What are the four bases which are found in DNA?

Answer 8

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

Question 9

How do the bases pair up and how many hydrogen bonds join together each base?

Answer 9

Adenine matches with Thymine ( 2 hydrogen bonds) while Cytosine matches Guanine ( 3 hydrogen bonds). The hydrogen bonds are however very weak

Question 10

How is the double helix made up?

Answer 10

the double helix is made up of alternating sugar and phosphate links . The bonds between the sugar and phosphate are strong

Question 11

Where are the base pairs attached?

Answer 11

They are attached to the sugar molecules

Question 12

What are the 3 functions of DNA?

Answer 12

1 It codes genetic information in every cell
2 it can replicate ( through the process of replication)
3 it makes proteins ( protein synthesis)

Question 13

What is the process of replication?

Answer 13

The process in which a new DNA molecule is made, from an existing one. The new DNA molecule will be identical to the original one

Question 14

Why is replication necessary ?

Answer 14

Replication is necessary in order to pass down genetic information to the new daughter cells which are formed during cell division

Question 15

How does replication take place?

Answer 15

1 The enzyme polymerase catalyses the process
2 The DNA begins to unwind
3 The weak hydrogen bonds between the bases break
4 The DNA unzips
5 The free nucleotides which are found in the cytoplasm go to the DNA strand to pair up with their matching base
6 Adenine matches to Thymine while Cytosine matches to Guanine
7 The process occurs until the two strands separate completely , forming new strands which are both identical

Question 16

What are the differences between the RNA and DNA?

Answer 16

RNA is a single strand while DNA is a double strand
RNA has ribonucleic acid while DNA has deoxyribose sugar
RNA is short while DNA is long
RNA has uracil which matches with adenine while DNA has thymine
RNA bases : Uracil and Adenine, Cytosine and Guanine while DNA has Thymine and Adenine, Cytosine and Guanine

Question 17

What are the three types of RNA?

Answer 17

messenger RNA
transfer RNA
ribosomal RNA

Question 18

how is mRNA formed?

Answer 18

mRNA is formed through the process of transcription

Question 19

How does transcription take place?

Answer 19

1 DNA unwinds and unzips
2free nucleotides found in the nucleoplasm match with their complimentary bases on one DNA strand
3 mRNA strand is formed
4 the mRNA strand breaks away
5 the DNA begins to re-zips
6 the mRNA strand leaves the nucleoplasm through a pore found in the nuclear membrane
7 the mRNA strand goes and attaches itself to the ribosome found in the cytoplasm
8 transcription ends when the mRNA strand becomes attached to the ribosome

Question 20

What happens after the transcription phase?

Answer 20

1 The tRNA molecule, with it’s anticodon, goes and attaches itself to it’s matching amino acid, also found in the cytoplasm ( the anticodon will be the opposite of the codon)
2 the tRNA molecule then returns to the mRNA strand and attaches itself to the codon
3 A second tRNA molecule will find it’s matching amino acid and return to the mRNA and to it’s codon
4 The amino acid of the first and second tRNA molecule will become attached to each other, through a peptide bond.
5 Once the amino acids are connected, the first tRNA molecule will move away from the mRNA strand and find it’s matching amino acid once again while more tRNA molecules will join the mRNA strand
6 The process occurs until a protein is formed ( a protein needs to have 50 amino acids or more)

Question 21

Why is DNA fingerprinting so important?

Answer 21

It allows us to :

• diagnose deceases which have been inherited. This can be done before birth or after birth and is therefore very important. It allows parents to make essential decisions with regards to pregnancy
• it can be used to solve crimes.DNA can provide accurate meanings of identification and is therefore very accurate. traces of DNA which have been left on a crime scene can often provide the identity of the criminal
• allows for the establishment of paternity