N5 Biology Cell Biology subunit 3 DNA and Making New Cells

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Transcript N5 Biology Cell Biology subunit 3 DNA and Making New Cells

N5 Biology
Cell Biology subunit 3
DNA and Making New Cells
Making New Cells
simple
cell division
diagram
membrane
nucleus
nucleus
membrane
nucleus
nucleus
nucleus
Species
human
chromosome Number of
complement matching pairs
46
fruit fly
8
4
snail
54
27
cabbage
18
9
23
Duplicated chromosome
centomere
chromatids
Stages of Mitosis
Click here for mitosis animation http://www.cellsalive.com/mitosis.htm
More Mitosis Animations
Click here for Time lapse film of mitosis (1.30 mins)
http://www.bbc.co.uk/learningzone/clips/cell-division-bymitosis/4189.html
Click here for you Tube video (10 mins)
http://www.youtube.com/watch?feature=player_emb
edded&v=L0k-enzoeOM#!
Stages of Mitosis
text from pupil booklet
When the chromosomes become visible they appear as double
threads called chromatids joined by a centromere.
Structures in the cell called centrioles migrate to opposite
ends of the cell - the ‘north and south poles’.
The membrane round the nucleus disintegrates and the
chromosomes line up along the equator – in between the north
and south poles.
Spindle fibres from the centrioles attach to the centromere
of each chromosome. The spindle fibres shorten and pull the
chromatids apart. One chromatid from each pair moves to
the north pole and the other one moves to the south pole.
Two new nuclei form when the nuclear membrane forms round
each set of chromatids – now called chromosomes. The cell
then divides in two
Looking at Dividing Cells
You may see some cells under the
microscope like some of the cells below
Looking at Dividing Cells
Cell production
Click here for film showing how new skin cells are grown (3.09 mins)
http://www.bbc.co.uk/learningzone/clips/growing-new-skin-cells/111.html
Click here to see a Youtube film of AsepticTechniques while transferring
culture medium from a bottle to an agar plate
(only watch from start to 6 mins)
http://www.youtube.com/watch?v=gQvZ4opDcno&feature=player_embedde
d
Aseptic Technique
technique
heat glassware in an autoclave
(pressure cooker) to 121oC
wash hands before and after
experiment
hold lid over open petri dish
reason
sterilise equipment
remove microorganisms
from skin
prevent entry of unwanted
microbes
flame innoculating loop
destroy unwanted microbes
on wire
lids held onto inoculated petri
dishes with tape
prevent entry OR exit of
microbes from agar
surfaces disinfected before and
after experiment
kill microbes on work area
DNA and Genes
• A gene determines an organisms
characteristics.
• Genes are found on chromosomes
.
• Chromosomes are found in the nuclei of
all cells.
• Chromosomes are threadlike structures
made from DNA
.
DNA
nuclei
chromosomes
gene
DNA Structure
weak hydrogen bond
deoxyribose sugar
phosphate
base
nucleotide
strong
chemical
bond
double stranded DNA
Click here for website with template and instructions for origami DNA
model
http://www.dnai.org/teacherguide/guide.html
Finished product should look like this
DNA discovery
Click here for Youtube video
http://www.youtube.com/watch?v=7yE3Z5f7i0&feature=player_embedded#!
DNA: The secret of life, a programme about the race to uncover
the structure of DNA. Contains interviews from the scientists
involved in the discovery (53mins)
Click here for DNA Timeline Activity
http://www.dnai.org/teacherguide/guide.html