DNA And The Book Of Life

Question 1

What did Gregor Mendel do

Answer 1

Formulated laws of heredity in 1860s
Austrian monk
Crossed plants and described offspring

Question 2

What experiment did Mendel do

Answer 2

Crossed tall and short pea plants
Tall gene is dominant over short

Question 3

What did Thoman Hunt Morgan claim

Answer 3

Genes lay on chromosomes
Worked with flies eye colour
Eye colour followed similar patterns to pea plant inheritence

Question 4

Order of how things were discovered in molecular biology

Answer 4

1940 - relationship between genes and proteins
44 - genes made of DNA Oswald Avery
52 - DNa responsible for heredity in viruses
53 - watson and crick dna model
60 - proteins bind onto DNA that express genes
61 - mRNA discovered
61-65 - relationship of DNA to RNA to protein discovered link in DNA and protein sequence

Question 5

What is. Gene

Answer 5

Hereditary unit of a living cell
Genetic code that codes for a mRNA

Question 6

What is the central dogma

Answer 6

How info can pass from DNA sequences through RNA sequences to end up as protein sequences

Question 7

What do structural proteins produce

Answer 7

Collagen
Elastin

Question 8

What do signalling proteins produce

Answer 8

Insulin
Neurotransmitters

Question 9

What di enzyme proteins produce

Answer 9

Amylase
Trypsin

Question 10

What do transcription factors produce

Answer 10

Pancreatic duodenal homeobox protein
Signal transfucers and activators of transcription protein

Question 11

How did archibald garrold know genes make proteins

Answer 11

Isolated a substance from joints of affected children
Enzymes responsible for build up of this substance (homogetistic acid)

Question 12

What did garrod found out

Answer 12

Type of mould could have its DNA mutated by xray radiation
Many strains couldn’t grow unless extra nutrients were added
Many genes effect metbolism of specific amino acids required fro mould to grow

Question 13

Gene expression regulation process

Answer 13

1) Rmodeling of chromatin (wrap tight or lose around histones)
2) Transcriptional control = whether genes switches on or off
3) Processing control
4) Transport control through nuclear pore
OR MRNA stability control
5) Translational control of protein synthesis
OR produces inactive mRNA
6) Protein degradation or Posttranslational control of protein activity

Question 14

Positive and negative regulators

Answer 14

Positive = enhancers
Negtive = repressors
Combination of factors determines rate of transription

Question 15

W2hat are the 3 criteria for DNA recoggnition by protein motif

Answer 15

Fits into major or minor groove
Has amino acids that can project into interior of double helix
Has amino acids that can bond with interior bases

Question 16

How are genes switched on

Answer 16

Signalling molecules outside the cell bind to receptors that trigger cascades in the cell
OR
Nuclear receptors act as a receptor or DNA binding protein

Question 17

WHat are mutations

Answer 17

Changes in nucleotide sequences of DNA that are passed on to the next generation

Question 18

Two general types of mutation

Answer 18

Somatic mutations = somatic cells passed on by mitosis but not to sexually produced offspring
Germ line mutations = germ line cells that give rise to gametes, gamete passes on mutation in fertilisation

Question 19

Whats a point mutation

Answer 19

Gain, loss or substitution of single nucleotide

Question 20

Chromosomal mutations

Answer 20

Change position or cause DNA segment to be duplicated or lsot

Question 21

What is phenylketouria disease

Answer 21

Phenylpyruvic acid builds up in urine
Mental retardation occurs
Dysfunctional enzyme which affected a single protein which caused the disease

Question 22

How is a genetic disease caused

Answer 22

Mutant gene produces non functioning enzyme
Build up of substrate produced which causes disease

Question 23

Treating genetic diseases

Answer 23

-Restrict substrate = Less substrate = less symptoms
-Add metabolic inhibitor = blocks harmful effects of built up substrae
-Restore missing enzyme = addition of wild type protein substitutes for the mutant enzyme

Question 24

How are genetic diseases treated

Answer 24

Gene therapy = supply misisng genes by inserting a new gene that will be switched on in host cells

Question 25

Challenges of gene therapy

Answer 25

Find appropriate vector Ensure precise insertion into host DNA Ensure appropriate expression Select cells to target

Question 26

What do ex vivo techniques do

Answer 26

Cell are removed from body New genes inserted in lab Cells returned to body so correct gene products are made

Question 27

How does SCID use gene therapy (ex vivo)

Answer 27

IL2RG gene inserted into genome of SCID sufferer Worked in many cases but leukaemia as consequence of treatment Boy lived in bubble and died at 13 from viral infection from bone marrow transplant

Question 28

What does in vivo gene therapt do

Answer 28

Gene inserted directly into body cells Hope DNA will be incorporated into patients genome and disease will improve or disappear

Question 29

Hierarchical sequencing

Answer 29

Overlap parts of sequences are aligned to create larger sequences Larger fragments arranged in sequence produce chromosome map

Question 30

Shotgun sequencing

Answer 30

Cuts DNA into smaller overlapping fragments that are sequences Computers search for overlapping markers Approach is faster and cheaper

Question 31

What does pharmacogenomics do

Answer 31

Makes it possible to predict whether a drug will be effective Aim is to personalise drug treatments

Question 32

Nuclear transfer experiments process

Answer 32

Nucleus removed from unfertlised egg forming enucleated egg Nucleud of embryo injected into enucleated egg Eggs divide and develop into a clone from the original implanted nucleus Cytoplasmic environment can modify cells fate

Question 33

How does Pharming crops improve nutritional characteristics

Answer 33

Rice does not have beta carotene but has precursor molecule Genes for enzymes that synthesize beta carotene from the precursor are taken from daffodils and inserted into rice

Question 34

Pluripotent

Answer 34

Blastocyst embryonic stage Retain the ability to form all of the cells in the body Embryonic stem cells canbe removed from the blastocyst and grown in lab culture