Transcript Multicellular Organisms

Multicellular
Organisms
National 4
Unit 2
Germination
For seeds to germinate (i.e. grow),
they need particular conditions:
Water
Oxygen
Warmth
Propagation
Propagation is the process by which a
grower increases the yield of a
particular plant.
There are two methods of propagation:
Vegetative
Artificial
VegetativePropagation
Vegetative propagation is a form of
asexual reproduction in plants.
This means that the offspring formed
through this type of propagation will be
identical to the parent plant (a clone).
Why is this important?
Vegetative Propagation
Examples:
Bulbs are an example of
vegetative propagation. An
example of a bulb is an
onion. They act as a food store
for the plant to grow from the
Bud
(Will grow
Into a new
plant)
bud.
Vegetative Propagation
Examples:
Tubers are another example of
vegetative propagation which act
as a food store. An example of a
tuber is a potato.
Vegetative Propagation
Some plants, like the strawberry plant, produce
miniature plants called plantlets attached to the
parent.
The plantlets obtain food from the parent plant
until they
have produced roots and can absorb water and
minerals from the soil.
Growing Plants
Some plants can be sheltered to allow us
to control the conditions they are grown
in and protect them.
Polythene tunnel
Greenhouse
Genetics
We all receive one allele for each characteristic from
our mother and one from our father
The allele that is expressed in the phenotype (the
physical appearance) is known as the dominant
allele and the other as the recessive allele
The dominant allele is represented by a capital letter
and the recessive by a lower case.
Genetics
If the alleles that an individual receive
from their parent are the same, they
are said to be homozygous.
If the alleles from each parent are
different
then they are said to be
heterozygous.
Genetics
For example:
Purple petals (P) is dominant to
yellow petals (p).
If a true-breeding (homozygous)
purple plant is crossed with a
yellow plant, the offspring will all
be yellow.
Insulin
Insulin is a hormone that allows our body cells to
absorb glucose from our blood.
Special cells (called beta cells) in the pancreas
produce insulin and release it into the
bloodstream.
When we eat a meal, the level of glucose in our
blood increases. This leads to a rise in insulin.
Insulin
On occasion, the pancreas may not
produce enough insulin or our body cells
may stop responding to it.
This leads to diabetes and means we
cannot control the amount of glucose in
our blood.