Ch 1 - Genes, Chromosomes, Heredity

Question 1

Genetics. What is it?

Answer 1

Study of heredity (When a cell will divide, how it will divide, what controls the dividing, how it’s expressed)

Transmission Genetics: how it’s passed from 1 generation to another generation. What is being passed.

Population Genetics: how populations (traits) change over time with different traits get passed on.

Evolutionary Genetics: which traits will be dominant or recessive and how the population will evolve over time

Quantitative Genetics: how different traits are inherited and passed to future generations

Question 2

What is Classical Genetics?

What is Modern Genetics?

Answer 2

1. Mendelian genetics.THIS COURSE - BIOL 2330 – how traits are passed on. ex: getting the biggest strawberries by crossing different strawberries in order to get the sweetest and biggest strawberries.
2. Study of genes at molecular level. Made possible by advances in recombinant DNA technology. Bioinformatics, Genomics, Proteomics.

Question 3

PAGE 43-55 (1.1)

Describe Mendel’s conclusions about how traits are passed from generation to generation.

Answer 3

Used genetic crosses to understand how traits were transmitted. From parents to the offspring. HIs work formed the foundation for genetics (variation + heredity)

Said another way : inheritance is a mechanism in which traits of the parents transfer into the offsprings of the next generation.

Question 4

Heredity?

Variation?

Answer 4

1. transmission of traits from 1 gen to the next.
2. shows that offspring differ somewhat in appearance (phenotype) from parents and siblings.

Question 5

Concept Questions:

What is recombinant DNA on genetics?

What is a mutation?

What is Selection?

Answer 5

Recombinant DNA : homologous chromosomes exchange genetic material during Prophase1 of meiosis.

Recombinant DNA technology can also be used to study the diseases by introducing mutant genes in the model organisms. Mutant strains of the species are analysed by the researchers to know the cause of the different diseases and disorders.

Mutation = change in genetic material (substitution, Insertions, Deletions, Translocations) Ultimate source of all variations!

Selection = allele frequency is proportional to selective advantage conferred on organisms possessing advantageous alleles.

Question 6

Chromosome Theory of Inheritance? How is it related to Mendel’s findings?

Answer 6

Inherited traits are controlled by genes residing on chromosomes. During meiosis, chromosomes segregate from each other and inherit into the offspring to maintain genetic continuity.

Genes are transmitted through gametes (sperm + eggs).

Gamets are made by meiotic cell division

Question 7

Genotype?
Phenotype?
How are these related?
How does alleles fit into this?

Answer 7

The key thing is VARIATION. If there was no variation, we would all be exactly the same!

Genotype = set of alleles that carry the info for expression for a given trait. (Ex: Ww, for a heterozygous genotype of Dominate red eyes and recessive white eyes)

Phenotype = expression of the genotype. Morphological characteristics. It’s the observable trait (Ww phenotype = we’d observe RED eyes)

Alleles = THE source of genetic variation. Different sequences arranged in a different order.

Question 8

MORE PICS FOR GENES:

Gene includes promoter AND terminator. The whole thing is a gene.

Answer 8

Translation and Transcription.
DNA to RNA to proteins.

Question 9

Transcription Review (inside of nucleus)

Answer 9

Translation review (outside of nucleus)

Question 10

Contrast chromosomes & genes.

Answer 10

1. Eukaryotes have a characteristic # of chromosomes. Called a diploid # (2n). Chromosomes in diploid cells exist in pairs (called ‘homologous chromosomes’) so humans have 2n = 2 (23 from egg and 23 from sperm) = 46
2. Gene is defined as a section of DNA that encodes for a certain trait. An allele is defined as a variant form of a gene. It determines an organism’s genotype.

Question 11

Mitosis?

Answer 11

• chromosomes are copied and distributed
• 2 daughter cells are made with a DIPLOID set (2n)

Question 12

Meiosis?

Answer 12

• chromosomes are copied and distributed
• resulting cells (gametes) receive only 1/2 the # of chromosomes. ONLY in germ cells.
• They are HAPLOID (1n) – humans, it would be only 23

Question 13

How does genetic info get encoded in a DNA molecule?

RNA

Answer 13

G to C

T to A

(except on RNA, it’s U to A)

DNA replication is semi-conservative because 1 strand is used (coding template) to make a synthesized strand (new strand). So half is synthesized and half is the original strand.

Answer: The genetic info is encoded in the form of nitrogenous bases in a DNA molecule. DNA molecules are made up of nucleotides which constitute sugar molecules, phosphate, and nitrogenous bases. Transcription is the 1st process that converts DNA sequence into an RNA sequence. When an RNA molecule is formed then it is delivered to the cytoplasm from the nucleus, and it is called mRNA. The strand of the mRNA binds to the ribosomes, and it translates to form the proteins which are expressed form of genes.

DNA

Question 14

Facts about DNA:

Answer 14

DNA FORM AND FUNCTIONS:
1. Linear polymer with varying nucleotide sequence carries genetic info
2. Double stranded structure allows for high fidelity DNA replication (semi conservative nature of replicating DNA – less mistakes)
3. Mutability
4. Grooves allow for sequence-specific interactions with proteins. Ex; RNA polymerase attaching at the promoter section of the DNA to start replication.

Question 15

Central Dogma of molecular genetics?

How is it the basis of modern genetics?

Answer 15

The central dogma of molecular biology is a theory stating that genetic information flows only in one direction, from DNA (transcription) to RNA, to protein(translation), or RNA directly to protein.

Question 16

How many different proteins, each with a unique amino acid sequence, can be constructed that have a length of 5 amino acids?

Answer 16

If there are 20 amino acids, and the length can be 5:

20^5 = 3, 200,000 possibilities

Question 17

What do restriction enzymes and vectors do when cloning DNA?

Answer 17

Question 18

Pros and Cons for patenting genetically modified organisms?

Answer 18

Question 19

How do model organisms advance our knowledge of the genes that control human diseases?

Answer 19

Example: Neurospora

Model Organism : small and easy to grow for genetic tests. Can also introduce mutations so that genetics can be studied.

• well-defined evolutionary history
• short life cycle
• matings produce many offspring
• easy to handle and extract DNA
• genetic variation between individual in population

ex: e.coli, mice, flies, yeast, c elegans (little worm),

Question 20

Name a few Biotechnology advantages with modern genetics?

Ethical Implications?

Answer 20

1. Health Care: diagnos fetus diseases
2. Supermarket products: use recombinant tech to produce disease resistant plants
3. Agriculture: increase crop yield
4. Court system: use DNA to catch criminals

ETHICS:

1. Human cloning
2. Animal cloning
3. GMO foods
4. Growth of spare body parts
5. GATTACA- genetic discrimination
6. Designer babies and reproduction technologies
7. Genetic pollution
8. Companies that have our DNA info (genetic info)

Question 21

PROKARYOTIC CELLS

Answer 21

• no mitosis
• no meiosis
• non-mendelian inheritance of genes
• divides by BINARY FISSION