Download Cells - WordPress.com

Using a microscope, I have developed my
understanding of the structure and variety of
cells and of their functions
Cells
A3
WHAT YOU NEED TO KNOW:

All living organisms are made from cells. Huge numbers of different types
of cells exist, but they can be catagorised into “plant” or “animal”.

Both plant and animal cells contain:
o A Cell Membrane- the boundary of the cell
which allows chemicals to move in and out
o Cytoplasm- the watery gel inside the cell
where the chemical reactions happen
o A Nucleus- contains the genetic information
and controls the cell in all it does
 Plant cells also contain chloroplasts, where photosynthesis takes place, a
vacuole, which contains the cell sap and a cell wall which makes the cell
rigid and regular in shape.
 Multicellular organisms contained cells which are specialised to carry out
different jobs, such as:
o
root hair cells- have a larger surface area to absorb water
o
sperm cells- tail and streamlined to help movement, and a
special head to burrow into the egg
o
nerve cells- have long axons to transmit electrical signals
CAN YOU:
1. Label both an animal and plant cell and
say what each part does?
2. Give examples of specialised cells and
say how they are adapted?
Microbes
A3
I have contributed to investigations into the
different types of microorganisms and can
explain how their growth can be controlled.
WHAT YOU NEED TO KNOW:

Microbes are organisms that are too small to be seen without a microscope,
eg, bacteria, fungi, viruses and algae.

Microbes affect every part of our lives- they can be useful or cause
problems.

USEFUL MICROBES
 Breaking down of waste in compost
 Bacteria are used to make yoghurt and cheese
 Yeast makes alcohol and makes bread rise
 Fungi make antibiotics

NOT SO USEFUL MICROBES
 Bacteria, yeasts and moulds make food “go bad”
 Bacterial infections- Food poisoning, tuberculosis, cholera
 Yeast infections- thrush and athletes foot
 Viral infections- Chicken pox, the flu, measles, the cold

Microbes growth can be controlled by changing the temperature, as seen
when breadmaking.
o At low temperatures, the yeast multiply slowly, and the dough does not rise.
o At around 40oC, the yeast will multiply and react faster, turning sugar into
alcohol and carbon dioxide, which casues the dough to rise.
o When the bread is baked at high temperature the yeast will be killed.

Improved sanitation and treatment of sewage prevents the spread of
water-borne diseases such as cholera.

You can stop diseases spreading by covering your mouth when coughing,
cooking food well, using soaps/antiseptics, covering cuts with plasters

CAN YOU
1. Name 3 types of microbes and give examples of how they are either
useful or cause problems to humans?
2. Explain how to control the rate at which microbes reproduce?
3. Suggest ways to prevent diseases spreading, and explain how each works?
A3
Stopping infection
I have explored how the body
defends itself against disease and
can describe how vaccines can
provide protection.
WHAT YOU NEED TO KNOW:

Microorganisms that cause disease,
pathogens, may infect the body to
cause illness or death.

There are several
different defence
mechanisms that
the body uses to
stop microbes
getting into the
body:

Once microbes are in your body, the
immune system starts to work in two ways:
o White blood cells engulf (surround and digest) microbes
o Other white blood cells make antibodies, which attach to the
pathogen, and make it easier to be destroyed.
 You can be immune (protected against a specific disease):
o If you have had the disease- your body remembers it, so the next
time you are attacked, antibodies are made quickly and you don’t get
ill
o By having a vaccine- a weakened or dead version of the disease.
This causes antibodies to be made, and you are protected when the
disease enters the body.
CAN YOU:
1. State how diseases are stopped from entering the body?
2. Explain the 2 ways in which White Blood cells act to kills Pathogens?
3. Describe what “immunity” is, and how you can be immune to a
disease?
Body systems
A3
I have explored the structure and function of
organs and organ systems and can relate this
to the basic biological processes required to
sustain life.
WHAT YOU NEED TO KNOW:

Our body is made up of several different systems that depend on each
other and contribute to our health and wellbeing.

Each system is made up of several different organs that work together:
Name of system
 The Respiratory
system
 Digestive system
Organs include
Nose, mouth, windpipe,
lungs
Mouth, oesophagus,
stomach, liver, intestines
 Circulatory system Heart, blood vessels
 Reproductive
system
 Nervous system
Sex organs (ovary, womb,
testes, penis)
Nerves, Brain, spinal cord
What it does
Allows you to breathe
Breaks large insoluble
food into nutrients
Transports blood
throughout the body
Allows humans to have
babies
Communication between
brain and body

Many different systems work together to maintain body function.

The Digestive system, Respiratory system and Ciculatory system work together to allow
all cells to respire:

CAN YOU
1. Name different systems and the organs that they are made up from?
2. Explain what each system does in the body?
3. Give examples of how different systems work together to keep the body
working?
Fertilisation
I understand the processes of fertilisation and
embryonic development and can discuss
possible risks to the embryo.
A3
WHAT YOU NEED TO KNOW: .

Fertilisation occurs when a male sex cell joins together with a female sex cell . In
mammals, this is when a sperm joins with an egg or ovum in fallopian tube (oviduct) of
the female reproductive system.
Oviduct
(fallopian
tube)

Uterus/
womb
The fertilised egg will start to divide into two cells, then four, then eight, etc., until
there is a ball of cells. It then moves along the oviduct or fallopian tube, and attaches
to the side of the womb, where the embryo develops.

Some of the cells that are embedded in the womb form the placenta. The Placenta
carries oxygen and nutrients from the mothers blood to the embryo, and waste products
back.

The development of the embryo can be affected by a variety of different
factors. Chemicals such as alcohol, drugs and those found in cigarettes can
cause development problems. These can be passed from the mothers blood
to the embryo through the placenta.

CAN YOU
1. Label the different parts of the reproductive system and state what
they do in reproduction?
2. Describe how a fertilized egg develops into a baby?
3. Give examples of factors that affect a baby developing?
I have extracted DNA and understand its
function. I can express an informed view of the
risks and benefits of DNA profiling.
Inheritance
A3
WHAT YOU NEED TO KNOW: .

Most human cells contain 23 pairs of
chromosomes
in
the
nucleus.
Chromosomes are all made up of
thousands of genes, which are made
from DNA.

No two humans have exactly the same DNA, apart from identical twins, and this makes
us have a unique genetic fingerprint.

Your unique DNA sequence can be analysed from a body fluid sample. Forensic scientists
can match the DNA taken from a crime scene with suspects DNA profiles to determine
who committed the crime.

DNA can also be used in finding out who the biological father is if there is a dispute, or
seeing if people have a risk of passing on an inherited disease to their offspring.

Egg and sperm cells only contain 23 individual chromosomes, so when an egg is fertilised,
23 pairs are made. Half of your genes come from your dad and half from your mum.

The combination of the two genes decides the baby’s features. If you have 2 different
genes for a characteristic like hair or eye colour, one colour is usually dominant over the
other, and that colour will feature.
Jim has inherited 2 blonde
hair genes from his parents

John has inherited 2 dark
hair genes from his parents
Jess has inherited 1 gene
of each from her parents
but dark hair is dominant
Whether you are male or female depends on the two sex chromosomes you inherit. All
females have 2 X chromosomes, so can only pass on an X chromosome to their children.
Males have an X and a Y chromosome, so can pass on either one to their children.

CAN YOU
1. Describe where DNA is found and why each person has a unique profile?
2. Explain why characteristics are inherited?
3. Explain how gender is due to which sex chromosomes you have?
Down:
Down
1 basic unit of inheritance that gives us
our characteristics
3 body part that is made up of several
tissues
5 the system that includes the heart and
blood vessels
7 this cell destroys body invaders
10 the cell____________ allows
movement of substances to and from the
cell
11 breaking down food into small soluble
nutrients
14 weakened or dead microbes which are
used to give protection against infection
15 being able to resist a particular
infection
16 the organs that help oxygen enter your
bloodstream
Across:
2 where the fertilised egg implants and develops
into a baby
4 a living thing in the early stages of
development
6 the process that happens when a sperm joins
an egg
8 found in plant cells to keep shape
9 a disease-causing organism
12 the basic building block of living things
13 the reaction that happens in cells to release
energy from food
17 the part of a cell where the chemical
reactions take place
18 a chemical which attaches to an invader to
allow detection
19 a living thing that can only be seen with a
microscope
20 controls the cell function
Best to print back to back, dual page:
Print 7,8, 5,2
Then turn over and do 3, 4,, 1, 6