Heredity

Question 1

Sexual Reproduction

Answer 1

Reproduction involving two parents, who produce offspring that contain a mix of the parent’s genes and therefore differ from each other and from the parents.

Question 2

Asexual Reproduction

Answer 2

reproduction involving only one parent and no sex cells or gametes, resulting in offspring that are genetically identical to each other and to the parent.

Question 3

Disadvantages of Sexual Reproduction

Answer 3

Time and energy

Question 4

Advantages of sexual reproduction

Answer 4

genetic diversity

Question 5

Advantages of asexual reproduction

Answer 5

Efficient

Population is able to increase in size very quickly

Question 6

Disadvantages of asexual reproduction

Answer 6

low genetic diversity - higher vulnerability to change

Question 7

Germination (plants)

Answer 7

seed lands in suitable soil that provides sufficient water, oxygen, and warmth, the embryo begins to grow,

Question 8

Budding (asexual in organisms)

Answer 8

An adult organism gives rise to a small bud, which separates from the parent and grows into a new individual.

Question 9

Binary fission (asexual)

Answer 9

A newly divided cell grows to twice its size, replicates its genetic material and then splits into two cells with identical genetic material

Question 10

Spores (asexual)

Answer 10

unicellular reproductive cells that are produced in great numbers by organisms such as fungi and some plants

Question 11

Fertilisation (sexual)

Answer 11

Sperm are attracted to the egg by rheotaxis for internal fertilisation.

Question 12

External fertilisation - advantages

Answer 12

Can have lots at once
can keep reproducing without pausing
Can give more variation as there's millions of gametes
Suited for an aquatic environment
Less time and energy from parent

Question 13

External fertilisation - disadvantages

Answer 13

Chances of gametes meeting are less because they could be in different areas (current moving things in wrong direction).
Exposed to predation, infection - less likely offspring to survive.
No parental care

Question 14

Internal Fertilisation - advantages

Answer 14

Increased likelihood of fertilisation because they are being fertilised in a small space (Vagina).
Baby is inside the stomach - will be free from external disease such as covid-19 leading to higher survival rate.
Fewer eggs need - important for conserving energy

Question 15

internal Fertilisation - disadvantages

Answer 15

produce less offspring = less likely chance of species surviving.
Less variation compared to external

Question 16

Hormones involved in mammalian reproduction

3

Answer 16

1. Androgens- male hormones, control development and functioning of male sex organs and secondary sex characteristics.
2. Oestrogens- main group of female hormones. Control the development and functioning of the female reproductive system and secondary sex characteristics.
3. Progestogens- a second group of female hormones. Progesterone is the most common progestogen and it plays a primary role in pregnancy.

Question 17

Hormonal control of the female reproductive cycle

3 steps

Answer 17

Endocrine glands regulate and control the ovarian and menstrual cycles, coordinating them to ensure fertility → increase in probability of successful reproduction → continuity of species.

Question 18

Hormonal Control of the male reproductive cycle

1 step, 3 glands

Answer 18

Spermatogenesis is controlled by hormones → involves interaction of three glands: hypothalamus in the brain, pituitary gland at the base of the brain and Leydig cells in testes.

Question 19

Mitosis

Answer 19

cell division resulting in two identical daughter cells, with the same number and kind of chromosomes as the parent cell

Question 20

Meiosis

Answer 20

cell division resulting in four daughter cells (gametes), each with half the number of chromosomes of the parent cell

Question 21

The role and importance of mitosis

Answer 21

Growth of multicellular organisms
Repair of damaged tissue and replacement of worn-out cells
Asexual reproduction
Genetic stability

Question 22

The role and importance of meiosis

Answer 22

ensure that each parent contributes only half of his or her chromosomes to the new offspring
ensures that the chromosomes number of each species is maintained (not doubled) during sexual reproduction

Question 23

why does DNA need to replicate exactly?

Answer 23

allows it to function properly, to its physical features and body size.
so that each resulting daughter cell ends up with its own complete genome.

Question 24

three ways prokaryotic and eukaryotic DNA are SIMILAR:

Answer 24

Prokaryotes and eukaryotes package their DNA molecules with protein in structures called chromosomes

Prokaryotic DNA gene sequences can code for multiple proteins, as well as some Eukaryotic DNA

DNA is double-stranded in both Prokaryotic and Eukaryotic DNA

Question 25

transcription - Process of polypeptide synthesis

Answer 25

genetic information is transferred from a double helical DNA to a single stranded mRNA.
(scripting the bonds to the ribosomes)

Question 26

translation Process of polypeptide synthesis

Answer 26

“decoding” a messenger RNA (mRNA) and using its information to build a polypeptide, or chain of amino acids.

Question 27

Messenger RNA (mRNA)

Answer 27

Serves as an intermediate molecule, carrying information from DNA in the nucleus to ribosomes in the cytoplasm

Question 28

Transfer RNA (tRNA)

Answer 28

Specific sequence of three bases at anticodon end determines which amino acid will be made

Question 29

Ribosomal RNA (rRNA)

Answer 29

Forms structural part of ribosomes

Question 30

importance of polypeptide synthesis

Answer 30

the building blocks of proteins, which are essential to cell function

Question 31

Gene expression and phenotype

Answer 31

the expression of genes in an observable way, is an obvious and measurable trait.

Question 32

Chemical structure of protiens

Answer 32

Proteins contain chemical elements carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. These elements combine to form amino acids, which are the building blocks of proteins.

Question 33

Physical structure of protiens

primary, secondary, tertiary, and quaternary.

Answer 33

primary - chain of amino acids
secondary - amino acids fold into repeating pattern
tertiary - 3-dimensional folding of pattern
quaternary - protein consisting of more then 1 amino acid chain

Question 34

Autosomal - Inheritance Pattern

Answer 34

One trait is dominant & one trait is recessive

Question 35

Sex-linked (X)- inheritance

Answer 35

Trait only carried on X & not the Y chromosome

Question 36

Codominance - inheritance

Answer 36

Both traits are expressed at the same time.

Question 37

Incomplete dom - inheritance

Answer 37

Traits are blended when they receive two alleles

Question 38

Multiple Alleles - inheritance

Answer 38

More than 2 alleles are involved.