Biology Molecular Genetics

Front 1

How is DNA organised inside a nucleus?

1. DNA consists of (3 points)

2. How does it form a chromatin thread

3. During Cell Division (2)

Back 1

Each DNA consists of:

1. 2 parallel strands

2. twisted around each other

3. to form a double helix

Molecule of DNA is wrapped around proteins to form a single chromatin thread

During Cell division:

1. chromatin threads coil more tightly

2. form chromosomes

Front 2

What is DNA?

Back 2

Deoxyribonucleic Acid

A molecule that contains genetic information.

Made of Nucleotides:

(joined to form polynucleotides)

- 1 Deoxyribose Molecule (sugar)

- 1 Phosphate Group

- 1 Nitrogen Containing Base

(Adenine, Guanine, Cytosine, Thymine)

Front 3

DNA Structure

Back 3

1. 2 anti parallel polynucleotide strands that coil to forma double helix

2. Where Bases on one strand forms bonds on the other acc. to rule of base pairing

Front 4

Name the pairs of complementary bases (2)

Back 4

Purine:

Adenine & Thymine (AT)

T replaced with U (Uracil) during transcription

Pyrimidine:

Guanine & Cytosine (GC)

Front 5

Define Gene (5)

Back 5

1. A unit of inheritance.

2. A small segment of DNA made of a

3. Specific sequence of nucleotides.

4. Each gene codes a particular polypeptide that

5. determines a particular characteristic in organisms.

Front 6

Define Codon

Back 6

Three nucleotides

- each codes for 1 amino acid

Front 7

What is the Genetic Code

Back 7

States which amino acid each codon codes for

Front 8

What happens when the nucleotide sequence is altered? (2)

Back 8

Gene Mutation

EG. Albinism & Sickle Cell Anaemia

1. May or may not lead to a changed protein product

2. Changed 1) May or may not lead to observable phenotype

Front 9

2 Examples of Gene Mutation

Back 9

1. Albinism

Absence or defect in enzyme that produces pigment

2. Sickle-cell Anaemia

Protein product differ from normal protein by 1 amino acid, causing red blood cells to be sickle shaped

Front 10

How are proteins made? (2 process. 4 points)

Back 10

1. DNA template transcribed into messenger RNA (mRNA) through transcription

2. Transcription occurs in nucleus, DNA codons in gene are converted into RNA codons.

3. mRNA translated into polynucleotides through translation

4. Translation occurs in Cytoplasm

Front 11

Process of Transcription (3)

Back 11

1. DNA unwinds/ Gene unzips

2. One side becomes the template strand

3. mRNA molecule (template copy)

Front 12

Biological Molecules in Translation (4)

Back 12

Involved:

1. Amino Acids

2. Transfer RNA (tRNA)

- each tRNA has 1 AA attached

- AA depends on tRNA's anticodon

3. Ribosomes

- help make polypeptides from mRNA

4. mRNA

Front 13

Process of Translation

Back 13

1. AA continually attached till ribosome reaches stop codon on mRNA

2. Upon stop codon, ribosome leaves mRNA

3. Completed polypeptide is produced`

Front 14

Define Genetic Engineering

Back 14

The manipulation of an organism's genetic material

1. involves transfer of genes from one organism to another through vector molecules

Front 15

Define vectors & list an example

Back 15

Vectors are DNA molecules used to carry the gene(s) to be transferred

EG. plasmids from bacteria

Front 16

The process of transferring genes

Back 16

1. Isolate the desired gene

- cut using restriction enzyme

2. Insert the gene into vector DNA

- Restriction enzyme used to cut gene used to cut vector DNA also

- The cut gene and vector DNA mixed together with DNA ligase (enzyme that joins the 2)

3. Insert recombinant plasmids into bacteria

- mix recombinant plasmids with bacteria

- temporary heat or electric shock the cells

Front 17

Diabetes is caused by

Back 17

Caused by inability of the islets of Langerhans to produce sufficient insulin

Front 18

Lareg Scale Production of Human Insulin

Back 18

1. Transgenic Bacteria need to be burst open to extract

2. To obtain large amounts, large amounts of transgenic bacteria must be cultured

3. Done through large sterile containers (fermenters) (opt. conditions for growth)

Front 19

Applications of Genetic Engineering (3)

Back 19

1. Creation of Transgenic Plants

- Resistant to Pests and Herbicides

2. Gene Therapy

- Healthy genes transferred from one person to another with defective genes

Front 20

Selective Breeding (4)

Back 20

1. Organisms involved must be closely reltaed or same species.

2. Possibility of transmitted defective genes to offspring.

3. Slow process; many generations.

4. Less efficient, grow slowly, may need more food

Front 21

Genetic Engineering (4)

Back 21

1. Genes from any organism can be inserted into non related.

2. Selection of genes before transfer eliminates risk of defective gene transfer.

3. Process where individual cells reproduce rapidly in a small container in laboratory.

4. More efficient, transgenic organisms grow faster, may need less food

Front 22

Advantages of genetic engineering (4)

Application + Advantage

Back 22

1. Low cost production of medicines

- Drugs more affordable

2. Crops that grow in extreme conditions

- grow crops in enviro conditions not favourable for cultivating most props

3. Pesticide-Resistant Crops

- Use of costly pesticides that dmg enviro is reduced

4. Foods designed to meet specific nutritional goals

- Nutritional quality improved

Front 23

Disadvantages of Genetic Engineering (4)

Back 23

1. Environmental Hazard:

- GM crops produce insect toxins

- death of insects

- loss of biodiversity

2. Economic Hazard:

- If prices not regulated for GM seeds

- poorer farmers cannot afford

- while the richer get even richer through technology

3. Health Hazard:

- Genes that code for antibiotic resistance

- accidentally incorporated into bacteria that cause human diseases

4. Social & Ethical Hazards:

- GE lead to class distinctions

- some religions disapprove

- not appropriate to alter natural genetics of organisms