Genome, genes and alleles

Question 1

What is a genome?

Answer 1

Each genome is the sum total of an organism’s DNA and is expressed as the base sequence of the haploid set of chromosomes.

Question 2

What is the purpose of the human genome project?

Answer 2

To identify and sequence the human genome. To provide a complete and accurate sequence of the 3 billion DNA base pairs that make up the human genome and to find all of the estimated 20,000 to 25,000 human genes.

Question 3

What are the benefits of the HGP?

Answer 3

• diagnosis: data from the HGP provide more accurate diagnoses of inherited disorders
• prevention: identifying genetic factors that predispose some people to disabling conditions
• treatment
• human biology
• human evolution

Question 4

What is a gene?

Answer 4

A section of DNA, with a unique sequence thats codes for a particular protein.

Question 5

What is genomics?

Answer 5

Comparative study of the genomes of several species.

Question 6

What is DNA made up of?

Answer 6

DNA is made up of molecules called nucleotides. Each nucleotide contains a phosphate group, a sugar group and a nitrogen base.

Question 7

What is gene sequencing?

Answer 7

The identification of the exact sequence of nucleotides in a gene.

Question 8

What is the function of a gene?

Answer 8

To code for the production of proteins.

Question 9

What are the purines?

Answer 9

Adenine and Guanine. They have two rings.

Question 10

What is a nucleotide?

Answer 10

The building block of DNA. Consists of a phosphate group, a base and a sugar.

Question 11

What type of bonds are found between base pairs?

Answer 11

Hydrogen bonds.

Question 12

What are the pyrimidines?

Answer 12

Cytosine and thymine. They have one ring.

Question 13

What is the only direction that DNA can be replicated?

Answer 13

It can only be replicated in a 5’ to 3’ direction.

Question 14

What are the requirements of DNA replication?

Answer 14

• original DNA template
• free dna nucleotides
• DNA polymerase
• Primers

Question 15

What occurs during the first stage of DNA replication?

Answer 15

1. dna is unwound by helicase
2. dna primase binds to 3’
3. dna polymerase builds off rna to create bases. Lagging strand replicates with multiple primers creating okasaki fragments
4. exonuclease removes rna primase and replaces them with bases. Then proofreading occurs
5. Ligase joins okazaki fragments

Question 16

What is the 5’ prime direction?

Answer 16

One chain of nucleotides runs from ‘head-to-tail’, with a phosphate group at the ‘head’ end, known as the 5′ end and a sugar molecule at the ‘tail’ end known as the 3′end.

Question 17

What is another name for the dna chains running in opposite directions?

Answer 17

Anti parallel.

Question 18

What is a complementary base pair?

Answer 18

The base pair between two strands of DNA. A-T and G-C

Question 19

What does the term dissociation mean when referring to DNA?

Answer 19

The hydrogen bonds are easily broken with a low input of energy. If a solution of DNA is heated to 90 °C for 2 minutes, each double helical DNA molecule separates into single chains.

Question 20

How is DNA packed within a chromosome?

Answer 20

DNA double helix becomes tightly coiled around histones and these coils are coiled into super coils called nucleosomes.

Question 21

What is an allele?

Answer 21

An alternate form of a gene that codes for a specific trait.

Question 22

What is a locus?

Answer 22

The position of a gene along the length of a chromosome.

Question 23

What is DNA?

Answer 23

The molecule of inheritance which is composed of two nucleotide chains arranged

Question 24

What is epigenetics?

Answer 24

The study of heritable traits that are caused by chemical modifications of DNA.

Question 25

What are the disadvantages of the hgp?

Answer 25

• Privacy Issues
• Ethical Questions
• Parents will begin to determine which character their off spring shall inherit. This will snowball into the development of designer babies.