FUNBIO 15 - Genetics as information flow, the human genome; DNA structure and replication

Question 1

Define Heredity.

Answer 1

The passing on of physical or mental characteristics from one generation to another.

Question 2

Define Genetics.

Answer 2

The study of genes, genetic information, and heredity in living organisms.

1. The flow and handling of genetic information in biological systems.
2. Storage and preservation of information (DNA)
3. Use and handling of information through gene expression (RNA and proteins).

Question 3

Genotype vs. Phenotype

Answer 3

Genotype is the genetic constitution of a cell.
Phenotype is the observable constitution of an organism.
Phenotype = Genotype + Environment

Question 4

Explain DNA replication for the leading strand.

Answer 4

1. DNA Helicase separates the two strands of DNA.
2. Primase makes an RNA primer out of RNA bases.
3. DNA Polymerase binds to the RNA primer and begins adding DNA bases to the strand in the ‘downstream’ direction (5’ end –> 3’ end)

Question 5

Explain DNA replication for the lagging strand.

Answer 5

1. Primase makes an RNA primer out of RNA bases.
2. DNA polymerase binds to the RNA primer and adds a short strand of DNA bases to the strand in the ‘upstream’ direction (3’ end –> 5’ end) called an Ozaki Fragment.
3. Primase makes another RNA primer out of RNA bases further down the strand.
4. DNA polymerase creates another Ozaki Fragment after binding to the RNA primer.
5. Eventually, Exonuclease removes all RNA primers on the strand and DNA ligase fills in the gaps between the Ozaki Fragments.

Question 6

How many chromosomes do human cells have?

Answer 6

• 23 pairs of autosomal chromosomes (46 in total)

- 1 pair of sex chromosomes (MALE: XY) (FEMALE: XX)

Question 7

Describe the structure of DNA.

Answer 7

Two polynucleotide strands wound about a common axis with anti-parallel orientation. The sugar-phosphate backbones are on the exterior, while the purine and pyrimidine nucleotide bases are in the interior.

Question 8

Classify the DNA bases and their complementary pairs.

Answer 8

Purines: Adenine & Guanine
Pyriminides: Thymine & Cytosine
Adenine binds with Thymine & Guanine binds with Cytosine.

Question 9

Explain DNA ends.

Answer 9

DNA has 2 ends: 5’ end & 3’ end

• Moving in the direction from 5’ to 3’ is DOWNSTREAM (DNA replication for leading strand).
• Moving in the direction from 3’ to 5’ is UPSTREAM (DNA replication for lagging strand).

Question 10

List the types of Genetic Testing (CNDFPP).

Answer 10

1. Carrier Testing
2. Disease Testing
3. Newborn Screening
4. Forensic Testing
5. Prenatal Testing
6. Predictive Testing

Question 11

What is Cystic Fibrosis?

Answer 11

An autosomal recessive hereditary disease that affects the lungs and digestive system, caused by a mutation in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene.
Gene therapy has been used to treat CF through the use of viral and lipid vectors delivered to the lungs.

Question 12

What is gene therapy?

Answer 12

• The introduction of foreign genes into a cell in order to exert a therapeutic effect. There are three types being tested:
  1. Replacement
  2. Removing
  3. Introduction
• Gene therapy is possible through
  1. vectors: adenoviruses
  2. lipids & proteins

Question 13

What is the Human Genome Project?

Answer 13

Established in 1990 by James Watson and completed and published in 2003, it aims to map the entire human genome.

Question 14

What is DNA fingerprinting?

Answer 14

Utilizes repeating sequences of DNA on a chromosome known as Variable Number of Tandem Repeats.