Year 9 Genetics And Inheritance

Question 1

What is DNA?

Answer 1

DNA is the molecule in the nucleus that carries our genetic code.

Question 2

How many chromosomes do normal body cells have?

Answer 2

Normal body cells (e.g. Skin Cell) have 46 chromosomes (23 pairs).

Question 3

What is Deoxyribonucleic acid?

Answer 3

Deoxyribonucleic acid is DNA.

Question 4

What is an allele?

Answer 4

An allele is a different form of a gene. For e.g. let’s say gene is height.

Question 5

How many chromosomes do a Human sex cell have?

Answer 5

A human sex cell (sperm and egg) have half the amount of a normal body cell (23).

Question 6

What is along the length of each chromosome?

Answer 6

Along the length of each chromosome there are coding regions called genes.

Question 7

What do genes have to do with eye colour or height?

Answer 7

Genes code for proteins, which give us our characteristics e.g. eye colour.

Question 8

How is DNA arranged?

Answer 8

DNA is arranged into long, coiled molecules called chromosome.

Question 9

What are alleles for height?

Answer 9

The alleles for height are:

T= Tall (dominant)
t= Small (recessive)

Question 10

What could a person have in the form of alleles?

Answer 10

An individual could have the genotype: TT, Tt or tt

Question 11

What is a gene?

Answer 11

A gene is a section of a chromosome that codes for a particular characteristic.

Question 12

What does parent phenotype mean?

Answer 12

Parent phenotype means what do the parents physically look like. For example the mum has blue eyes and the dad has brown eyes.

Question 13

Which allele is recessive, B black fur or b white fur?

Answer 13

b White fur is the recessive allele.

Question 14

What does it mean by offspring phenotype?

Answer 14

Offspring phenotype is what the parents children physically look like.

Question 15

What does offspring genotype mean?

Answer 15

Offspring genotype is what the parents’ children’s genes are.

Question 16

What are the steps in selective breeding?

Answer 16

1. Decide which characteristics are important (desired characteristics e.g. blue flowers
2. Choose parents that show these characteristics and then breed them together.
3. Select the best offspring from parents to breed the next generation.
4. Repeat the process more and more over a number of years/generations.

Question 17

What is genetic engineering?

Answer 17

Genetic engineering is a process which involves changing the genes of an organism by introducing a gene from another organism to give a desired characteristic.

Question 18

What is an organism whose genes have been altered called?

Answer 18

An organism whose genes have been altered is called a genetically modified organism

Question 19

What is the steps to genetic engineering?

Answer 19

S for Select the desired characteristic
I for Isolate the gene responsible for the characteristic (using enzymes)
I for Insert the gene into another organism (e.g. bacterium)
R for Replication of the organism

Question 20

What are some advantages of Genetic Inheritance?

Answer 20

It can improve crop yield

It can improve resistance to pesticides.

Question 21

What is the meaning of the term accuracy?

Answer 21

A measurement result is considered accurate if it is judged to be close to the true value.

Question 22

What is the meaning of the term precision?

Answer 22

Precise measurements are ones in which there is very little spread about the mean value. Precision depends only on the extent of random errors - it gives no indication of how close results are to the true value.

Question 23

What does the term Repeatable mean?

Answer 23

A measurement is repeatable if the original experimenter repeats the investigation using the same method and equipment and obtains the same results. Previously known as reliable.

Question 24

What is the meaning of the term reproducible?

Answer 24

A measurement is reproducible if the investigation is repeated by another person, or by using different equipment or techniques, and the same results are obtained. Previously known as reliable.

Question 25

What is the meaning of the term True Value?

Answer 25

This is the value that would be obtained in an ideal measurement.

Question 26

What is the meaning of the term validity?

Answer 26

Sustainability of the investigative procedure to answer the question being asked. For example, an investigation to find out if the rate of a chemical reaction dependent upon the concentration of one of the reactants would not be a valid procedure if the temperature of the reactants was not controlled

Question 27

What is the meaning of the term Valid Conclusion?

Answer 27

A conclusion supported by valid data, obtained from an appropriate experimental design based on sound reasoning.