B13

Question 1

Sexual reproduction is

Answer 1

Where genetic info from two organisms is combined to produce offspring which are genetically different to either parent

Question 2

A gamete is

Answer 2

A sperm or egg or pollen

Question 3

In humans, each gamete contains

Answer 3

23 chromosomes

Question 4

The egg and the sperm cell fuse together to form

Answer 4

A cell with the full number of chromosomes (46)

Question 5

Definition or SEXUAL REPRODUCTION

Answer 5

SEXUAL REPRODUCTIONS involves the fusion of make and female GAMETES. because there are TWO parents, the offspring contain a MIXTURE OF THEIR PARENT’S genes

Question 6

Fertilisation

Answer 6

SPERM AND EGG guves OFFSPRING (fertilised egg)

Question 7

Why dies the offspring inherit features from both parents

Answer 7

Uts recieved a mixture of chromosomes from its mum and dad

Question 8

The mixture of genetic material produces

Answer 8

Variations in offsprings

Question 9

ASEXUAL REPRODUCTION DEFINTION:

Answer 9

In ASEXUAL REPRODUCTION there’s only ONE parent. there’s NO FUSION of gametes, NO MIXING of chromosomes and NO GENETIC VARIATION between parent/offspring. Offspring is GENETICALLY INDENTICAL to the parent

Question 10

Advantages of SEXUAL REPRODUCTION?:

Answer 10

-produces variation in the offspring

-if the environment changes variation gives a survival advantage by natural selection

-natural selection can be speeded up by humans in selective breeding to increase food production.

Question 11

Advantages of asexual reproduction

Answer 11

-only one parent needed

-more time and energy efficient as do not need to find a mate

-faster than sexual reproduction

-many identical offspring can be produced when conditions are favourable

Question 12

DNA is a

Answer 12

polymer that is made up of four different nucleotides. Two strands twist together to form a double helix.

Question 13

Each nucleotide is made of

Answer 13

a sugar and phosphate group with one of four different bases attached.

Question 14

The four bases are

Answer 14

A, C, G and T

Question 15

Complementary base pairing is

Answer 15

A always pairs up with T and C always pairs up with G
- the order of bases in a gene that decides the order of amino acids in a protein

Question 16

Whats a template

Answer 16

Template is Made of the part of the DNa that codes for a specific protein. Each protein will have a different template

Question 17

Explain insertions

Answer 17

Insertions are where a new base is inserted into the DNA where it shouldn’t be.

Insertions changes the way the three groups of bases are read, changes the amino acids they code for.

This can cause a knock on affect for the bases further down the line as they cancchange more than one amino acid

Question 18

Deletions explained

Answer 18

Its when a random base is deleted from the DNa base sequence.

They change theway that the base sequence is read and have knock on effects further down sequence

Question 19

Substitutions explained

Answer 19

When a random base in the DNA base sequence is changed to a different base

Question 20

Dominant alleles

Answer 20

Are always expressed even uf only one of the allekes is dominant

Question 21

Recessive alleles

Answer 21

Are only expressed if there are 2 recessive alleles

Question 22

There are — chromosomes in the human body

Answer 22

23 pairs (46)

Question 23

Of these 23 pairs ____ are matched paris of chromosomes that just control characteristics. The ____ pair are labelled ___ or _____. They decide your sex

Answer 23

22, 23rd, XY or XX

Question 24

Homozygote

Answer 24

An individual with two identical alleles for a characteristic (BB or bb)

Question 25

Heterozygote

Answer 25

An individual with different alleles for a characteristic

Question 26

Why do sex cells have half the usual number of chromosomes

Answer 26

Cause each egg and sperm have 23 chromosomes

Question 27

Allele

Answer 27

Different form of a gene

Question 28

Genotype

Answer 28

Describes the alleles present or genetic makeup of an individual regarding a particular characterisitic (Bb or bb)

Question 29

Phenotype

Answer 29

Describes the physical appearance of an individual regarding a particular charscreristics, (black fur or brown fur)

Question 30

Gametes

Answer 30

Egg or sperm cell

Question 31

Carrier

Answer 31

Someone who carries the faulty gene but its recessive (heterozygous)

Question 32

During in vitro fertilisation (IVF), embryos are fertilised in a laboratory, then implanted into the mother’s womb, before it’s implanted, it’s possible to remove a cell from each embryo and analyse its genes. This way….

Answer 32

Many genetic disorders can be detected in this way, such as cystic fibrosis. Also possibke to get DNA from an embryo in the womb and test that for disorders.

Question 33

For embryos produced by IVF - after screening..

Answer 33

Embryos with ‘bad’ alleles would be destroyed

Question 34

For embryos in the womb - screening could lead

Answer 34

to the decision to terminate the pregnancy

Question 35

Against Embryonic Screening

Answer 35

• it implies that people with genetic problems are not wanted - leads to prejudice.
• may come a point where everyone wants screening so they can pick a desirable one
• expensive

Question 36

For Embryonic Screening

Answer 36

• will help to stop people suffering
• treating disorders costs gov MONEY
• there are LAWS to stop it going too far.
• atm parents cannot even select the sex of their baby.

Question 37

IVF explained

Answer 37

• involves collecting eggs from the woman’s ovaries and fertilising them in a lab using the man’s sperm
• involves intra-cytoplasmic sperm injection (ICSI), sperm injected directly into egg.
• fertilised eggs are grown into embryos in a lab incubator.
• once embryos are tiny balls of cells, one or two of them are transferred to the woman’s uterus to improve the chance of pregnancy
• FSH/LH guven before egg collection to stimulate several eggs to mature

Question 38

Fertility treatment pros/cons

Answer 38

Pros:
- gives an infertile couple a child - a pretty obvious benefit
CONS:
- multiple births can happen (high rist of stillbirth…)
- success rate low - process stressful (physically/mentally)
-

Question 39

Against IVF

Answer 39

Results in unused embryos that are enventually destroyed.
- some people think its unethical - potential human life each embryo
- genetic testing of embyos implantation also raises ethicak issues as some people think it coukd lwas to the selection of preferred characterisitcs.