B1 - Cell Structure And Organisation Flashcards
E. Magnification
Magnification= image size / size of real object
Function of cytoplasm?
Site of chemical reactions
Function of ribosomes?
Site of protein synthesis
Function of mitochondria?
Site of aerobic respiration
Function of cell membrane?
Controls the movement of substances in and out of the cell.
Function of chloroplast?
Absorbs sunlight to make glucose from photosynthesis
Specifically: contains green pigment chlorophyll which absorbs the light
What are plasmids?
Small rings of DNA that code for specific features such as antibiotic resistances
Bacteria are….
Prokaryotic cells
Examples of specialised cells?
Nerve cells, muscle cells, sperm cells, red blood cells, ciliated epithelial cells, root hair cells etc etc
What is the function and adaptations of a nerve cell? (4)
Function: To provide a rapid communication system between different parts of the body
Adaptations:
1) Lots of dendrites that make connections to other cells
2) Axons that carry the impulse from one place to another
3) Synapses are adapted to pass the impulse to another cell or between a nerve cell and a muscle cell (using special transmitter chemicals)
4) Lots of mitochondia that are the site of respiration and releases energy to send impulses
What is the function and adaptations of a muscle cell? (3)
Function: To contract and relax to allow movement (of the bones of the skeleton)
Adaptations:
1) Contain proteins that slide over each other and make the fibres contract
2) Contain many mitochondria to release the energy needed for chemical reactions to take place via respiration
3) Store glycogen, which can be broken down and used in cellular respiration by the mitochondria to provide energy needed for the fibres to contract.
What is the function and adaptations of a sperm cell? (4)
4
Function:
Contains genetic information from the male parent and has to reach the egg to fertilise it
Adaptations:
1) Long tail helps it to move
2) Middle section is full of mitochondria, which provide energy for the tail to move
3) Large nucleus contains genetic information to be passed on
4) Acrosome stores digestive enzymes to break down the outer layers of the egg
Specialised plant cells?
Root hair cells, photosynthetic cells, xylem cells and phloem cells
How are root hair cells specialised? (3)
Function: To help plants take up water and mineral ions more efficiently
Adaptations
1) Extensions giving an increased surface area allowing for more space for water to move into the cell
2) Permanent vacuole that speeds up movement of water by osmosis from the soil across the root hair cell
3) Many mitochondria to transfer energy needed for active transport of mineral ions into the cells
What is the function and adaptations of a photosynthetic cell?
Function: Absorb sunlight to produce food through photosynthesis
Adaptations:
1) Contain specialised chloroplasts containing chlorophyll which absorbs the sunlight needed for photosynthesis
2) Usually positioned in continuous layers in the leaves and outer layers of the stem so they absorb as much light as possible
3) Large perm vacuole that keeps the cell rigid as a result of osmosis when lots of these rigid cells are arranged together, they help support the stem.
What is the function of xylem cells and how are these adapted?
Function: To carry water and mineral ions fromm the roots to the high leaves and shoots
Adaptations:
1) Forms dead long hollow tubes to allow water and mineral ions to move easily from one end of the plant to another
2) Spirals and rings of lignin in cell walls helping the cell to withstand the pressure of water moving up the plant, making the plant very strong
What is the function and adaptations of a phloem cell?
Function: To carry sugars made by photosynthesis aronud the plant (via translocation)
Adaptations:
1) Cell walls between the cells break down to form special sieve plates. Allow water carrying dissolved food to move freely
2) Supported by companion cells containing mitochondria which transfer energy needed to move sugars up and down the plant for active transport
3) Few organelles to maximise the flow rate of food
D. Diffusion
The net movement of particles from an area of high conentration to an area of low concentration down a concentration gradient
Examples of diffusion IRL?
1) Glucose mvoing from the small intenstine to the blood
2) Oxygen moving into cells
3) Carbon dioxide and water vapour moving in to the stoma
What effects the rate of diffusion?
↑ ↓
1) Humidity (↓ rate)
2) ↑ Wind (↑ rate)
3) ↑ Surface area (↑ rate)
4) Steeper conc gradient (↑ rate)
5) ↓ Diffusion distance (↑ rate)
6) ↑ Temperature (↑ rate)
How do substances such as urea and glucose and gases such as oxygen and carbon dioxide move out and into cells?
Diffusion
D. Osmosis?
The net movement of water particles from an area of high water concentration to an area of low water concentration down a water concentration gradient across a partially permeable membrane
D. Isotonic?
The concentration of the solution is the same inside and outside the cell
D. Hypertonic?
Conc of solutes in the solution is higher than the internal conc (so solution is hypertonic to cell)
