Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Gcse Biology > Topic 3 - Genetics > Flashcards

Topic 3 - Genetics Flashcards

1
Q

What is sexual reproduction?

A

Type of reproduction

Involves the production of gametes by meiosis

A gamete from each parent fuses to form a zygote

Genetic information from each gamete is mixed so the resulting zygote is unique

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is meiosis?

A

Form of cell division involved in the formation of gametes

Chromosome number is halved

Involves two divisions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What must occur prior to meiosis?

A

Interphase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why is meiosis important for sexual reproduction?

A

It increases genetic variation

It ensures that the resultant zygote is diploid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the advantage of sexual reproduction?

A

It creates genetic variation, increasing the probability of a species adapting to and surviving environmental changes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the disadvantages of sexual reproduction

A

Two parents are required. This makes the reproduction difficult in endangered populations or in species which exhibit solitary lifestyles.

More time and energy is required so fewer offsprings are produced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is produced in meiosis?

A

4 haploid gametes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Asexual reproduction?

A

Involves mitosis

Genetically identical offspring known as daughter cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the advantages of asexual reproduction

A

Only one parents is required

Lots of offspring can be produced in a short period of time, enabling the rapid colonisation of an area and reducing competition from other species

Requires less energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the disadvantage of asexual reproduction?

A

No genetic variation (except from spontaneous mutations) reducing the probability of a species being able to adapt to environmental change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is DNA

A

A double-stranded polymer of nucleotides, wound to form a double helix.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are monomers of DNA?

A

Nucleotides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are DNA nucleotides made up of?

A

Common sugar
Phosphate group
One of four bases: A,T,C or G

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe how nucleotides interact to form a molecules of DNA

A

Sugar and phosphate molecules join to form a phosphate-sugar backbone in each DNA strand

Base connected to each sugar

Complementary base (A pairs T, C pairs with G)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Define genome

A

The entire genetic sequencing of an organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Define gene

A

A section of a DNA molecule that codes for a specific protein.

17
Q

What is a chromosome?

A

A long, coiled molecules of DNA that carries genetic information in the form of genes.

18
Q

Describe the method to used to extract DNA from fruit

A
19
Q

Why is detergent added to crushed fruit?

A

It disrupts the cell membranes, releasing DNA into solution

20
Q

Why is salt added to the crushed fruit?

A

Salt encourages the DNA to clump together

21
Q

Why is chilled ethanol added rather water

A

DNA is insoluble is ethanol, encourage its precipitation

22
Q

Outline how the work of Mendel helped scientists to develop their understanding of genetics?

A

Mendel studied the inheritance of different
phenotypes of pea plants

He establishes a correlation between parent and offsprings phenotypes

He noted that inheritance was determined by “units” passed onto descendants

Using gene crosses, he devised the terms “dominant” and “recessive”

23
Q

Why was Mendel’s work initially overlooked

A

Scientist’s didn’t understand Mendel work as there was no knowledge of genes or DNA at that time.

24
Q

What is a chromosome?

A

A long, coiled molecule of DNA that carries genetic information in the form of genes

25
Q

What are alleles?

A

Different versions of the same gene

26
Q

Define genotype

A

An organism’s genetic composition describes all alleles

27
Q

Define phenotype

A

An organism observable characteristics due to interactions of the genotype and environment (which can modify the phenotype)

28
Q

Define homozygous

A

Having two identical alleles of a gene

FF or ff

29
Q

Define heterozygous

A

Having two different alleles of a gene e,g Ff

30
Q

What is a dominant allele?

A

Describes an allele that is always expressed

Representes with a capital letter e,g F

31
Q

What is a recessive allele?

A

An allele that is only expressed in absence of a dominant alleles
Represented with a small letter e,g f

32
Q

What is monohybrid inheritance?

A

The inheritance of a single gene

33
Q
A
34
Q
A
35
Q

What are sex chromosome?

A

A pair of chromosomes that determine sex :
Males have an X and a Y chromosome
Females have two X chromosomes

36
Q
A
37
Q

Why does the inheritance of a Y chromosome mean that an embryo develops into a male?

A

Testes development in a embryo is stimulated by a gene present on the Y chromosome.

Gcse Biology (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions