Inheritance, Variation and Evolution

Question 1

What is sexual reproduction?

Answer 1

The fusion of male and female gametes.

Question 2

What is asexual reproduction?

Answer 2

Involves only one parent with no fusion of gametes, only mitosis is involved.

Question 3

What is the process of meiosis?

Answer 3

1. DNA replicates (two copies of genetic information are made)
2. The cell divides twice to form 4 gametes, each with a single set of chromosomes.
3. All gametes are genetically different.

Question 4

What are animal gametes?

Answer 4

Sperm and egg.

Question 5

What are plant gametes?

Answer 5

Pollen and ovum (egg).

Question 6

How is DNA structured?

Answer 6

It is a polymer made up of two strands, forming a double helix.

Question 7

What is a gene?

Answer 7

It is a section of DNA coding for a particular sequence of amino acids to make a specific protein.

Question 8

What does genome mean?

Answer 8

The entire genetic material of an organism.

Question 9

What is an allele?

Answer 9

A different form of the same gene.

Question 10

What is a dominant allele?

Answer 10

Only one copy of this allele is needed in order to be expressed in the phenotype.

Question 11

What does recessive allele mean?

Answer 11

Two copies of this allele must be present in order to be expressed in the phenotype.

Question 12

What does homozygous mean?

Answer 12

Both alleles are the same.

Question 13

What does heterozygous mean?

Answer 13

The alleles are different.

Question 14

What does genotype mean?

Answer 14

The combination of alleles present in the genome.

Question 15

What does phenotype mean?

Answer 15

The characteristics that are physically expressed.

Question 16

What is polydactyly?

Answer 16

A dominant condition resulting in the growth of extra fingers or toes.

Question 17

What is cystic fibrosis?

Answer 17

A disorder of the cell membranes caused by a recessive allele.

Question 18

Why is understanding the human genome important?

Answer 18

1. To search for genes linked to different types of disease.
2. Better understanding and treatment of inherited disorders.
3. Useful in tracing human migration patterns from the past.

Question 19

How is sex determined by chromosomes?

Answer 19

The 23rd pair of chromosomes are XX or XY.

Question 20

Why can characteristics of individuals in a population be different?

Answer 20

The different genes inherited, the conditions in which the organisms have developed, or both.

Question 21

What is the process of natural selection?

Answer 21

A variation in a population caused by a mutation means organisms best adapted to their environment survive and reproduce, passing on their genes and out-competing other organisms.

Question 22

How are new species formed?

Answer 22

If populations are isolated and become so different, they can no longer breed to produce fertile offspring.

Question 23

What are the steps in selective breeding?

Answer 23

1. Choose parents with desired characteristics from a mixed population and breed together.
2. From the offspring, those with desired characteristics are bred together.
3. This continues over many generations until all offspring show desired characteristics.

Question 24

What is a disadvantage of selective breeding?

Answer 24

Organisms can become prone to diseases or have inherited disorders.

Question 25

What is embryo screening?

Answer 25

Test whether embryos have any problems with their chromosomes.

Question 26

Why was Darwin's theory of natural selection not well accepted at first?

Answer 26

Due to a lack of evidence.

Question 27

What was the difference between Charles Darwin and Lamarck's theory of natural selection and evolution?

Answer 27

Lamarck believed that organisms could acquire characteristics during their lifetime that they could pass down to their offspring, but Darwin did not believe these traits could be passed down.

Question 28

What are examples of selective breeding?

Answer 28

Disease resistance in food crops. Animals produce more meat or milk. Domestic dogs with gentle nature. Larger or unusual flowers.

Question 29

What is the theory of evolution?

Answer 29

All species are related and gradually change over time.

Question 30

What is selective breeding?

Answer 30

It is an artificial process in which organisms with desired characteristics are chosen as parents for the next generation.

Question 31

What does genetic engineering involve?

Answer 31

1. Enzymes are used to isolate desired gene. 2. This gene is 'cut out' and inserted into a vector (bacterial plasmid or virus). 3. The vector is used to insert gene into required cells. 4. Desired gene is transferred to animal, plant or microorganisms' cells at early stages of development so they can develop with desired characteristics.

Question 32

How have plants been genetically engineered?

Answer 32

Resistance to insect attacks and increased yields.

Question 33

How can genetic engineering be used in medicine?

Answer 33

Modern medical research is exploring the possibility of genetic modification to overcome some inherited disorders.

Question 34

Why might people be opposed to genetic modification?

Answer 34

Potential effects on wild flowers and insects and eating genetically modified crops may have side effects on human health as it has not been fully explored.

Question 35

What sources of evidence is there for evolution?

Answer 35

Fossil records and antibiotic resistance in bacteria.

Question 36

What is a fossil?

Answer 36

The remains of organisms found in rocks.

Question 37

How may fossils have been formed?

Answer 37

Parts of the organism didn't decay. Parts of the organism were replaced with minerals. Preserved traces of organisms such as footprints.

Question 38

What is the reasoning for lack of early life form fossils?

Answer 38

Early life forms were soft bodied, and early rocks have been destroyed by geological processes.

Question 39

What does extinction mean?

Answer 39

No remaining individuals of a species still alive.

Question 40

What factors contribute to extinction of a species?

Answer 40

New predators, new diseases and changes in environment, new competition.

Question 41

Why do bacteria evolve quickly?

Answer 41

Bacteria reproduce at a fast rate.

Question 42

What are the steps in developing antibiotic resistance?

Answer 42

Bacteria are exposed to antibiotics. Mutations produce new strains of bacteria. Some strains are antibiotially resistant and survive and reproduce.

Question 43

How can development of antibiotic resistance be reduced?

Answer 43

Doctors only prescribing antibiotics for life-threatening conditions. Patients completing full course of antibiotics so all bacteria are killed and none survive to mutate to form resistant strains. Agricultural use of antibiotics should be restricted.

Question 44

Who developed the traditional method of classification?

Answer 44

Carl Linnaeus.

Question 45

What are the levels of classification/organisation?

Answer 45

Domain, Kingdom, Phylum, Class, Order, Family, Genus and Species.

Question 46

What are the two parts to the binomial system?

Answer 46

Genus and species.

Question 47

How has the classifications system improved?

Answer 47

Due to better microscopes and understanding of biochemical processes.

Question 48

What is the three domain system?

Answer 48

Archaea: Prokaryotic cells living in extreme conditions. Bacteria: True bacteria. Eukaryota: Broad range of organisms including plants, animals, fungi and protists.