3. Genetics

Question 1

3.1 What is a gene?

Answer 1

A sequence of DNA nucleotides that codes for heritable characteristics

Question 2

3.1 What is a gene loci?

Answer 2

Where a gene is located on a chromosome

Question 3

3.1 What is an allele?

Answer 3

A version of a gene

Alleles are located at the same locus with a slightly different sequence of nucleotides

Question 4

3.1 Types of substiution mutations

Answer 4

Silent, Nonsense, Missense

Question 5

3.1 What is the relevance of the COX gene?

Answer 5

a gene for cellular respiration that is present in most Euk. organism, allows for easy comparison of sequences

Question 6

3.1 What is the cause of sickle cell amenia?

Answer 6

A substiution in the gene to make hemoglobin

Question 7

3.1 Steps of Sickle Cell Anemia

Answer 7

The irregular hemoglobin causes the blood cell to bcecome a sickle shape which gets stuck in blood vessels –> anemia = not enough healthy cells to deliver o2

Question 8

3.2 Describe Prokaryotic DNA

Answer 8

Known as the nucleoid, prokaryotic DNA is not enclosed, is a single naked loop

Question 9

3.2 What is a nucleus

Answer 9

The Eukaryotic’s membrane bound organelle containing DNA

Question 10

3.2 What is a nucleolus?

Answer 10

Structure in the nucleus responsible for ribosome production and assembly

Question 11

3.2 What is a nucleosome?

Answer 11

Small lengthes of DNA wrapped around 8 histone protiens (building blocks of chromatins)

Question 12

3.2 What is Chromatin

Answer 12

Loose form of DNA (chromosome material) not supercoiled, durng interphase

Chromosome = yarn ball
Chromatin = yarn string

Question 13

3.2 What is a chromosome?

Answer 13

The supercoiled form of chromatin

Question 14

3.2 What is a chromatid?

Answer 14

One side of a copied chromosome (arms of the same length)

Question 15

3.2 Diploid vs Haploid

Answer 15

Diploid: Cell containg two complete sets of chromosomes, one from each parent

Haploid: One copy of each chromosome (sp, egg)

Question 16

3.2 Heterosomes vs Autosomes

Answer 16

Autosomes - normal
Heterosomes - determine sex (x vs Y)

Question 17

3.2 Homologous chromosomes

Answer 17

Share same structure, same genes at loci position (alleles can be different
- seperated

One comes from maternal, one from paternal

Question 18

3.2 Chromosomes in Species

Answer 18

Organisms with different #s of chromosomes can’t interbreed

Question 19

3.2 What causes species to have different #s of chromosomes?

Answer 19

• Splitting
• Fusing
• Evolution

Question 20

3.2 What is a karyogram?

Answer 20

A micro-photograph of all the chromosomes for an individual

Question 21

3.3 Whats the difference between Meiosis 1+2

Answer 21

M1: Diploid to haploid, 2 products, crossing over, procceded by DNA replication

M2: Haploid to haploid, 4 products, chromatids seperate, no crossing

Question 22

3.3 DNA through meiosis

Answer 22

G1: single, non-super coiled DNA
S: 2 pairs of sister chromatids, homologous chromosomes
Prophase 1: DNA supercoils
Metaphase 1: Homo chromos at equator, crossing over
Anaphase 1: Seperate
Telophase 1: At poles, still with sister
Prophase 2: Supercoil again
Metaphase 2: Equator, not paired
Anaphase 2: Seperate
Telophase 2: Decondenses

Question 23

3.3 Does crossing over happen in Mitosis or Meiosis?

Answer 23

Meiosis

Question 24

3.3 What happens during prophase 1, meosis?

Answer 24

1) Pairing of homo chromos through synapsis : homochoromos attach at chiasmata (attachment sites) to form bivalent

2) Homo chromoes exchange pieces of non-sister chromatids @ chiasmata

Question 25

3.3 Formula for possible chromosome combinations -

Answer 25

2^n (n is the number of chromosomes in haploid)

Question 26

3.3 What is nondisjunction?

Answer 26

Failure of homo chromos to seperate, result = abnormal numbers

Question 27

3.3 Draw the Process of Meiosis

Question 28

3.3 Describe Two Methods of Fetal Cell Karotyping

Answer 28

1) Aminiocentesis- amnotic fluid is collected via needle in abdomen 2) Chronic Virus Sample - thin tube inserted for sample of placenta

Question 29

3.3 What promotes genetic variation in Meiosis?

Answer 29

Crossing over and random orientation

Question 30

3.4 What is Mendel's Experiemtn

Answer 30

Through selectively breeding pea plants learned 1) Genes passed to offspring 2) One gene per parent 3) Recessive genes

Question 31

3.4 Types of Allele Combinations (Dominancy)

Answer 31

1) Dominant/Recessive 2) Codominant 3) Sex-Linked

Question 32

3.4 What allele type is sickle cell anemia

Answer 32

Codominant, red blood cell disease

Question 33

3.4 What allele type is Red-Green Color Blindness?

Answer 33

Recessive, sex linked

Question 34

3.4 What type of allele is Hemophillia?

Answer 34

recessive, sex-linked (X)

Question 35

3.4 What type of allele is Cystic Fibrosis

Answer 35

recessive

Question 36

3.4 What type of allele is Huntington's?

Answer 36

Dominant

Question 37

3.4 What are gametes?

Answer 37

Haploid cells with one allele of each gene, fuse together to create zygote

Question 38

3.5 Descibe the process of gel electrophoresis

Answer 38

DNA samples are put in sample wells at the end of gel. These DNA samples are cut smaller, and naturally have a negative charge. Molecules move towards the positive electrode on the other end based on size with smaller molecules going farther (since they go faster). This creates a band to help identify.

Question 39

3.5 What is the purpose of PCR?

Answer 39

Polymerase Chain Reaction is used to make many copies of DNA

Question 40

3.5 What are the steps of PCR?

Answer 40

1) Denaturation 2) Annealing (cooling, primer binds) 3) Extension (Raise temperature to trigger TAQ polymerase)

Question 41

3.5 What are the steps of DNA Profiling?

Answer 41

1) Sample of fluid collected 2) Reference sample collected 3) PCR used to make multiple copies 4) DNA is cut into fragements using restriction endonucleases 5) Electrophoresis 6) Bands are compared

Question 42

3.5 What is cloning and how?

Answer 42

A clone is asexually produced via: - Binary Fission - Budding (cells splitting off) - Fragementation (Seperated fragement) - Parthenogenesis (unfertilized egg) - Splitting of embryo

Question 43

3.5 Describe Gene Transfer using Bacteria (for insulin)

Answer 43

- mRna is extracted from human pancreatic cells and using rever transcriptatse it becomes complementary DNA - Plasmid is obtained from bacteria and cut with restrictive enzume - Plasmid and cDNA fused together using DNA ligase - Reintroduced to host cell

Question 44

3.5 What is the process of Somatic Cell Cloning?

Answer 44

The nucleus from the somatic cell with desired genes is removed and placed in egg cell with its own nucleus thats been removed (nucleus replacement)

Question 45

3.5 What are the pros and cons of GMO crops?

Answer 45

Pros: - less insecticides - Longer shelf life - Increased nutrients - More resistant Cons: -protiens could be toxic -antibiotic resistant plasmids could spread -contamination - biodiversity risk