Cells/Cell evolution

Question 1

What is the endosymbiotic theory and list 4 pieces of evidence to support it.

Answer 1

• It’s a theory that eukaryotic cells evolved from prokaryotes.

1. Mitochondria/Chloroplasts have double membranes
2. Mitochondria/Chloroplasts have their own DNA
3. Mitochondria/Chloroplasts are similar size to prokaryotes.
4. Mitochondria/Chloroplasts have 70s ribosomes (same as prokaryotes)

Question 2

evidence that viruses may have evolved from cells?

Answer 2

1. some viruses have genes found in cellular organisms
2. Viruses may have evolved from free-living cells.
3. Some viruses have enzymes that synthesize DNA from RNA (same as eukaryotes)
4. Some viruses have similar material to (parasitic bacteria)

Question 3

binomial system of classification

Answer 3

• globally recognized
• classifys organisms into groups based on common ancestry/DNA
• every species has a binomial name
  -members of the same species can produce fertile offspring
  -genus written first + capitalized, followed by species in lowercase

Question 4

thermoregulation

Answer 4

• normal body temperature is 37
• thermo-receptors detect temperature change
• conscious/behavioural actions to prevent temperature extremes (e.g wearing more or less clothing)
• message gets sent to the hypothalamus —> pituitary gland.
• releases TSH
• thyroxin controls metabolic rate
• shivering to generate heat
• vasoconstriction/vasodilation

Question 5

temperature and enzymes.

Answer 5

Increase temp, increase rate of motion.
Increased frequency of collisions.
Watch increases rate of reaction.
Until optimum temp. Higher temp = denatured.

Question 6

Thermal properties of air + water

Answer 6

water = high specific heat capacity
air = lower.

water requires more energy to change temperature.
Water is a more stable habitat.
Water is a good coolant

Question 7

mutations + cancer

Answer 7

Mutations = random changes in the DNA
- may involve addition, deletion, substitution, etc.
- mutations in tumor suppressor genes = oncogenes.
- uncontrolled cell division
- divide repeatedly to form tumors

Question 8

mutations + evolution

Answer 8

new phenotypes

increase variation

new phenotypes = better chances of survival

advantageous mutations live longer

and thus more chance of reproduction

and mutated genes get passed down

allele frequencies change in population (over time)

evolution. consequence of natural selection.