Core – Practice test 4

Genetics

Remember what an inference is?

• An explanation based on observations

Sexual VS Asexual Reproduction

• Sexual – two parents

• Meisois

• Testies and ovaries

• Fusion of egg and sperm to form a zygote

• seeds, flowers

• Increase variation

• Evolution

• Changing environments

• Asexual – one parent

• Mitosis

• Somatic, body cells

• Cloning

• Exact copy

• No variation (unless mutation)

• Produce many offspring

A normal human cell has 46 chromosomes. After a cell undergoes

meiosis, how many chromosomes will the resulting cells have?

• 23

• In which organ of an animal's body would

meiosis occur?

• Testis and ovaries

• In a plant?

• flower

In changing environments, is asexual or sexual better?

• Sexual. Why?• The increase in genetic

variability.• Why would some grasses be

able to grow on ground polluted by an oil spill

• Genetic variation within the grass species allows some to survive and reproduce.

What do you know about the Irish Potato Famine?

• 1845 A fungus like protist destroyed the Irish potato crop which was the main source of food for one third of the population. This led to a 7 year famine. Why did one little fungus cause so much trouble?

• Potatoes grow by asexual reproduction therefore the potatoes lack variations that could have withstood the infection.

When environmental conditions are bad or change, is sexual or asexual reproduction better?

• Sexual reproduction

• Why?• It increases genetic variation (like having more

choices).

How does asexual reproduction help the survival of a species

• Asexual reproduction may result in many offspring with the same strong useful characteristics as the parent.

• Mushroom reproduce by producing– • spores• Bacteria reproduce by– • fission• Hydra – • budding• Tulips (and things with bulbs) – • vegetative

Forms of Asexual Reproduction

Reproduction/Plants

• Is it better to reproduce with spores or seeds?

• Seeds• Why?• Seeds contain stored

nutrients for nourishment and a hard protective coat.

Chromosome number

• In sexual reproduction (meiosis) what happens to the chromosome number?

• It is cut in half (humans 46 to 23)

• In Asexual reproduction – chromosome number?

• Stays the same.

From DNA to Protein

DNA vs. RNA

• DNA (where?)• Nucleus only• How many strands?• Double stranded• What type of sugar?• De oxy ribose• Bases are . . . . . • A-T and • G-C

• RNA (where)• mRNA from nucleus to

cytoplasm• tRNA and rRNA – cytoplasm• How many strands?• Single stranded• What type of sugar?• Ribose• Bases?• A-U• G-C

What does DNA look like?

• A twisted latter.

How were discoveries of DNA made?

• A lot of people involved.

• Watson, Crick, Wilkins, Franklin and more

• What did they do?

• They did many experiments and Watson and Crick made a model.

Central Dogma

• What is Replication?• DNA to DNA• Where?• Nucleus• What is Transcription?• DNA to mRNA

• Where (transcrition)• Nucleus• What is Translation?• RNA to Protein• Where?• Cytoplasm on the

Ribosome

DNA to Protein

How does DNA get from the nucleus to the ribosomes?

• It jumps

• Just kidding – mRNA (messanger RNA) takes the message from the nucleus to the ribosomes.

Patterns of inheritance1. Which trait usually shows dominant or

recessive?2. dominant3. Wavy hair is where both are dominant or

_________ dominance.4. codominance5. If I cross a white and red flower and get

pink. What is this?6. Incomplete dominance

inheritance

• Eye color, hair color, height is what type of inheritance?

• Polygenic

• Blood type is what type of inheritance?

• Multiple allelic and codominance

Words to know

• Hetero zygote• Different - Rr• Homo zygote dominant• Same - RR• Homo zygote recessive• Same - rr

• Gene o type• Genes RR, RR, rr• Pheno type• Physical stuff – red,

white, tall, short

Punnet Squares

• If you cross a Green pea with a yellow pea and get all green peas, why is this?

• Green is dominant over yellow.

• Then, if I cross these kids, what will happen?

G G

g Gg Gg

g Gg Gg

G g

G GG Gg

g Gg gg – some yellow will show up

Genetic Technologies

• And genetic engineering.

Selective breeding is also called what?

• Artificial Selection.

• Why?

• Humans select for certain traits instead of nature (as in natural selection)

• An orchard in California makes really great oranges. They want to maintain this high quality. How should they do this?

• Clone the trees – Take cuttings from the already fabulous trees and make trees.

What is the process called when an egg is removed, fertilized outside of the body, and then implanted in the

womb?

• in vitro fertilization

Selective breeding

• Also called• Artificial selection• Breeder/farmer chooses only the best animals or

crops• Examples• Corn Hybrid• Race horses• Shetland pony• Siamese cat

Genetic technologies

• How do we do genetic testing on fetus?

• Amniotic fluid can be taken to diagnose prior to birth (and possibly fix)

DNA profiling (CSI)

• Also called?

• DNA fingerprinting and

• Gel electrophoresis

• Used for?

• Identify the killer

• Who’s the dad?

Gene Therapy

• Also called?• Recombinant DNA?• What is it?• Insert a foreign gene

into a host • Being used for• (cystic fibrosis)

• Use bacterial plasmids to make?

• Insulin• Human Growth

Hormone (HGH)• Interferon• Other stuff.

Other Genetic technologies

• Cloning

• Increase food supply, improve health, better medicines, transplants etc.

• Stem cell research

On the board

• Punnet squares and pedigrees.