Topic 6 - Inheritance, Variation and Evolution (1)

Question 1

DNA:
What is DNA and what does it stand for?

Answer 1

• DNA stands for deoxyribonucleic acid
• it is the chemical that all of the genetic information in a cell is made up from
  (it contains coded onformation - the instructions to put an organism together and make it work)

Question 2

DNA:
What does your DNA control?

Answer 2

what inherited characterisics you have

Question 3

DNA:
Where is DNA found?

Answer 3

In the nucleus of plant and animal cells, in really long structures called chromosomes

Question 4

DNA:
What are chromosomes?

Answer 4

Really long structures of DNA

Question 5

DNA:
How are chromosomes usually found?

Answer 5

in pairs

Question 6

DNA:
Describe the basic structure of DNA

Answer 6

• DNA is a polymer
• It’s made from two strands coiled together in the shape of a double helix

Question 7

DNA:
What is a gene?

Answer 7

A small section of DNA found on a chromosome

Question 8

DNA:
What does each gene code for (tell the cells to make)?

How many amiono acids are used in this process?

Answer 8

a particular sequence of amino acids which are put together to make a specific protein

• only 20, but they make up thousands of different proteins

Question 9

DNA:
What can DNA also determine about a cell?

Answer 9

what preoteins a cell produces (haemoglobin, keratin)
this in turn determines what type of cell it is e.g. red blood cell, skin cell

Question 10

DNA:
What is a genome?

Answer 10

the entire set of genetic material in an organism

Question 11

DNA:
Name 3 ways that understanding the human genome is important for science and medicine

Answer 11

1) it allows scientists to identify genes in the genome that are liked to different types of diseases
2) knowing which genes are linked to inherited diseases could help us to understand them better and possibly develop effective teatments for them
3) Scientist can look at genomes to trace the migration of certain populations of people around the world. All modern humans are descended from a common ancestor who lived in Africa, but humans can now be found all over the planet. The human genome is mostly identical in all induviduals, but as different populations migrated away from africa, they gradually developed tiny differences in their genomes. By investigating these differences, scientists can work out when new populations split off in a different direction and what route thet took

Question 12

DNA STRUCTURE AND PROTEIN SYNTHESIS:
What is a DNA strand made up of?

Answer 12

DNA strands are polymers made from repeating units called nucleotides

Question 13

DNA STRUCTURE AND PROTEIN SYNTHESIS:
What does a nucleotide consist of?

Answer 13

a sugar, a phosphate group and one base

Question 14

DNA STRUCTURE AND PROTEIN SYNTHESIS:
What forms the ‘backbone’ of a DNA strand?
How is it structured?

Answer 14

The sugar and the phosphate groupd in the nucleotides
The sugar and phosphate groups alternate
One of the four different bases joins to each sugar

Question 15

DNA STRUCTURE AND PROTEIN SYNTHESIS:
What is each side of a base touching?

Answer 15

The base links to a sugar on one strand and avbase on the opposite strand of the helix

Question 16

DNA STRUCTURE AND PROTEIN SYNTHESIS:
What bases pair with each other?

Answer 16

Adenine - Thymine
Guanine - Cytosine

Question 17

DNA STRUCTURE AND PROTEIN SYNTHESIS:
What does the order of bases in agene determine?

Answer 17

the order of amino acids in a protein

Question 18

DNA STRUCTURE AND PROTEIN SYNTHESIS:
How is each amino acid coded for?

Answer 18

by a sequence of 3 bases in the gene

Question 19

DNA STRUCTURE AND PROTEIN SYNTHESIS:
What do the amono acids join to form?

Answer 19

to make various proteins (depending on the order of the gene’s bases)

Question 20

DNA STRUCTURE AND PROTEIN SYNTHESIS:
What is the function of the parts of DNA that don’t code for proteins?

Answer 20

some of theses non-codingmparts switch genes on and off, so they controll whether or not a gene is expressed (used to make a protein)

Question 21

DNA STRUCTURE AND PROTEIN SYNTHESIS:
Where are proteins made?

Answer 21

in the cell cytoplasm on tiny structures called ribosomes

Question 22

DNA STRUCTURE AND PROTEIN SYNTHESIS:
What do ribosomes need on order to make proteins?

Answer 22

ribosomes use the code in the DNA to make proteins
(this is found in the nucleus and can’t move out because it is really big, so the cell needs to get the code from the DNA to the ribosome)

Question 23

DNA STRUCTURE AND PROTEIN SYNTHESIS:
How does a cell get the code from the DNA to the ribosome?

Answer 23

Using a molecule called mRNA - which is made by copying the code from DNA
The mRNA acts as a messenger between the DNA and he ribosome - it carries code between the two

Question 24

DNA STRUCTURE AND PROTEIN SYNTHESIS:
How are the correct amino acids brought to the ribosomes?

Answer 24

they are brought to the ribosomes in the correct order by carrier molecules

Question 25

DNA STRUCTURE AND PROTEIN SYNTHESIS: What happens when a chain of amino acids has been assembled?

Answer 25

it folds into a unique shape which allows the protein to perform the task it is meant to do

Question 26

DNA STRUCTURE AND PROTEIN SYNTHESIS: Give 3 examples of proteins in the body?

Answer 26

1) ENZYMES - act as biological catalysts which speed up chemical reactions in the body 2) HORMONES - used to carry messages around the body e.g. insulin is a hormone released into the blood by the pancreas to regulate blood sugar level 3) STRUCTURAL PROTEINS - are physically strong e.g. collagen is a structural protein that strengthens connective tissues (like ligaments and cartilage)