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Biology Unit 1 > Topic 2 - Genes And Health > Flashcards

Topic 2 - Genes And Health Flashcards

(51 cards)

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1
Q

What are the two types of nitrogen- containing bases?

A

Purine - two rings. A and G

Pyrimidines - one nitrogen-containing ring. C, T and U

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2
Q

What is the phosphate group made of?

A

(PO4)^3-

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3
Q

What holds together the two strands in DNA?

A

Hydrogen bonds between complementary base pairs

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4
Q

What is the process of DNA replication?

A

DNA helicase splits strands
Free nucleotides form hydrogen bonds
DNA polymerase and DNA ligase join nucleotides together

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5
Q

What is the type of replication involved in DNA replication?

A

Semi conservative

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6
Q

How was it discovered that the method of DNA replication is semi conservative?

A

Grew e. Coli in medium with only 15N
Transferred to medium with only normal 14N
All DNA same density so semiconservative

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7
Q

What are nucleotides made of?

A

Phosphate
Pentose sugar
Organic nitrogenous base

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8
Q

Where does transcription occur?

A

In the nucleus

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9
Q

Where does translation occur?

A

On the surface of ribosomes

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10
Q

Which strand of DNA acts as a template for mRNA?

A

The antisense strand

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11
Q

What is the method of translation?

A 
mRNA engulfed by ribosome
tRNA attaches to specific amino acids
tRNA molecule lines up against matching mRNA on ribosome
Peptide links formed between amino acids
tRNAs unbind to pick up more amino acids
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12
Q

What is a mutation?

A

A change in the genetic code

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13
Q

What are point mutations?

A

One or a small number of nucleotides miscopied

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14
Q

What are chromosomal mutations?

A

Changes in gene position within the chromosomes

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15
Q

What are gene deletion mutations?

A

Where a gene or set of genes are not copied

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16
Q

What is duplication mutation?

A

Where a gene or set of genes are copied multiple times

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17
Q

What are inversion mutations?

A

Where genes switch positions

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18
Q

What is s translocation mutation?

A

Where genes are copied onto the wrong chromosome

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19
Q

What are whole-chromosome mutations?

A

Where an entire chromosome is lost during meiosis or duplicated in one cell by errors in the process

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20
Q

What are anabolic reactions?

A

Reactions that build up new chemicals

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21
Q

What are catabolic reactions?

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A

Reactions that break substances down

22
Q

What is enzyme specificity?

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A

Only catalyse specific reactions

23
Q

What names do enzymes have?

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A

Recommended name - urease
Systematic name
Classification number

24
Q

What is the induced-fit hypothesis?

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A

Active site not fully complementary to substrate until substrate fits into it

25
What is an enzymes molecular activity (turnover number)?
The number of substrate molecules transformed per minute by a single enzyme molecule
26
What is the temperature coefficient of an enzyme?
Rate of reaction at x+10C / rate of reaction at xC
27
What is a genes locus?
Its position on a chromosome
28
What is polygenic?
Controlled by several interacting genes
29
What is Thalassaemia?
``` Genetic disorder Affect haemoglobin polypeptide chains Prevents formation of either a or B chains in haemoglobin Symptoms of anaemia No cure Treated by blood infusion ```
30
What is alpha Thalassaemia?
Polygenic inheritance Commonly caused by gene deletion Various severities Milder increases malaria resistance
31
What is beta Thalassaemia?
Mutations on one gene Various severities Most severe: Cooley's anaemia Recessive allele
32
What is albinism?
Melanin pigment does not form Polygenic mutations E.g. Tyrosinase not formed so no melanin produced Recessive allele
33
What are multifactorial diseases?
Cause by combination of genes and lifestyle
34
What is the cell membrane structure?
``` Phospholipid bilayer (fatty acid tails away from solution Membrane proteins ``` Fluid mosaic model
35
What is facilitated diffusion?
Diffusion across a membrane through a protein
36
What is an isotonic solution?
Same osmotic concentration inside and outside
37
What is a hypotonic solution?
Osmotic concentration of solution lower than that of the cells
38
What is Fick's law?
Rate of diffusion | = (surface area * concentration)/exchange membrane thickness
39
What is the structure of an alveoli?
Folded sac - high surface area Lung surfactant - prevents collapse Thin walls Steep concentration gradient
40
What is the method of keeping mucus runny?
Chloride ions pumped into epithelial cells from surrounding tissue fluid Chloride ions diffuse into fluid in airways through chloride channels(CFTR channels) CFTR channel proteins prevent sodium ion exit from airways Water moves out of cells and mixes with mucus
41
What does cystic fibrosis cause?
The CFTR channel to not work | Thick, sticky mucus
42
What are symptoms of cystic fibrosis?
Severe coughing fits - mucus build-up in lungs Breathless Pathogen build-up in lungs Prevents digestive enzyme movement to gut - improper digestion and stay in pancreas (damage to pancreas) More difficult for digested food to be absorbed into blood Blocked cervix/tube carrying sperm out Salty sweat
43
What are treatments of cystic fibrosis?
``` Physiotherapy Balanced diet Enzymes taken with food Drug therapies Transplant Infertility treatments Gene therapy ```
44
How does gene therapy work?
Restriction endonuclease cuts out gene and cuts plasmid DNA ligase joins plasmid and gene Recombinant DNA produced Vector inserted
45
What are problems with gene therapy?
Extracellular barriers Intercellular barriers Keeping the gene expression going
46
What are methods of genetic screening?
Amniocentesis Chorionic villus sampling Preimplantation genetic diagnosis
47
How does amniocentesis work?
16th week of pregnancy Amniotic fluid removed Cells cultured
48
What are the disadvantages of amniocentesis?
Late in pregnancy 2-3 weeks before results 1% risk of spontaneous abortion
49
How does chorionic villus sampling work?
8-10 weeks of pregnancy | Embryonic tissue taken
50
What are the disadvantages of chorionic villus sampling?
2.5-4.8% risk of spontaneous abortion | Can't detect problems in paternal X chromosomes
51
How does preimplantation genetic diagnosis work?
Egg and cell fertilised outside body Secondary oocyte removed from each embryo Genetic makeup checked and best implanted

Biology Unit 1 (3 decks)

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