Genetics

Question 1

What are the 2 types of reproduction?

Answer 1

Asexual and sexual reproduction

Question 2

What are the 3 steps of sexual reproduction?

Answer 2

• Mother gamete fuses with father gamete
• Mix genetic info
• Offspring have different combinations of genes from each parent to show a variety of characteristics

Question 3

What are the advantages and disadvantages of sexual reproduction?

Answer 3

-Offspring are genetically different to parent and each other, so there is the variation; if the environment changes, then some individuals may survive
BUT
-The organism has to find a mate to reproduce which takes time and energy

Question 4

What are the 3 aspects of asexual reproduction?

Answer 4

• No fusion of gametes; only one parent
• No mixing of genetic info
• All offspring have identical genes to the parent and each other

Question 5

What are the advantages and disadvantages of asexual reproduction?

Answer 5

-Only one parent; no need to find a mate so is faster
BUT
-All offspring are genetically identical so no variation in population; if the environment changes, all may die

Question 6

What does asexual reproduction produce?

Answer 6

Clones - identical to the parent

Question 7

What is meiosis?

Answer 7

A type of cell division that produces 4 daughter cells each with half the amount of chromosomes (haploid number)

Question 8

What is a gene?

Answer 8

A section of DNA that codes for a particular protein

Question 9

Describe the stages of meiosis

Answer 9

• Parent cell is diploid
• DNA replication (chromosomes copy themselves and stay attached to each other)
• Cell splits in 2 with each new cell haploid
• Divides in 2 again
• Four daughter cells now haploid
• Mix of genetic info

Question 10

What is an acronym to help remember the stages of meiosis?

Answer 10

President
Donald
Cannot
Do
For
Me

Question 11

What is the genome?

Answer 11

All the DNA of an organism

Question 12

What are the 4 bases in DNA and what do their pair with?

Answer 12

Adenine with Thymine
Guanine with Cytosine
(They are complementary base pairs)

Question 13

What is the grouping of a base pair attached to a sugar which is attached to a phosphate group called?

Answer 13

A nucleotide

Question 14

How many hydrogen bonds form between each base pairs?

Answer 14

C and G = 3

A and T = 2

Question 15

Why is DNA a polymer?

Answer 15

Because it is made up of several monomers called nucleotides

Question 16

Describe how DNA is extracted from fruit

Answer 16

• Grind the fruit with sand using a pestle and mortar to separate the cells
• Add detergent to break open the membranes
• Add ice-cold alcohol so that the DNA precipitates out

Question 17

Why is it important to add detergent to the fruit when breaking open the membranes?

Answer 17

The DNA in the fruit is found in the nucleus which, like the cell, is surrounded by membranes, so to extract the DNA you must break open the membranes by adding detergent

Question 18

What is a mutation?

Answer 18

Where genetic code has not been transcripted properly

Question 19

What is the difference between a DNA and a RNA nucleotide?

Answer 19

DNA has deoxyribose sugar whereas RNA has ribose sugar

Question 20

What is a phenotype?

Answer 20

Observable characteristics - what an organism looks like

Question 21

What are alleles?

Answer 21

Different forms of a gene

Question 22

What are the 3 laws that Mendel created for inheritance?

Answer 22

• Each gamete receives only 1 version for a characteristic
• The version of a characteristic that a gamete receives is random
• Some versions of a factor are more powerful than others and always have an effect on the offspring

Question 23

What does homozygous mean?

Answer 23

The state of having 2 of the same alleles of a particular gene

Question 24

What is meant by heterozygous?

Answer 24

The state of having 2 different alleles of a particular gene

Question 25

What is a dominant allele?

Answer 25

The allele that will always have an effect on an organism

Question 26

What is a recessive allele?

Answer 26

The allele that will only have an effect on an organism’s phenotype when 2 are present

Question 27

What is the genotype?

Answer 27

The alleles in an organism

Question 28

What is the likelihood of an event happening, used in genetic diagrams like Punnett squares?

Answer 28

Probability

Question 29

What is the 3:1 ratio called?

Answer 29

The monohybrid ratio

Question 30

What is codominance?

Answer 30

When both alleles for a gene affect the phenotype

Question 31

What are sex-linked genetic disorders?

Answer 31

Disorders that show a different pattern of inheritance in men and women

Question 32

Why might a person with CF lose body mass?

Answer 32

They produce a lot of mucus that block all the ducts that carry enzymes to the digestive system, meaning less of their food is digested and so there is a less absorption of food; the enzymes work less effectively because of this

Question 33

What is genetic variation caused by?

Answer 33

The different alleles inherited during sexual reproduction

Question 34

What are acquired characteristics?

Answer 34

Characteristics that are changed by the environment during the life of the individual

Question 35

What is discontinuous variation?

Answer 35

Where the data can only take a limited set of values

Question 36

What is continuous variation?

Answer 36

Where the data can be any value in a range