|
Cells, Digestion, Photosynthesis,
Respiration, Circulation, Ecology, Muscles & Bones.
How to revise and where to get help. The
definitive guide for GCSE students today.
How to Revise ------------
DO NOT:
 |
panic |
|
just stare at the pages |
|
copy out your text book |
|
think you can do it all tomorrow |
|
expect someone else to do it for you |
What you should be doing:
|
keep calm |
|
do what you can |
|
use your time sensibly |
|
write three lists of topics which you
|
|
know understand and have memorized |
|
understand and need to memorize |
|
need help with |
|
plan when you will do some memorizing |
|
get help from a science
teacher//parent//friend |
|
try some past papers |
This is the kind of thing you should end up
with:
"I can label a diagram of the human
digestive system and get it all correct every time because I have
memorized it. I must memorize the names of the enzymes in the mouth and
stomach, I understand what they do but I didn't bother to memorize it
for homework last year. I will do this next Tuesday evening. I really
don't understand what happens to the food after it has been digested; I
know I need help; I will go and ask teacher XY tomorrow (I will get help
from any science teacher who I can find its what they are paid for).
When I have done this I will tick it off my lists."
Return to Index
Where to get help ---------
|
Exercise books |
|
Text books |
|
Science teachers |
|
The Open Learning Centre |
|
The Internet |
|
These pages |
|
E-mail a science
teacher |
Return to Index
Cells ---
|
Nucleus//DNA |
|
Cytoplasm |
|
Cell membrane |
|
Cell wall |
|
Chloroplast//photosynthesis |
|
Vacuole |
|
Osmosis |
|
Plasmolysis |
|
Turgor//turgid |
|
Flaccid |
|
Osmosis |
one has:
nucleus, cytoplasm and cell membrane ONLY
an irregular shape
the other has:
nucleus, cytoplasm, cell membrane AND
a regular shape because it has a cell wall
chloroplasts so it can carry out
photosynthesis
Just think about your own body!
brain// sensory & motor neurons
bone// osteocytes = bone cells
muscle// muscle cells
liver// liver cells
blood// red blood cells & white blood
cells
Now find our about Prokaryotes
and Eukaryotes
OR have a look at my new pages on animal
cells and plant
cells
AND there is a page about osmosis
Return to Index
Digestion
What you might know already:
|
A balanced diet has - carbohydrate, protein,
fat, vitamins, mineral salts & fibre; |
|
Carbohydrate gives you energy; |
|
Protein is needed for growth & repair; |
|
Fats contain fat soluble vitamins; |
|
Vitamins are essential in SMALL quantities; |
|
Mineral salts are also essential, e.g.
Calcium, Iron & Iodine; |
|
Enzymes are needed to digest carbohydrate,
proteins and fats; |
|
Enzymes are substrate specific; |
|
Enzymes work better at body temperature; |
|
Enzymes only work at their optimum pH; |
|
Villi absorb glucose, amino-acids, fatty
acids, glycerol, vitamins and minerals; |
|
Villi have a large surface area. |
Now is the time to make sure that you know the
names of the enzymes which digest different kinds of food chemicals.
Return to Index
Photosynthesis
I am sure that you already know that:
|
Green plants contain a chemical called
chlorophyll; |
|
Chlorophyll is used in photosynthesis; |
|
Photosynthesis uses light energy to make
glucose; |
|
Photosynthesis takes place in the mesophyll
of a leaf; |
|
Photosynthesis also requires Carbon Dioxide
and water; |
|
Glucose can be used in respiration or stored
as starch; |
|
Iodine and starch turn black; |
|
Green light is not used in photosynthesis; |
|
Increasing the light intensity will make
photosynthesis faster. |
Please make sure that you have memorized the
word equation for photosynthesis, and the balanced chemical equation if
you are doing the higher papers. You can find these equations and an
explanation of how to balance
chemical equations here.
Return to Index
Respiration
You should know the difference between aerobic
and anaerobic respiration. You should also know word equations for
these. If you hope to get a grade A or B you should also be able to
write the balanced chemical equations for these reactions.
|
Aerobic respiration requires Oxygen. |
|
Anaerobic respiration does not require
Oxygen. |
|
Glucose + Oxygen = Carbon Dioxide + Water +
ENERGY |
|
Glucose = Carbon Dioxide + Ethanol + ENERGY
( in yeast). |
|
Glucose = Lactic Acid + ENERGY (you will get
cramp if you make too much). |
What is the purpose of respiration? NOT to get
rid of glucose! NOT to make Carbon Dioxide either! The purpose of
respiration is to release energy for other things like movement. So know
you know why we breathe.
Make a Jump to the Respiration
Page or have a look at the balanced
chemical equations for respiration.
Return to Index
Circulation
You should know about the composition and
functions of blood, the structure and functions of blood vessels
(arteries, veins, portal veins, and capillaries), and you should know
about the heart.
Go and have a look at my pages on
the heart and blood
now.
Return to Index
Ecology
Ecology is an interesting language. You may
already know the answers to lots of the ecology questions e.g.
|
What happens to the squirrels if the oak
trees don't produce any acorns? |
|
What happens to the greenfly if there are
more ladybirds? |
However if you do not use the correct language
you will not score so many marks. PLEASE, PLEASE, PLEASE use words like:
|
Population, |
|
Predation, |
|
Community, |
|
Ecosystem, |
|
Pollution, |
|
Grazing, |
|
Climatic factors, |
|
Biotic factors. |
SO don't say that all the squirrels will die if
there are no acorns: what will happen is the squirrel population will
decrease.
DON'T say that the ladybirds will eat all of
the greenfly. Think about it; more people in the town does not mean that
there will be no chips left in the chip shop! If there are more
ladybirds then the greenfly population will decrease in size.
More information is available for GCSE and
"A" Level students in my ecology
web. There is a page which provides you with
definitions and explanations of all the key words you need to know for
the ecology
section of your GCSE biology.
Return to Index
Muscles
Do you know what antagonistic muscles are?
Well this topic is really quite
straightforward. Muscles can contract and they can relax, but muscles
cannot stretch themselves or make themselves longer. What must happen
after a muscle has contracted is that it must BE stretched. This can
only happen when a muscle relaxes and another muscle pulls it longer. So
muscles always work in pairs. Nothing happens if BOTH muscles contract,
nothing happens if BOTH muscles relax, but when one muscle contracts and
the other muscle relaxes movement occurs. Such pairs of muscles are
called "antagonistic muscles" E.g. the biceps and the triceps.
When the biceps flexes (bends) the elbow the triceps is stretched, and
when the triceps extends (straightens) the elbow the biceps is
stretched.
PLEASE make sure that you can label a diagram
of the elbow or knee: bones & muscles.
Make a jump to my Muscles
Page.
Return to Index
Bones & joints
Another easy one! You should know that:
|
Bones are rigid tissues (they are living and
they do not bend); |
|
Bone supports your body, acts as a system of
levers, and protects vital organs. |
You should be able to label a diagram of a
synovial joint. My joints are held together by ligaments, they contain
synovial fluid which lubricates them, the synovial capsule holds the
fluid in, they contain cartilage which acts as a shock absorber. If you
play "kickball" you might have damaged your cartilage and had
some of it removed. I don't so I am still nice and bouncy and my bones
do not get damaged when I run and jump.
Tendons connect my muscles to my bones, so that
when I contract my muscles my bones are moved. Fortunately my tendons
and ligaments are inelastic, i.e they do NOT stretch.
Unfortunately I broke a ligament in one of my
knees so that knee is a bit wobbly.
Did you know that my knees and elbows work like
a hinge, they can bend and straighten; but my hips and shoulders works
like ball and sockets so they can move in more than one plane AND they
can swivel.
I expect that you body works just like mine
so why not take it into the exam with you, it might help to remind you
about the different parts and this is not really cheating!
Now take a jump to my muscles
page to see how the biceps and triceps flex
and extend your elbow joint.
E-mail requests for help to: -----------------
nigel@purchon.com----------
don't expect me to spell check.
Now have a go at the BBC's "BITESIZE"
pages (I wrote the text for twelve of them!):
How to Revise ------------
DO NOT:
|
panic |
|
just stare at the pages |
|
copy out your text book |
|
think you can do it all tomorrow |
|
expect someone else to do it for you |
What you should be doing:
|
keep calm |
|
do what you can |
|
use your time sensibly |
|
write three lists of topics which you
 |
know understand and have memorized |
|
understand and need to memorize |
|
need help with |
|
|
plan when you will do some memorizing |
|
get help from a science
teacher//parent//friend |
|
try some past papers |
This is the kind of thing you should end up with:
"I can label a diagram of the human
digestive system and get it all correct every time because I have
memorized it. I must memorize the names of the enzymes in the mouth and
stomach, I understand what they do but I didn't bother to memorize it for
homework last year. I will do this next Tuesday evening. I really don't
understand what happens to the food after it has been digested; I know I
need help; I will go and ask teacher XY tomorrow (I will get help from any
science teacher who I can find its what they are paid for). When I have
done this I will tick it off my lists."
Return to Index
Where to get help ---------
|
Exercise books |
|
Text books |
|
Science teachers |
|
The Open Learning Centre |
|
The Internet |
|
These pages |
|
E-mail a science
teacher |
Return to Index
Cells ---
|
Nucleus//DNA |
|
Cytoplasm |
|
Cell membrane |
|
Cell wall |
|
Chloroplast//photosynthesis |
|
Vacuole |
|
Osmosis |
|
Plasmolysis |
|
Turgor//turgid |
|
Flaccid |
|
Osmosis |
one has:
|
nucleus, cytoplasm and cell membrane ONLY |
|
an irregular shape |
the other has:
|
nucleus, cytoplasm, cell membrane AND |
|
a regular shape because it has a cell wall |
|
chloroplasts so it can carry out
photosynthesis |
Just think about your own body!
|
brain// sensory & motor neurons |
|
bone// osteocytes = bone cells |
|
muscle// muscle cells |
|
liver// liver cells |
|
blood// red blood cells & white blood
cells |
Now find our about Prokaryotes
and Eukaryotes
OR have a look at my new pages on animal
cells and plant
cells
AND there is a page about osmosis
Return to Index
Digestion
What you might know already:
|
A balanced diet has - carbohydrate, protein,
fat, vitamins, mineral salts & fibre; |
|
Carbohydrate gives you energy; |
|
Protein is needed for growth & repair; |
|
Fats contain fat soluble vitamins; |
|
Vitamins are essential in SMALL quantities; |
|
Mineral salts are also essential, e.g.
Calcium, Iron & Iodine; |
|
Enzymes are needed to digest carbohydrate,
proteins and fats; |
|
Enzymes are substrate specific; |
|
Enzymes work better at body temperature; |
|
Enzymes only work at
or near their optimum pH; |
|
Villi absorb glucose, amino-acids, fatty
acids, glycerol, vitamins and minerals; |
|
Villi have a large surface area. |
Now is the time to make sure that you know the
names of the enzymes which digest different kinds of food chemicals.
Return to Index
Photosynthesis
I am sure that you already know that:
|
Green plants contain a chemical called
chlorophyll; |
|
Chlorophyll is used in photosynthesis; |
|
Photosynthesis uses light energy to make
glucose; |
|
Photosynthesis takes place in the mesophyll of
a leaf; |
|
Photosynthesis also requires Carbon Dioxide
and water; |
|
Glucose can be used in respiration or stored
as starch; |
|
Iodine and starch turn black; |
|
Green light is not used in photosynthesis; |
|
Increasing the light intensity will make
photosynthesis faster. |
Please make sure that you have memorized the word
equation for photosynthesis, and the balanced chemical equation if you are
doing the higher papers. You can find these equations and an explanation
of how to balance chemical
equations here.
Return to Index
Respiration
You should know the difference between aerobic
and anaerobic respiration. You should also know word equations for these.
If you hope to get a grade A or B you should also be able to write the
balanced chemical equations for these reactions.
|
Aerobic respiration requires Oxygen. |
|
Anaerobic respiration does not require Oxygen. |
|
Glucose + Oxygen = Carbon Dioxide + Water +
ENERGY |
|
Glucose = Carbon Dioxide + Ethanol + ENERGY (
in yeast). |
|
Glucose = Lactic Acid + ENERGY (you will get
cramp if you make too much). |
What is the purpose of respiration? NOT to get
rid of glucose! NOT to make Carbon Dioxide either! The purpose of
respiration is to release energy for other things like movement. So know
you know why we breathe.
Make a Jump to the Respiration
Page or have a look at the balanced
chemical equations for respiration.
Return to Index
Circulation
You should know about the composition and
functions of blood, the structure and functions of blood vessels
(arteries, veins, portal veins, and capillaries), and you should know
about the heart.
Go and have a look at my pages on
the heart and blood
now.
Return to Index
Ecology
Ecology is an interesting language. You may
already know the answers to lots of the ecology questions e.g.
|
What happens to the squirrels if the oak trees
don't produce any acorns? |
|
What happens to the greenfly if there are more
ladybirds? |
However if you do not use the correct language
you will not score so many marks. PLEASE, PLEASE, PLEASE use words like:
|
Population, |
|
Predation, |
|
Community, |
|
Ecosystem, |
|
Pollution, |
|
Grazing, |
|
Climatic factors, |
|
Biotic factors. |
SO don't say that all the squirrels will die if
there are no acorns: what will happen is the squirrel population will
decrease.
DON'T say that the ladybirds will eat all of the
greenfly. Think about it; more people in the town does not mean that there
will be no chips left in the chip shop! If there are more ladybirds then
the greenfly population will decrease in size.
More information is available for GCSE and
"A" Level students in my ecology
web. There is a page which provides you with
definitions and explanations of all the key words you need to know for the
ecology
section of your GCSE biology.
Return to Index
Muscles
Do you know what antagonistic muscles are?
Well this topic is really quite straightforward.
Muscles can contract and they can relax, but muscles cannot stretch
themselves or make themselves longer. What must happen after a muscle has
contracted is that it must BE stretched. This can only happen when a
muscle relaxes and another muscle pulls it longer. So muscles always work
in pairs. Nothing happens if BOTH muscles contract, nothing happens if
BOTH muscles relax, but when one muscle contracts and the other muscle
relaxes movement occurs. Such pairs of muscles are called
"antagonistic muscles" E.g. the biceps and the triceps. When the
biceps flexes (bends) the elbow the triceps is stretched, and when the
triceps extends (straightens) the elbow the biceps is stretched.
PLEASE make sure that you can label a diagram of
the elbow or knee: bones & muscles.
Make a jump to my Muscles
Page.
Return to Index
Bones & joints
Another easy one! You should know that:
|
Bones are rigid tissues (they are living and
they do not bend); |
|
Bone supports your body, acts as a system of
levers, and protects vital organs. |
You should be able to label a diagram of a
synovial joint. My joints are held together by ligaments, they contain
synovial fluid which lubricates them, the synovial capsule holds the fluid
in, they contain cartilage which acts as a shock absorber. If you play
"kickball" you might have damaged your cartilage and had some of
it removed. I don't so I am still nice and bouncy and my bones do not get
damaged when I run and jump.
Tendons connect my muscles to my bones, so that
when I contract my muscles my bones are moved. Fortunately my tendons and
ligaments are inelastic, i.e they do NOT stretch.
Unfortunately I broke a ligament in one of my
knees so that knee is a bit wobbly.
Did you know that my knees and elbows work like a
hinge, they can bend and straighten; but my hips and shoulders works like
ball and sockets so they can move in more than one plane AND they can
swivel.
I expect that you body works just like mine so
why not take it into the exam with you, it might help to remind you
about the different parts and this is not really cheating!
Now take a jump to my muscles
page to see how the biceps and triceps flex and
extend your elbow joint.
E-mail requests for help to: -----------------
nigel@purchon.com----------
don't expect me to spell check.
Now have a go at the BBC's "BITESIZE"
pages (I wrote the text for twelve of them!):
|
