Biology Discussion Notes

Tuesday 1/13/2015

Goals for the day1. Be able to describe a karyotype and what

they might be used for

2. Be able to determine whether a karyotype belongs to a male or female by identifying and interpreting the sex chromosomes.

3. Be able to describe what could happen if something goes wrong in meiosis

Question of the Day 1/13

How does Meiosis differ in males & females?

Meiosis in males makes

4 equal sperm

Meiosis in females makes 1 huge egg

Sex Chromosomes• X & Y are the “sex” chromosomes, they

determine if you are male or female people have two (Usually). This is just 1 of your 23 pairs of chromosomes.

• What two sex chromosomes do males have?

• What two sex chromosomes do females have?

Sex Chromosomes

“Who” determines whether the baby will be a boy or a girl (Mom or Dad)?

Males Females

Karyotype – a picture of chromosomes

Males – XY

Females XX

Non-Disjunction

• Junction?

• DisJunction –

• Non-Disjunction -

Non-Disjunction

Non-Disjunction

Karyotyping- Amniocentesis

Karyotyping Lab• Work in groups of 2 or 3

• Start helping each other cut• As you accumulate chromosomes one person can

start matching & pasting• Work on questions once you have all your

chromosomes on.• EXTRA CREDIT OPTION:

– When you are finished look up other syndromes caused by having to few or to many chromosomes. – write them down & describe them for extra credit on your lab sheet

Business• Skills Check tomorrow – VERY similar to

practice skills check, so if you have a question on that ASK IT!

• Meiosis Reading Guide –DUE TOMORROW – Only accepted if 100% complete!

Species of the Day 1/13• Downy Woodpecker

– Picoides pubescens

Species of the Day 1/13• Downy Woodpecker

– Picoides pubescens