B14 - Variation and Evolution

Question 1

What do genomes code for?

Answer 1

An entire organism

Question 2

What was Charles Darwin’s idea of ‘survival of the fittest’

Answer 2

Natural selection as the fittest individuals would survive and reproduce

Question 3

Charles Darwin’s theory of natural selection took a long time to be accepted. As of now, it has been proven lots of times.

What are some examples it has been proven?

Answer 3

Development of antibiotic resistance in bacteria
Fossil records

Question 4

Why do all multicellular, eukaryotic organisms require a continuous supply of new cells?

Answer 4

For growth, development and repair

Question 5

What are the three main stages of the cell cycle?

Answer 5

Growth
DNA replication + mitosis
Division

Question 7

Why do we call gametes haploid cells?

Answer 7

Because they have half the genetic material of a normal cell

Question 8

What are diploid cells?

Answer 8

Cells that contain two sets of genetic information (one from each parent)

Question 9

What are maternal chromosomes?

Answer 9

Chromosomes from the mother

Question 10

What are paternal chromosomes?

Answer 10

Chromosomes from the father

Question 11

What is the first step of meiosis?

Answer 11

The cells replicates all its DNA
The chromosomes line up into 23 pairs and then divides into 2 daughter cells

Question 12

What shape does the original and replicated chromosome make?

Answer 12

They form a symmetrical X-shape

Question 13

Why is the DNA different in each cell divided by meiosis?

Answer 13

The left to right order is random so there is trillions and trillions of combinations

Question 14

What is the second step of meiosis?

Answer 14

The chromosomes line up along the centre of the cell
The opposite symmetrical arms of each chromosome are pulled to each side of the cell to divide again

This creates 4 daughter cells

Question 15

How many chromosomes does each daughter cell have after the first division

Answer 15

23 chromosomes each

Question 16

How many chromosomes does each daughter cell have after the second division?

Answer 16

23 chromosomes again

Question 17

What is different about the 4 daughter cells from one cell in meiosis?

Answer 17

They are all genetically unique

Question 18

What can we call the 4 genetically unique daughter cells in meiosis?

Answer 18

Gametes

Question 19

What are the two main ways organisms can reproduce?

Answer 19

Sexual reproduction
Asexual reproduction

Question 20

What is fertilisation in terms of gametes?

Answer 20

The fusion of male and female gametes

Question 21

When plants reproduce with the fusion of Egg cells and Pollen cells, is it sexual or asexual reproduction?

Answer 21

Sexual reproduction

Question 22

In asexual reproduction, all the offspring are _______

Answer 22

Identical

Question 23

How do eukaryotic organisms (like plants, fungi and few animals) asexually reproduce?

Answer 23

Through mitosis

Question 24

How do prokaryotic organisms (like bacteria) asexually reproduce?

Answer 24

Binary fission

Question 25

What are the main benefits of asexual reproduction?

Answer 25

- Only one parent is needed - process is very quick

Question 26

Only one parent is needed for asexual reproduction and the process is very fast. Why would this be a benefit?

Answer 26

It allows a single organism to quickly colonise a new area

Question 27

What are the drawbacks of asexual reproduction?

Answer 27

- no genetic variation - less chance or adapting to new conditions

Question 28

Why is no genetic variation a drawback for asexual reproduction?

Answer 28

Reduced gene pool would mean when theres a disease, theres a high risk all offspring could die

Question 29

What is the main advantage of sexual reproduction?

Answer 29

Lead to high genetic variation

Question 30

What are the short term and long term benefits of sexual reproduction allowing genetic variation?

Answer 30

Short term: population is less likely to get wiped out by a new disease Long term: allows evolution - the population can adapt to changing conditions

Question 31

What is the main disadvantage of sexual reproduction?

Answer 31

Takes more time and energy for the animals to impress and find their mate

Question 32

What are the steps you should follow when drawing a genetic diagram?

Answer 32

Parents Phenotype Parents Genotype Gametes Genotype Punnet Square Offsprings Genotype Offsprings Phenotype

Question 34

What is embryo screening?

Answer 34

Testing embryos from IVF to see if they have inherited genetic disorders

Question 35

What are the pros of embryo screening?

Answer 35

- helps prevent the suffering of the offspring - saves money on treating the offspring's disorder

Question 36

What are the cons of embryo screening?

Answer 36

- Implies people with genetic disorders are not wanted - in the future, people can start screen for other traits like eye colour, physique and gender

Question 37

What is selective breeding?

Answer 37

Where you take the best plants/animals in a population and breed them together in the hope of getting a desired offspring

Question 38

How long has selective breeding been a method farmers used?

Answer 38

For 1000's of years

Question 39

What are the disadvantages of selective breeding?

Answer 39

It reduces the gene pool of the population which leads to inherited disorders and higher risk of diseases Less variation which could lead to a wipe out from disease

Question 41

What is genetic engineering?

Answer 41

Taking a gene from an organism with a desirable characteristic and transfer it to another organism

Question 42

Whats another way of saying genetic engineering?

Answer 42

Genetically modifying

Question 43

What are the pros of genetically modified crops?

Answer 43

More fuits Resistant to disease Produce special nutrients for developing countries

Question 44

What are the cons of genetically modified crops?

Answer 44

We don't know for certain if they affect our health These better plants could outcompete other plants and completely change the ecosystem

Question 45

How do we actually transfer a gene from one organism to another? (genetic engineering)

Answer 45

Find the gene you want and cut the section of DNA out using enzymes Insert the gene into a vector like a virus and introduce it to the organism The organism willb start producing the same proteins and take on the characteristic

Question 46

What is tissue culture?

Answer 46

When cells are grown into a new organism

Question 47

Describe how you would carry out selective breeding.

Answer 47

Seclect your two best organisms with the best desirebale characteristics. Breed them together in hopes of getting offspring with even better characteritsics. Breed the offspring together and then repeat this for generations to come