B1 - Cell Structure and Transport Flashcards
- What types of microscopes are there? (2 marks)
a. Light Microscope b. Electron Microscope
- Why are electron microscopes better? (2 marks)
a. They have a much higher magnification and resolving power b. So you can see organelles inside cells a lot clearer and in more detail
- How do you calculate the magnification of an image? (1 mark)
a. Magnification = size of image/size of real object
- Label the structures of an animal cell (6 marks)

7) What are the key features of a bacterial cell? (5 marks)
a. Cytoplasm b. Cell Membrane c. Cell wall d. Genes are not in a nucleus e. DNA is in loops called plasmids
- Label the structures of a plant cell (6 marks)
- Label the structures of a plant cell (6 marks)

- What are the key organelles common to both animal and plant cells and their functions? (6 marks)
- Nucleus - Stores genetic information, Controls the activity of the cell
- Cytoplasm - Where most chemical reactions take place
- Cell Membrane - Controls what substances go in and out of the cell
- Mitochondria - The site of respiration, where energy is released
- Ribosomes - Where protein synthesis takes place
- What are they key features of yeast cells? (5 marks)
- Cytoplasm
- Cell Membrane
- Cell wall
- Genes are not in a nucleus
- DNA is in loops called plasmids
- What are specialised cells? (1 mark)
- Cells that carry out a particular function
- How are sperm cells specialised to carry out their function? (3 marks)
- Tail- to help it move/swim
- Lots of mitochondria- release energy for movement
- Head contains enzymes- to digest/break down outside of egg
- How are muscle cells specialised to carry out their function? (1 mark)
- Lots of mitochondria- release energy for movement
- How are root hair cells (in plants) specialised to carry out their function? (2 marks)
- Large surface area- to speed up osmosis
- Thin wall- to absorb water more quickly
- What is cell differentiation? (1 mark)
- When a cell forms different types of cells to carry out a particular function and becomes a specialised cell
- How does cell differentiation occur in animals? (2 marks)
- Differentiation occurs in animals at an early stage
- It occurs to repair and replace old cells
How does cell differentiation occur in plants? (1 mark)
Plants cells can differentiate throughout life
- How can dissolved substances move into and out of cells? (1 mark)
- Diffusion
- What is diffusion? (2 marks)
- The movement of particles (gas or substance in solution) from an area of high concentration to an area of low concentration
- Down a concentration gradient
Why is oxygen required to diffuse into cells? (1mark)
- Needed for respiration
Give examples of where diffusion occurs in the body ( 3 marks)
- Oxygen diffuses into cells during gas exchange
- Carbon dioxide diffuses out of cells during gas exchange
- Urea (waste product) diffuses from cells into the blood plasma for excretion in the kidney
- Give examples of where diffusion
- Carbon dioxide diffuses into plants for photosynthesis
- Oxygen diffuses from the plant back into the air
tate three factors which affect the rate of diffusion (3 marks)
- The difference in concentrations (concentration gradients)
- Temperature
- Surface area of the membrane
- In multicellular organisms, how is exchange of materials efficient? (2marks)
- Surfaces and organ systems have a smaller surface area to volume ratio
- Therefore sufficient molecules can be transported in and out of cells
- How can the effectiveness of an exchange surface be increased? (4 marks)
- Having a large surface area
- Thin membrane to provide a short diffusion path
- In animals, an efficient blood supply
- In animals, being ventilated (for gaseous exchange)
What is Osmosis? (1 mark)
- The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
- What is osmosis? ( 4marks)
- Movement of water
- Through a partially permeable membrane
- From a dilute to a concentrated solution
- It’s passive
- How is a plant root adapted for absorbing water? (5 marks)
- There are many hairs that are one cell thick
- Which gives a large surface area
- With a short diffusion pathway
- So there is more diffusion or osmosis
- Into the root
- Explain why roots have to use two methods for absorbing water and ions in their roots (4 marks)
- Solution is dilute in soil
- Water moves from the dilute solution into the more concentrated cell (osmosis)
- Concentration of ions in soil is less than in the cell
- Ions move against the concentration gradient (active transport)
- What is Active Transport? (2 marks)
- This moves substances from a more dilute solution to a more concentrated soltuon (against a concentration gradient)
- It requires energy
- Where does active transport take place in plants? (2 marks)
- Active transport allows mineral ions to be absorbed into plant root hair from dilute solutions in the soil
- Plants require ions for healthy growth
- Where does active transport take place in animals? ( 2marks)
- It allows sugar molecules to be absorbed from lower concentrations in the gut to the blood which has a higher sugar concentration
- Sugar molecules are used for cell respiration
- What are the features of an exchange surface that allow efficient exchange (4 marks)
- Large surface area
- Thin to provide a short diffusion pathway
- Efficient blood supply (in animals only)
- Well ventilated (in animals for gas exchange)
- Where does gas exchange take place in the lungs? (1 mark)
- Alveoli
- What structure increases the surface area of the lungs? (1 mark)
- Alveoli
What structure increases the surface area of the small intestine? (1 mark)
- Villi
How is a plant root adapted for absorbing water? (5 marks)
- There are many hairs that are one cell thick
- Which gives a large surface area
- With a short diffusion pathway
- So there is more diffusion or osmosis
- Into the root
- What are the key organelles found only in plant cells and what are their functions? (4 marks)
Cellulose cell wall - Strengthens the cell
Chloroplast - Contains chlorophyll (green pigment), Absorbs light energy to make food
Permanent vacuole - Contains cell sap
- Why do ribosomes rely on mitochondria to function? (3 marks)
- Mitochondria carry out respiration
- So release energy
- This energy is needed so the ribosomes can make proteins