Meiosis Big Picture

What is the purpose of meiosis?

WHY must there be 2 cell DIVISIONS in meiosis?

Why is Crossing Over an important step in meiosis?

At the end of meiosis we either get 4 viable sperm cells or 1 viable egg cell. Why is there a discrepancy?

What is the long-term advantage of sexual reproduction?

What is the purpose of meiosis?

• to allow organisms to grow and develop

• to heal and repair worn out cells

• to produce sex cells for reproduction

• to create identical cells for cloning

WHY must there be 2 cell DIVISIONS in meiosis?

• because the DNA is copied twice and 2 divisions will reduce the chromosome number to normal

• because the sex cells must be haploid and have a one copy of each chromosome

• because the sex cells need 2 copies of the DNA

• one division creates the sperm and the other division creates the eggs

Why is Crossing Over an important step in meiosis?

• it speeds up the process of meiosis

• there is a better chance of fertilization

• it causes twins to occur more often

• it allows for greater genetic diversity

At the end of meiosis we either get 4 viable sperm cells or 1 viable egg cell. Choose 2 reasons why creating 4 equally-sized, small sperm cells is a good biological strategy.

• tens to hundreds of millions of sperm are released in a single ejaculation

• they need to be small enough to all fit inside the egg once they get there

• they only need to be large enough to carry the chromosomes to the egg

• because half can make male offspring and half can make female offspring

At the end of meiosis we either get 4 viable sperm cells or 1 viable egg cell. Choose 2 reasons why creating 1 large, viable egg cell is a good biological strategy.

• because the polar bodies are useless and die off

• because most of the cytoplasm can go to the egg to sustain it if fertilized

• because women only need to release 1 egg cell per month

• because the egg will continue to grow larger and larger until the sperm fertilize the egg