Genetics

Question 1

Genome

Answer 1

All the genetic material of an organism

Question 2

Chromosome

Answer 2

Made up of DNA. Sections of a chromosomes are called genes

Question 3

Gene

Answer 3

Section of chromosome that codes for a characteristic

Question 4

Allele

Answer 4

Different forms of the same gene e.g. Gene for eye colour - alleles may be brown, blue, green

Question 5

DNA

Answer 5

Made up of nucelotides - which contain a deoxyribose sugar, phosphate group and a base

Question 6

Bases found in DNA

Answer 6

A (adenine)
T (Thymine)
C (Cytosine)
G (Guanine)

Question 7

Which bases form base pairs with each other

Answer 7

A with T
C with G

Question 8

Name of the shape of a DNA molecule

Answer 8

Double Helix

Question 9

Antiparallel strands

Answer 9

The two strands of DNA run in opposite direction to each other

Question 10

What does DNA code for

Answer 10

A protein

Question 11

What is the triplet code

Answer 11

The order of 3 bases that code for a particular amino acid

Question 12

If a gene is made up of 60 bases on the coding strand, how many amino acids is this protein made up of

Answer 12

3 bases = 1 amino acid
60 bases = 20 amino acids
the protein that this gene codes for is made up of 20 amino acids

Question 13

If a protein is made up of 15 amino acids. What is the minimum number of bases required in the gene that codes for this protein

Answer 13

3 bases = 1 amino acid
This protein has 15 amino acid so
15 x 3 bases = 45 bases required

Question 14

What are the 2 types of cell division

Answer 14

Mitosis and Meiosis

Question 15

Which cell division produces cells that are genetically identical

Answer 15

Mitosis

Question 16

Which cell division produces cells that are genetically different

Answer 16

Meiosis

Question 17

What is mitosis used for

Answer 17

Growth
Replace worn out cells
Repair damaged tissues
Asexual reproduction

Question 18

What is meiosis used for

Answer 18

Producing sex cells - gametes

Question 19

Before cell division occurs what happens to the number of chromosomes

Answer 19

The number doubles - the chromosomes make a copy of themselves before division

Question 20

In mitosis describe what happens

Answer 20

The chromosomes duplicate themselves (e.g. go from 46 chromosomes to 92 chromosomes)
The cell divides in 1 division
Produces 2 diploid daughter cells (each containing 46 chromosomes)
All genetically identical to parent cell and each other

Question 21

Describe what happens during meiosis

Answer 21

The chromosomes duplicate themselves (e.g. go from 46 chromosomes to 92 chromosomes)
The cell divides twice - 2 divisions
Produces 4 haploid daughter cells (each containing 23 chromosomes)
All genetically different

Question 22

As meiosis halves the number of chromosomes in the daughter cells, what is the term used to describe this type of division

Answer 22

Reduction Division

Question 23

During meiosis variation arises due to the different possible chromosome combinations that can be formed. What is this known as

Answer 23

Independent assortment

Question 24

Haploid

Answer 24

Half the chromosome number (23 individual chromsomes in humans)
Found in gametes

Question 25

Diploid

Answer 25

Normal number (23 pairs of chromosomes in humans) Normal cells are diploid

Question 26

Dominant allele

Answer 26

An allele that will code for a characteristic even when only one is present. Represented as capital letter e.g B

Question 27

Recessive allele

Answer 27

An allele that will control development of a characteristic ONLY if both alleles are recessive Represented in lower case e.g bb

Question 28

Heterozygous

Answer 28

Both alleles are different e.g. Bb

Question 29

Homozygous

Answer 29

Both alleles are the same e.g. homozygous dominant BB or homozygous recessive bb

Question 30

Genotype

Answer 30

The genetic make up of individual for a characteristic e.g. Bb

Question 31

Phenotype

Answer 31

The physical feature that the genotype codes for e.g. brown eyes

Question 32

Test cross

Answer 32

To find out if an organism that has the dominant characteristic is homozygous dominant or heterozygous Will cross with a homozygous recessive

Question 33

Describe the outcome of the test cross

Answer 33

If parent homozygous dominant all offspring display dominant characteristic as are all heterozygous If parent is heterozygous then half will have the dominant characteristic and half will display recessive characteristic

Question 34

Sex chromosomes of male

Answer 34

XY

Question 35

Sex chromosomes of female

Answer 35

XX

Question 36

Chance of having a girl

Answer 36

50% - half sperm are X and half are Y All eggs are X

Question 37

Pedigree diagram

Answer 37

A family tree used to show how genetic conditions are inherited in a family

Question 38

Cystic fibrosis

Answer 38

Caused by recessive allele To have condition must be homozygous recessive (cc) if parents are carriers they are heterozygous (Cc) and have 25% chance of having a child with Cystic Fibrosis

Question 39

Huntingtons Disease

Answer 39

Caused by dominant allele (H) Symptoms only display in middle age so may have passed on to offspring Parent could be heterozygous (Hh) or homozygous dominant (HH)

Question 40

Down's Syndrome

Answer 40

Chromosome mutation Have extra chromosome on pair 21 Have 47 chromosomes instead of 46

Question 41

Karyotype

Answer 41

A diagram that lays out all the chromosomes pairs in an individual - used to help identify sex of person and if they have down syndrome

Question 42

Punnett Square

Answer 42

used to conduct a genetic cross

Question 43

Haemophila

Answer 43

Sex linked condition - found on the X chromosome More common in males as they only inherit one X chromosome

Question 44

Genetic screening

Answer 44

Used to identify the presence of genetic condition in an individual

Question 45

Amniocentesis

Answer 45

Used to test for Down Syndrome Involves removal of some amniotic fluid (includes foetal cells) Grow in lab examine chromosomes to identify if individual has down syndrome

Question 46

Concerns with amniocentesis and genetic screening

Answer 46

Amniocentesis has risk of miscarriage Ethical issues - if diagnosed with genetic condition - abortion, right to life, religious beliefs will child need extra medical needs/costs

Question 47

Genetic engineering

Answer 47

Changing the genetic make up of an organism by incoporating DNA from a different organism

Question 48

How is DNA cut out of a human gene

Answer 48

Using restriction enzyme

Question 49

Describe how are bacteria involved in genetic engineering to produce human insulin

Answer 49

Restriction enzyme cuts gene out of human chromosome SAME restriction enzyme cuts open plasmid Gene is inserted into plasmid Genetically modified plasmid placed inside bacteria Bacteria allowed to multiply in a bioreactor/fermenter Bacteria start producing human insulin

Question 50

What happens in Downstream Processing

Answer 50

To obtain a pure sample of insulin from the bioreactor the following 3 steps are involved: Extraction (of insulin mixture from bioreactor) Purification (to remove debris and bacteria from mixture so only insulin present) Packaging (bottle the insulin to distribute to patients)

Question 51

Function of paddle stirrers in bioreactor

Answer 51

To keep the mixture of bacteria and food solution mixing and prevent the bacteria settling at bottom of reactor

Question 52

Why is there a cooling jacket around a bioreactor

Answer 52

To help control the temperature- bacteria respire and release heat energy. If temperature increases too much the enzymes denature and bacteria die. Cooling jacket removes this heat energy

Question 53

What will the computer probes monitor in the bioreactor

Answer 53

pH, Temperature, Oxygen levels, nutrient levels (possible examples)