Genetics and Biotechnology Unit 8 IB Bio SL

What is the difference between two alleles of the same gene?

The order of bases in the DNA

What was the goal of the Human Genome Project?

Determine the base sequence of the human genome

Why would Bt corn impact the insects that eat corn?

Bt toxin is in the corn and pollen which is eaten by various insects which kill the insects. This is typically good unless it’s an insect needed for pollination or is close to extinction

Distinguish between eukaryotic and prokaryotic chromosomes

Eukaryote: linear, has histone proteins, no plasmids, organized into pairs

Prokaryote: Circular, no histone proteins, sometimes has plasmids, not organized into pairs

How are plasmids used in biotechnology?

• Transfer genetic information (DNA fragments)

• Can be used to produce insulin or another important protein

Outline the base substitution mutation of sickle cell anemia and the implications it has on the individual

• mRNA is altered by one base (GAG → GUG) due to the one base substituted for another in DNA (GAG → GTG)

• One codon is changed due to the change in DNA

• The change in mRNA causes tRNA to change

• Different amino acid is used to build the polypeptide (glutamic acid → valine)

• The polypeptide is changed resulting in altered hemoglobin

• Change in hemoglobin can cause the red blood cells to be sickle shaped

• Symptoms of sickle cell anemia: fatigue, shortness of breath

What determines the difference between different types of cell?

Some genes are expressed, some aren’t

If the diploid number is 18, what is the haploid number?

9

Explain how red-green color blindness is inherited.

• Sex linked (on the X chromosome)

• The r-g color blindness allele is recessive

• Heterozygous (carrier) females are not affected

• X^N = normal female

• X^n = color blindness allele

• More common in males than females because males only have one X chromosome

• If the mother is heterozygous, 50% chance son is r-g colorblind

• If the mother is homozygous recessive, 100% chance son is r-g colorblind

Distinguish between genome and proteome

• The genome (DNA) is the same in every cell within the human body (or other living organism)

• Proteome is different in each cell depending on what type of cell it is.

• For example: liver cells have different proteins than brains cells but the same DNA is found in both types of cells

Identify some methods of natural cloning

• Clones are genetically identical to the parent organism

• Type of asexual reproduction

• Found in non-vertebrates such as hydra and yeast → budding

• Another example: identical twins in humans

How is DNA from one species able to be used by a different species?

The DNA code is universal (same bases and structure in all living organisms)

Define homologous chromosomes

Two chromosomes of the same size and shape with the same genes but could have different alleles

Define PCR

Makes copies of very small samples of DNA

List benefits and risks of genetically modified crops

Benefits:

• Increase crop growth

• Less water typically needed

• Crops more hardy

• Requires less land for crop growth due to large yeild

Risks:

• GMOs may outcompete natural species of crops

• GMO crops can affect natural food chains and ecosystems

• Modified genes can pass on to other organisms

• May impact human health

Define natural cloning

• Clones typically identical to parent organism

• Asexual

• Found in non-vertebrates with yeast and hydra budding

  • Identical twins in humans

How are karyograms used in pregnancy?

• Karyograms are photographs homologous pairs of chromosomes that can be analyzed to determine if abnormalities are present and possible birth defects

• Trisomy conditions (such as Down syndrome) can be seen if there are three copies of a chromosome

• Missing or extra pieces of chromosomes can be detected

• Gender can be determined by presence of XX or XY

Draw the symbol for individual X on the diagram

Half colored circle

Calculate the probability of male Y having an allele for the disorder

50%

Explain how the information in the box labelled B indicates that the gene is not sex-linked

• If it was sex-linked it would be on the x chromosome

• There cannot be a heterozygous male if the trait is sex linked

• Males would pass the allele to their daughter

• Daughter is not shown as heterozygous so it is not sex linked

If individuals II:1 and II:2 had a third child, what is the probability that the child would have Duane syndrome?

50%

A couple have four children whose blood groups are A, B, and AB. What is the likely combination of the parent’s genotypes?

I^Ai and I^Bi

What technique was used by John Cairns to measure the length of the DNA molecule in escherichia coli?

Autoradiography

What determines the genomic size of a species?

Total amount of DNA

Which genotype would be seen in those with Huntington’s disease?

Hh