nucleus and cell division

• Biologie
• Middelbare school
• vwo
• Leerjaar 1

2.5 & 2.6: The nucleus and the cell division

Planning of today

•  Repetition 2.4 cells
• Moving on to 2.5 & (maybe) 2.6: nucleus and cell division

Repetition 2.4: cells! 

Open your books page 112

What is nucleus? Where do you find that?

The nucleus

• Contains chromosomes
• Chromosomes > DNA
• Contains hereditary characteristics
• For example you eye color

What does DNA do?

DNA (Deoxyribonucleic acid)

Lots of base pairs together form genes

A base pair is made from 2 pieces, these are called bases.

T and A form a pair

C and G form a pair

Other pairs do not exist in DNA.

DNA is shaped like a ladder.

The ladder is built by using lots of  base pairs.

Try to describe what you're seeing here right now!

Cell division

Cell division is happening constantly in your body:

• 3,5 kg of new skincells every year
• 200.000.000.000 new bloodcells every day

Cells also die a lot!

• More new cells than dead cells > growth

Cell cycle

Cell cycle

• 1 daughter cell > specialised cell > heartcell, musclecell, bloodcell, etc.
• 1 dochtercel > stem cell > parent cell
• Stem cells can divide into new cells
• Stem cells don't specialise,
  but they're responsible for growth
  and for the recovery of the body 
  tissues
• Bone marrow: fat cell/bone cell/
  blood cell

skin cells

nerve cell

blood cells

embryonic stem cell

A human stem cell divides.
The daughtercells are called cell A and cell B.
How many chromosomes are in cell A? (only use numbers)

Cell A is a stem cell.
Cell A divides into cell B and C.
Cell B becomes a liver cell.
What happens with cell C?

1. Becomes a liver cell
2. Becomes a body cell
3. Becomes a stem cell
4. Impossible to tell

Homework

B5. 1, 2, 5, 7, 9 + B5. 3, 4, 8

Test yourself 2.4

Flash cards 2.4

B6. 1, 2, 4, 7