GCSE AQA Biology - Higher (Triple): Cell Biology

Differences Between Eukaryotic and Prokaryotic Cells

Eukaryotic Cells /

• Genetic material is contained in the nucleus

• Has membrane-bound organelles (e.g mitochondria, ribosomes)

• Generally larger (10–100 µm)

• Cell walls only in plant cells (made of cellulose) and fungal cells (mde of chitin)

• Reproduces by mitosis and meiosis

Prokaryotic Cells

• Genetic material is free floating in the cytoplasm in chromosome loop / plasmids

• Does not have membrane-bound organelles

• Generally smaller (0.1–5 µm)

• Cell wall made of peptidoglycan

• Reproduces by binary fission

Animal Cell Diagram

* Add image of labelled animal cell

Plant Cell Diagram

* Add imge of labelled plant cell

Fungal Cell Diagram

* Add imge of labelled fungal cell

Bacterial Cell Diagram

* Add imge of labelled bacterial cell

Protists

• group of exclusion

• examples: malaria parasite, amoeba

Function of the Nucleus

Function of the Cytoplasm

Function of the Cell Membrane

Function of the Mitochondria

Function of the Ribosomes

Function of the Chloroplasts

Fucntion of the Vaccuole

Function of the Cell Wall

Specialisation of Spem Cells

Specialised to carry male DNA to the egg cell for fertilisation

• Streamlined head and long tail: aids mobility

• Many mitochondria: supply energy for tail movement

• Digestive enzymes in the acrosome: breaks down the outer layers of the membrane and egg

• Contins nucleus with half the genetic material: allows the sperm cell to fuse with an egg cell to restore the normal chromosome number

Specialisation of Nerve Cells

Specialised to transmit electrical signals quickly from one place in the body to another

• Long axon: allows for impulses to be carried over long distances

• Dendrites: allows branched connections to form with other nerve cells

• Nerve endings have mitochondria: supply energy to make neurotransmitters (allow impulses to be be passed from one cell to another)

• Mylein sheath: insulates the nerve cell, increasing the speed of transmission

Specialisation of Muscle Cells

Specialised to contract (striated muscle) or squeeze (smooth muscle) therefore causing no movement

• Protein (myosin and actin) slide over eachother: causes muscles to contract

• Lots of mitochondria: to to provide energy from respiration to contract

• Can store glycogen: used in respiration by mitochondria

Specialisation of Root Hair Cells

Specialised to take up water by osmosis and mineral ions by active transport from the soil

• Large SA due to root hairs: increases absorption efficiency as more water can move in

• Permanent Vaccuole: affects the speed of movement of water from the soil to the cell

• Lots of mitochondira: to provide energy for active transport

Specialisation of Xylem Cells

Specialised to transport water and mineral ions up the plant from the roots to the shoots

• Lignin (a chemical causing the cells to die): makes the xylem cells hollow and to be joined to form a continuous tube so water and mineral ions can move through

  • The hollow tubes of xylem allow for efficient water movement as they provide strength and support, allowing the xylem to withstand internal pressure