Eukaryotes and prokaryotes
Monday, March 25, 2024 5:11 PM
A eukaryotic cell is a type of cell which has a nucleus:
• Animal cells
• Plant cells
• Fungi
A prokaryotic cell is a type of cell which does not have a nucleus, and
the DNA is free in the cytoplasm:
• Bacteria
Summary:
Eukaryotic Prokaryotic
Cell size 5 μm – 100 μm 0.2 μm – 2.0 μm
Cell contents Cytoplasm, cell membrane, nucleus, mitochondria, Cytoplasm, ribosomes. NO nucleus, mitochondria, or
ribosomes chloroplasts
Genetic material In a nucleus Free in the cytoplasm, sometimes in rings called plasmids
Type of cell Mitosis Binary Fission
division
Outer layer Cell membrane (Cell wall in plants + fungi) Cell membrane + Cell wall
Cell Biology Page 1
,Animal & Plant cells
Monday, March 25, 2024 5:20 PM
All animals and plants are made up of cells.
Function
Cytoplasm A jelly-like substance which contains dissolved
nutrients and organelles. It is where many of the
chemical reactions happen
Cell Controls the movement of substances in and out the
membrane cell
Nucleus Contains DNA, which controls the cells activities
Mitochondria Contain enzymes for respiration
Ribosomes Tiny structures where protein synthesis occurs
Chloroplasts Contain a green pigment called chlorophyll, which
absorbs light energy needed for photosynthesis
Cell wall Made from cellulose which strengthens and
supports the plant
Permanent Filled with cell sap to keep the cell turgid
vacuole
Animal cells & their structure:
Each type of cell is specialised for a particular role:
1. Sperm cell: Sperm cells are mobile – their tail helps propel them forward in search of an egg to fertilise
• The acrosome head contains digestive enzymes which can break
down the outer layer of an egg cell
• The mid piece is packed with mitochondria ready to release
energy so it can respire
• The tail allows the sperm cell to propel itself forward and swim
• The head contains a nucleus which has half the genetic material
needed for fertilisation
2. Nerve cell: Nerve cells (neurones) have a characteristically elongated structure which allows them to coordinate information from
the brain and spinal cord with the rest of the body
• Covered in a fatty sheath which insulated the nerve cell and
speeds up nerve impulses
• Dendrites allow the cell to communicate with other cells,
muscles, and glands
• Has a cell body where most of the cell structures are located
3. Muscle cell: Muscle cells contain layers of fibres which allow them to contract.
Cell Biology Page 2
, • Protein filaments allow muscles to slide over each other causing
muscle contractions
• Lots of mitochondria for respiration
• Skeletal muscle cells merge so muscle fibres contract in unison
Plant cells and their structure:
1. Root hair cell: The root hair is an extension of the cytoplasm, increasing the surface area of the cell in contact with the soil to
maximise absorption of water and minerals
• Root hair extends out to increase the surface area so more
water and ions can be absorbed
• Thinner walls so water can move in easily
• Mitochondria for active transport
• Permanent vacuole contains concentrated cell sap to maintain a
large water potential gradient for osmosis
2. Xylem cell: Xylem cells lose their top and bottom walls to form a continuous tube through which water moves from the roots to the
leaves.
• No top and bottom to form a continuous, hollow cell so
water can be drawn upwards (transpiration)
• Cells are dead to allow free passage of water
• Walls thickened with lignin to strengthen the tube to
support the plant
1. Phloem cell: Phloem cells form tubes similar to xylem vessels, except the cells still retain some subcellular structures and are
therefore living
• Have companion cells which provide energy required to transport
substances
• Few subcellular structures to aid the flow
Cell Biology Page 3
, • Have companion cells which provide energy required to transport
substances
• Few subcellular structures to aid the flow
• Cells joined end to end with sieve plates to aid the movement of
sugars and amino acids
Cell Biology Page 4
Monday, March 25, 2024 5:11 PM
A eukaryotic cell is a type of cell which has a nucleus:
• Animal cells
• Plant cells
• Fungi
A prokaryotic cell is a type of cell which does not have a nucleus, and
the DNA is free in the cytoplasm:
• Bacteria
Summary:
Eukaryotic Prokaryotic
Cell size 5 μm – 100 μm 0.2 μm – 2.0 μm
Cell contents Cytoplasm, cell membrane, nucleus, mitochondria, Cytoplasm, ribosomes. NO nucleus, mitochondria, or
ribosomes chloroplasts
Genetic material In a nucleus Free in the cytoplasm, sometimes in rings called plasmids
Type of cell Mitosis Binary Fission
division
Outer layer Cell membrane (Cell wall in plants + fungi) Cell membrane + Cell wall
Cell Biology Page 1
,Animal & Plant cells
Monday, March 25, 2024 5:20 PM
All animals and plants are made up of cells.
Function
Cytoplasm A jelly-like substance which contains dissolved
nutrients and organelles. It is where many of the
chemical reactions happen
Cell Controls the movement of substances in and out the
membrane cell
Nucleus Contains DNA, which controls the cells activities
Mitochondria Contain enzymes for respiration
Ribosomes Tiny structures where protein synthesis occurs
Chloroplasts Contain a green pigment called chlorophyll, which
absorbs light energy needed for photosynthesis
Cell wall Made from cellulose which strengthens and
supports the plant
Permanent Filled with cell sap to keep the cell turgid
vacuole
Animal cells & their structure:
Each type of cell is specialised for a particular role:
1. Sperm cell: Sperm cells are mobile – their tail helps propel them forward in search of an egg to fertilise
• The acrosome head contains digestive enzymes which can break
down the outer layer of an egg cell
• The mid piece is packed with mitochondria ready to release
energy so it can respire
• The tail allows the sperm cell to propel itself forward and swim
• The head contains a nucleus which has half the genetic material
needed for fertilisation
2. Nerve cell: Nerve cells (neurones) have a characteristically elongated structure which allows them to coordinate information from
the brain and spinal cord with the rest of the body
• Covered in a fatty sheath which insulated the nerve cell and
speeds up nerve impulses
• Dendrites allow the cell to communicate with other cells,
muscles, and glands
• Has a cell body where most of the cell structures are located
3. Muscle cell: Muscle cells contain layers of fibres which allow them to contract.
Cell Biology Page 2
, • Protein filaments allow muscles to slide over each other causing
muscle contractions
• Lots of mitochondria for respiration
• Skeletal muscle cells merge so muscle fibres contract in unison
Plant cells and their structure:
1. Root hair cell: The root hair is an extension of the cytoplasm, increasing the surface area of the cell in contact with the soil to
maximise absorption of water and minerals
• Root hair extends out to increase the surface area so more
water and ions can be absorbed
• Thinner walls so water can move in easily
• Mitochondria for active transport
• Permanent vacuole contains concentrated cell sap to maintain a
large water potential gradient for osmosis
2. Xylem cell: Xylem cells lose their top and bottom walls to form a continuous tube through which water moves from the roots to the
leaves.
• No top and bottom to form a continuous, hollow cell so
water can be drawn upwards (transpiration)
• Cells are dead to allow free passage of water
• Walls thickened with lignin to strengthen the tube to
support the plant
1. Phloem cell: Phloem cells form tubes similar to xylem vessels, except the cells still retain some subcellular structures and are
therefore living
• Have companion cells which provide energy required to transport
substances
• Few subcellular structures to aid the flow
Cell Biology Page 3
, • Have companion cells which provide energy required to transport
substances
• Few subcellular structures to aid the flow
• Cells joined end to end with sieve plates to aid the movement of
sugars and amino acids
Cell Biology Page 4
