B2- Cells, Tissues and Organs Flashcards
Define diffusion.
The movement of gas or liquid molecules from a region of high concentration ➡️low concentration.
Give three examples of diffusion.
- Diffusion of oxygen into cells from bloodstream/ Diffusion of CO2 out of cells as a product of respiration.
- Neurotransmitters diffuse across a synapse.
- Products of digestion diffuse from small intestine into blood.
Describe where DNA is found in a human cell (2 marks).
The DNA is in the chromosomes, in the nucleus of a human cell.
How does the structure of ciliates epithelial cells link to their function?
Tiny little hairs protruding from the surface pushes the mucus into the throat so it can be coughed up.
Bacteria contain…
- A cell membrane and cell wall.
- Cytoplasm and ribosomes.
- NO NUCLEUS so genetic material is in the cytoplasm.
Animals tissues include…
Muscle tissue- can contract to bring about movement.
Glandular tissue- produce substances such as enzymes and hormones.
Epithelial tissue- covers some parts of the body.
Most animal cells contain…
- A nucleus.
- A cell membrane.
- Cytoplasm.
- Mitochondria.
- Ribosomes.
Define xylem tissue in plants.
Transports water and salutes from roots to leaves.
How does the structure of sperm cells link to its function?
Streamlined- reduces resistance.
Tail- tails propels them forward.
Mitochondria- more respiration = more energy.
What is the function of chloroplasts?
Chloroplasts contains chlorophyll which absorbs light for photosynthesis.
Define a tissue.
A tissue is a group of specialised cells that have a similar structure and function.
What is the function of a vacuole?
The vacuole contains cell sap to keep the cell enlarged and turgid with water.
What is the function of a cell wall?
The cell wall supports/strengthens the cell and stops it bursting.
The stomach is an organ made out of:
- Muscular tissue to churn food and other contents.
- Glandular tissue to produce digestive juices like acids and enzymes.
- Epithelial tissue to cover the inner and outer surfaces of the stomach.
The digestive system is a muscular tube which includes:
Pancreas and salivary glands- to produce digestive juices.
Liver- to produce bile which emulsified fats and neutralises stomach acid.
Small intestine- to digest and absorb soluble food.
Large intestine- to absorb water from undisgested food, producing faeces.
What is the function of cytoplasm?
Cytoplasm is where most chemical reactions take place in a cell.
How does the structure of root hair cells link to their function?
Root hair cells have a larger surface area so they can absorb water and minerals efficiently.
Plant cells contain everything in an animal cell, plus…
- A cell wall.
- Chloroplasts.
- A vacuole.
What is the function of mitochondria?
Mitochondria is where energy is released during respiration.
Define phloem tissue in plants.
Transports food from leaves to the rest of the plant.
Describe the structure of the leaf and the functions of the tissues in the leaf (6 marks)
Waxy cuticle➡️Reduces water loss.
No chloroplasts in epidermis➡️Allows light to penetrate.
Stomata/Guard cells➡️Allow CO2 in and O2 out.
Palisade mesophyll➡️Many chloroplasts traps light.
Spongy mesophyll➡️Air spaces for rapid movement of gases.
How does the structure of red blood cells link to its function?
No nucleus- more room for haemoglobin.
Biconcave- larger surface area so it can carry more oxygen.
Small and flexible- easier to squeeze through capillaries.
What factors affect the rate of diffusion and how?
Temperature- Higher temperature➡️Higher rate of diffusion.
Concentration- Higher concentration➡️Higher rate of diffusion.
Define organ.
An organ contains different tissues, working together to carry out a particular function.
What is the function of ribosomes?
Ribosomes are where proteins is made.
Yeast is a single-celled organism which contains…
- Nucleus.
- Cell wall.
- Cell membrane.
- Cytoplasm.
- Mitochondria.
What is the function of a cell membrane?
The cell membrane controls the movement of materials in and out of the cell.
What is the function of a nucleus?
A nucleus contains genetic material and controls the cell’s activities.
