Unit 4 - DNA

Question 1

What is DNA?

Answer 1

A molecule that carries genetic information in a cell

Question 2

What is the monomer of DNA?

Answer 2

A nucleotide

Question 3

What is a nucleotide made of?

Answer 3

• Phosphate
• Sugar (deoxyribose)
• Base

Question 4

What bases can a nucleotide be made of?

Answer 4

• Adenine
• Thymine
• Guanine
• Cytosine

Question 5

What is complementary base pairing? What does this mean in terms of bases?

Answer 5

It means that bases will always pair up with the same bases:
- Adenine and Thymine will always pair up
- Guanine and Cytosine will always pair up

Question 6

How is DNA formed? What is its structure described as?

Answer 6

Nucleotides join together to form two longs strand of DNA, which then join together through hydrogen bonds that connect the complementary bases together. This structure is described as a double helix

Question 7

Where is DNA found (eukaryotic cells)?

Answer 7

In chromosomes, which are found in the nucleus.

Question 8

What are chromosomes made up of?

Answer 8

DNA molecules and proteins

Question 9

What are genes?

Answer 9

Stretches of DNA that code for a trait/characteristic

Question 10

How would you describe the genetic code? (2 words)

Answer 10

Universal and redunant

Question 11

What does DNA code for?

Answer 11

Proteins

Question 12

What determines what protein DNA codes for?

Answer 12

The order of bases

Question 13

What is a codon?

Answer 13

Three letter base sequence that codes for a specific protein

Question 14

Why is the genetic code considered redundant?

Answer 14

There are 20 amino acids but with a three letter base sequence, there are 64 possible codons (4 bases to the power of three). There are more codons than needed.

Question 15

What are mutations?

Answer 15

Irreversible changes to the genetic code

Question 16

Why are mutations usually very harmful? What/who do they harm the most?

Answer 16

The are harmful because they change the codon sequence which will produce either a dysfunctional protein or the wrong protein.
They can severely impact your gametes and your future offspring.

Question 17

What is the name for something that causes a mutation? Give examples of these causes:

Answer 17

Mutagen:
- UV light
- Radiation
- Chemicals

Question 18

What are the three types of mutations? Which is the least harmful?

Answer 18

• Substitution
• Deletion
• Addition
  Substitution is the least harmful because it doesn’t affect the rest of the following genetic sequences.

Question 19

What is a chromosome?

Answer 19

A structure made out of DNA and proteins that carries genetic information in the form of genes.

Question 20

What base is different in an RNA strand?

Answer 20

Thymine turns into urasil

Question 21

What is an allele?

Answer 21

An alternative form of a gene

Question 22

What is a locus?

Answer 22

The location of a particular gene

Question 23

What is a phenotype?

Answer 23

The physical appearance of an organism

Question 24

What is evolution?

Answer 24

A change in phenotype

Question 25

What is a telomere?

Answer 25

A stretch of non-coding DNA found at the end of a chromosome that protects the chromosome from damage during cell division

Question 26

What are some factors that cause ageing?

Answer 26

- Decline of mitochondria function - Genetic damage - Shortening of telomeres - Decrease in stem cell quantity - Lack of protein control due to harmful substance build up

Question 27

What is parkinsons disease?

Answer 27

A progressive neurological brain disease where brain cells that produce dopamine are damaged

Question 28

What are the symptoms of parkinson's?

Answer 28

- tremors - stiffness - changes in speech

Question 29

What are the cures/preventions of parkinsons?

Answer 29

- No cure - Deep brain stimulation mimics cells that have been damaged - Some medecines help slow the progress of the disease - aerobic exercise might help

Question 30

What is the cause of parkison's?

Answer 30

There is no known cause

Question 31

What are the 6 stages of evolution?

Answer 31

1. Variation + overpopulation 2. Change in environment 3. Struggle for existence 4. Survival of the fittest 5. Increased heritability 6. Change in phenotype