Biology paper 1:
Cell biology
Animal and plant cells are eukaryotic.
Both contain cell membrane, cyptoplasm and a nucleus (contains dna)
Bacterial cells are prokaryotic. They are much smaller than eukaryotic cells and contain a cell wall,
cell membrane, cyptoplasm and singular strand of dna.
These structures are called organelles- they are within a cell and hold different functions.
Converting units:
Centi- x0.01
Milli – x0.001 (3)
Micro- x0.000001 (5)
Nano- x0.000000001 (8)
Animals and plants have sub cellular structures inside cells that all have a specific function:
Both plant/animal structures:
Nucleus- contains dna used to build new cells.
Cyptoplasm- liquid substance where chemical reactions occur. Contains enzymes.
Cell membrane- controls what leaves and enters the cell.
Mitochondria- where aerobic respiration occurs. Provides energy for the cell.
Ribosomes- where protien synthesis occurs.
Only plant cells
Chloroplasts- where photosynthesis occurs providing food to the plant. Contains chlorophyll which
absorbs light for photosynthesis
Permanent vacuole- contains cell sap. Found in the cyptoplasm of a plant. Ensures the rigidity of the
cell.
Cell wall- made from celluose. Provides strength to the cell.
Bacterial cells
Bacterial cells are prokaryotic.
They contain a cyptoplasm, cell membrane & cell wall.
They also contain:
singular circular strand of dna – as they have no nucleus this is in the cytoplasm.
plasmids- small rings of dna.
, Cell specialisation:
Cells specialise by undergoing cell differentiation. This involves the cell gaining new sub-cellular
structures in order to be better suited to its rule. The stem cells either differentiate early on or have
the ability to differentiate throughout their life.
Stem cell types:
A stem cell is an undifferentiated cell which can undergo division to produce more cells that can
differentiate to have different functions.
Embryonic stem cells:
1. Form when an egg and sperm cell fuse to from a zygote
2. They can differentiate into any type of cell in the body
3. Scientist can clone these cells and direct them into differentiating into almost any cell in the
body.
4. Could be used to replace insulin producing cells(diabetes), create neural cells (alzheimer’s)
or nerve cells (paralysis)
Adult stem cells
1. If found in bone marrow, they can form many types of cells including blood cells.
Meristems in plants
1. Found in roots and shoot tips
2. They can differentiate into any plant type and have the ability to differentiate throughout
the life of the plant.
3. They can be used to make clones of the plant (necessary if the plant has certain desirabe
features or for research or to save a rare plant from extinction.
Therapeutic cloning:
Involves in an embryo being produced with the same genes as the patient.
1. The embryo produced could be then harvested to obtain the embryonic stem cells
2. These can be grown into any cells the patient needed
3. Cannot be rejected because they have the same genetic make up as the patient.
Specialised cells in plants/animals:
Sperm cells - specialised to carry the male dna to the egg. Has a streamlined head and long tail to aid
swimming. Many mitochondria to supply energy to allow the cell to move. The acrosome has
digestive enzymes to break down the layers of membrane in the egg.
Nerve cells- specialised to transmit electrical signals quickly. Has a long azon to enable the impulses
to be carried along long distances. Has a lot of dendrites (extensions from the cell body) enabling
branched connections with other nerve cells?
Muscle cells- specialised to contract quickly to move bones and cause movement. They have special
protiens (myosin and actin) slide over each other to contract. Lots of mitochondria to provide energy
from respiration for contraction. They store glycogen used in respiration by mitochondria.
Cell biology
Animal and plant cells are eukaryotic.
Both contain cell membrane, cyptoplasm and a nucleus (contains dna)
Bacterial cells are prokaryotic. They are much smaller than eukaryotic cells and contain a cell wall,
cell membrane, cyptoplasm and singular strand of dna.
These structures are called organelles- they are within a cell and hold different functions.
Converting units:
Centi- x0.01
Milli – x0.001 (3)
Micro- x0.000001 (5)
Nano- x0.000000001 (8)
Animals and plants have sub cellular structures inside cells that all have a specific function:
Both plant/animal structures:
Nucleus- contains dna used to build new cells.
Cyptoplasm- liquid substance where chemical reactions occur. Contains enzymes.
Cell membrane- controls what leaves and enters the cell.
Mitochondria- where aerobic respiration occurs. Provides energy for the cell.
Ribosomes- where protien synthesis occurs.
Only plant cells
Chloroplasts- where photosynthesis occurs providing food to the plant. Contains chlorophyll which
absorbs light for photosynthesis
Permanent vacuole- contains cell sap. Found in the cyptoplasm of a plant. Ensures the rigidity of the
cell.
Cell wall- made from celluose. Provides strength to the cell.
Bacterial cells
Bacterial cells are prokaryotic.
They contain a cyptoplasm, cell membrane & cell wall.
They also contain:
singular circular strand of dna – as they have no nucleus this is in the cytoplasm.
plasmids- small rings of dna.
, Cell specialisation:
Cells specialise by undergoing cell differentiation. This involves the cell gaining new sub-cellular
structures in order to be better suited to its rule. The stem cells either differentiate early on or have
the ability to differentiate throughout their life.
Stem cell types:
A stem cell is an undifferentiated cell which can undergo division to produce more cells that can
differentiate to have different functions.
Embryonic stem cells:
1. Form when an egg and sperm cell fuse to from a zygote
2. They can differentiate into any type of cell in the body
3. Scientist can clone these cells and direct them into differentiating into almost any cell in the
body.
4. Could be used to replace insulin producing cells(diabetes), create neural cells (alzheimer’s)
or nerve cells (paralysis)
Adult stem cells
1. If found in bone marrow, they can form many types of cells including blood cells.
Meristems in plants
1. Found in roots and shoot tips
2. They can differentiate into any plant type and have the ability to differentiate throughout
the life of the plant.
3. They can be used to make clones of the plant (necessary if the plant has certain desirabe
features or for research or to save a rare plant from extinction.
Therapeutic cloning:
Involves in an embryo being produced with the same genes as the patient.
1. The embryo produced could be then harvested to obtain the embryonic stem cells
2. These can be grown into any cells the patient needed
3. Cannot be rejected because they have the same genetic make up as the patient.
Specialised cells in plants/animals:
Sperm cells - specialised to carry the male dna to the egg. Has a streamlined head and long tail to aid
swimming. Many mitochondria to supply energy to allow the cell to move. The acrosome has
digestive enzymes to break down the layers of membrane in the egg.
Nerve cells- specialised to transmit electrical signals quickly. Has a long azon to enable the impulses
to be carried along long distances. Has a lot of dendrites (extensions from the cell body) enabling
branched connections with other nerve cells?
Muscle cells- specialised to contract quickly to move bones and cause movement. They have special
protiens (myosin and actin) slide over each other to contract. Lots of mitochondria to provide energy
from respiration for contraction. They store glycogen used in respiration by mitochondria.
