GCSE Biology - B4 The Processes of Life - Revision Notes

My revision notes on GCSE Biology - OCR 21st Century Science - C6 The Processes of life. Hope they help!

HideShow resource information
  • Created by: Rhys B-M
  • Created on: 25-04-12 19:45
Preview of GCSE Biology - B4 The Processes of Life - Revision Notes

First 190 words of the document:

B4 - The Processes of Life - Revision Notes
Part of Cell Animal Plant Bacteria Yeast Explanation
Nucleus Contains DNA, the instructions for
making proteins, (e.g. the enzymes
used in the chemical reactions of
respiration and photosynthesis).
Cytoplasm Gel-like substance where proteins
like enzymes are found. Some
enzyme controlled reactions happen
here, (e.g the reactions of anaerobic
respiration).
Cell Membrane Holds the cell together and controls
what goes in and out of the cell. It
lets water and gases pass through
freely but acts as a barrier to other
chemicals.
Mitochondria Where the enzymes needed for the
reactions of aerobic respiration are
found, and where the reactions take
place.
Cell Wall Supports and strengthens the cell,
made of cellulose.
Chloroplasts Where the reactions of
photosynthesis take place. They
contain a green substance called
chlorophyll and the enzymes needed
for photosynthesis.
Vacuole Contains cell sap, a weak solution of
sugar and salts.
Yeast Cell Bacteria Cell
Cytoplasm

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

Bacteria cells are a bit different to plant/animal/yeast cells. They don't have a nucleus, instead they
have a circular molecule of DNA which floats in the cytoplasm. Also they don't have mitochondria,
but they can still respire aerobically.
Living things have thousands of chemical reactions happening inside of them all the time, these
reactions need to be carefully controlled to get the right amounts of substances. Living things
produce enzymes.…read more

Page 3

Preview of page 3

Here's a taster:

Active Transport ­ This process uses energy to move substances in and out of cells.
Synthesis Of Large Molecules ­ Lots of large molecules (polymers) are made by joining smalled
molecules together, this requires energy. For example, glucose is joined together to make things like
starch and cellulose in plant cells. In plant cells, animal cells and microorganisms, glucose and
nitrogen are joined together to make amino acids. The amino acids are joined together to make
proteins.…read more

Page 4

Preview of page 4

Here's a taster:

Sugar like glucose are carbohydrates.
Bread ­ Bread is made using yeast, the yeast ferment the carbohydrates in the flour and release
carbon dioxide which causes the bread to ride.
Alcohol ­ Yeast ferment sugar to form alcohol (ethanol). The sugar used in alcohol production comes
from things like grapes (wine) and barley (beer).
PHOTOSYNTHESIS IS A SERIES OF CHEMICAL REACTIONS THAT USES ENERGY FROM SUNLIGHT TO
PRODUCE FOOD.
The `food' it produces is glucose.
Photosynthesis happens in the cells of green plants (e.g.…read more

Page 5

Preview of page 5

Here's a taster:

Not enough light slows down the rate of photosynthesis.
Light provides the energy needed for photosynthesis, as the light level is raised, the rate of
photosynthesis increases steadily ­ but only up to a point. After that, it won't make a difference
because then either temperature or CO level will be the limiting factor.
Too little carbon dioxide also slows down the rate of photosynthesis.…read more

Page 6

Preview of page 6

Here's a taster:

A partially permeable membrane is one that only allows certain substances to diffuse through it. E.g.
it may only allow small molecules like water to pass through and not larger molecules like sucrose.
Plants take in water through osmosis, there's usually a higher concentration of water in the soil than
there is inside the plant, water is drawn up into the root by osmosis.…read more

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all resources »