B6 Genetics

Question 1

Genome

Answer 1

The entire genetic material of that organism

Question 2

Chromosomes

Answer 2

The DNA is found within structures

Question 3

Gene

Answer 3

A short section of DNA that contains the instruction for one characteristics of an organism

Question 4

DNA genes and chromosomes

Answer 4

Human cells have 46 chromosomes
DNA has proteins associated with it that help condense into chromosomes
Mitochondria contain DNA
Plasmids contain DNA but don’t contribute to the running of the cell

Question 5

Gene therapy and genome edititing

Answer 5

Developing effective treatments to target and correct genes

Question 6

Understanding someone’s genome may allow doctors to:

Answer 6

Recommend better preventative medicine
Identify the targets of drugs more effectively
Tailor healthcare to the individual

Question 7

Understanding more about the human genome

Answer 7

In late 20th C it was estimated that there were around 1000000 genes in the human genome
There are much less however 20000-25000 code for proteins this around 1.5% of the human genome
There are no coding areas which control gene expression turning on and off genes

Question 8

The Genographic project

Answer 8

Looks at characterises on the male Y chromosomes and DNA in mitochondria from women

Question 9

What were the findings of the TGP

Answer 9

That people originated from Africa

And that they migrated 60000 years ago through Arabia

Question 10

Structure of DNA

Answer 10

A double helix structure

Like a gently twisted ladder

Question 11

Bases in DNA

Answer 11

Adenine A
Thymine T
Cytosine C
Guanine G

Question 12

DNA is a polymer

Answer 12

Made up of repeating units call nucleotides

Question 13

Genetic code

Answer 13

Is the bases that make up this
Our genome contains approximately 3.3billion base pairs
Genes vary in size from a few hundred bases for more than 2 million

Question 14

Complementary base pairs

Answer 14

A&T

C&G

Question 15

Genes are needed to assemble proteins

Answer 15

Genes provide code for assembly of proteins
All proteins made up of same 20 amino acids
4 base pairs work in triplets for each amino acid

Question 16

Protein synthesis

Answer 16

DNA unzips the bases of a gene act as template for a messenger molecule
Messenger molecule leaves the nucleus containing the code for the amino acid
In the cytoplasm the messenger molecules attaches to a ribosome
The base pairs are complementary. The carrier attaches to the ribosome
A second amino acid is ferried to the ribosome
The second amino acid is able to attach because of the sequence of its bases
A peptide bond is formed between the two anime acids
The messenger molecule is shunted along the ribosome and another amino acid is ferried in

Question 17

The shape of proteins

Answer 17

Proteins bend into unique shapes creating an active site

When a complementary substrate fits into its active site a reaction can occur

Question 18

Mutations

Answer 18

Changes to our DNA

Usually to help a species survive

Question 19

Mutations to amino acids

Answer 19

Some changes may not directly affect the function of an amino acid
If it occurs in a non coding area a gene may be expressed differently

Question 20

Mutations can have serious side effects

Answer 20

A change in bases to code for a protein may result in a different protein being produced
Therefore the active site is different and specific chemical reactions can not occur

Question 21

During meiosis

Answer 21

4 gametes are produced from one parent

Each gamete has half the number of chromosomes of the parent cell

Question 22

What happens during meiosis

Answer 22

There is 2 sets of division

The DNA is copied and then split

Question 23

Genetic variation

Answer 23

Each gamete receives different characteristics

Question 24

What determines our sex

Answer 24

Wether we receive X or Y chromosomes determines wether we are male or female

Question 25

Asexual reproduction

Answer 25

``` Involves only one parent Offspring are clones of parents Good if can't find a partner Produces lots of offspring quickly in favourable conditions Requires less energy ```

Question 26

Sexual reproduction

Answer 26

Genetic material comes from both parent Produces variation If environment changes some offspring are more likely to survive than others through natural selection

Question 27

Using both forms of reproduction

Answer 27

Some species can use either form to reproduce making their survival greater

Question 28

Adapting to circumstances

Answer 28

Sexual reproduction helps increase the chance of survival

Question 29

Cystic fibrosis

Answer 29

Is an inherited disorder Thick sticky mucus makes it hard to breathe Linked to chromosome 7 Occurs when alleles of CFTR are defective

Question 30

Dominant or recessive

Answer 30

Dominant only need one allele of it | Recessive needs two alleles for it to be inherited

Question 31

Genotype

Answer 31

Alleles present for a particular gene

Question 32

Phenotype

Answer 32

How the gene is expressed | Physical appearance of characteristics eg eye colour

Question 33

Homozygous

Answer 33

Having 2 of the same allele either recessive or dominant

Question 34

Heterozygous

Answer 34

2 different alleles both recessive and dominant

Question 35

Punnet square

Answer 35

Shows all the possible outcomes of the children based on the parents alleles

Question 36

Gene disorders

Answer 36

Generally caused by recessive alleles | Although some can be dominant

Question 37

Family tree diagrams

Answer 37

Allows us to see how the condition is passed down in the family

Question 38

Embryo screening

Answer 38

Embryos can be screened for genetic disorders | If one if found it is up to the parents to decide whether to keep it or not

Question 39

Gregor Mendel

Answer 39

Was a Monk at a monastery in Bünn now Brno in the Czech Republic

Question 40

Why did Mendel choose peas

Answer 40

``` A wide variety available Each trait was sharply defined Fertilisation can be controlled Easy to cultivate They grow and flower He started with pure lines for 2 years ```

Question 41

Mendels hypothesis

Answer 41

Inheritance of each characteristic was in units which were passed to descendants Each plant has a pair of factors governing a particular characteristic One of these factors at random would go into a gamete

Question 42

How did he test his hypothesis

Answer 42

Used colour seed trait test Cross bred 2 colours Predicted 1:1 ratio But ended up with 58 yellow and 52 green

Question 43

Reproducibility of Mendels experiment

Answer 43

Very reproducible as many other scientists have done it and received similar results