Cells Flashcards
Cells structure
Living organisms are made of cells
How are Animal cells like
Multicellular
Cells containing nucleons with distinct membrane
No cellulose walls
No chloroplasts
Feed organic substances made by living things
Able to move from place to place, have nervous coordination
How are plant cells
Multicellular
Contain nucleus with distinct membrane
Contain chloroplasts (to carry out photosynthesis)feed by photosynthesis
Store carbohydrates as starch or sucrose
No nervous coordination
Nucleus function (both animal and plant)
Contain genetic material (dna) which controls cell activities
Cytoplasm (both animal and plant)
Gel like substance composed of water and dissolved solutes
Support internal cell structures
Site of many chemical reactions including anaerobic respiration
Cell membrane (both animal and plant)
Holds cell together, separating inside from outside
Controls which substance can enter and leave the cell
Cell membrane (both animal and plant)
Holds cell together, separating inside from outside
Controls which substance can enter and leave the cell
Ribosomes (both animal and plant)
Found in the cytoplasm
site of protein synthesis
Mitochondria (both animal and plant)
Site of most of the reactions involving aerobic respiration, where energy is released to fuel cellular processes
Cell with high rates of metabolism( carrying many different cell reactions) significantly have higher numbers of mitochondria than cells with fewer reactions taking place
Cell wall (only plant)
Made of cellulose (polymer of glucose)
Chloroplasts
Containing green chlorophyll pigments (to absorb light energy) and the enzymes needed for photosynthesis
Permanent vacuole
Contains SAP: solution of sugars and salts dissolved in water
Used for storage of certain materials
Also helps support cells shape
Magnification equation
Magnification = image size / actual size
Movement in and out of cells
Diffusion
Te movement of particles form a region of their higher concentration to a region of their lower concentration down a concentration gradient, as a result of random movement
Movement in and out of cells
Diffusion
Te movement of particles form a region of their higher concentration to a region of their lower concentration down a concentration gradient, as a result of random movement
Factors influencing diffusion
Surface area to volume ratio
Distance
Temperature
Concentration gradient
How does Diffusion occur across cell membrane
Substance move in and out of cells by diffusion through cell membrane, cell membrane partially permeable meaning it allows some molecules to cross easily, but other with difficulties or not at all
Osmosis
The net movement of particles in and out of cells from region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution through partially permeable membrane) through cell membrane
What happens when plant are placed in solution with higher potential energy than inside the cell?
Water moves into the cells via osmosis
Water molecules push the cell membrane against cell wall increasing the TURGOR PRESSURE in the cells making them TURGID
What happens to cells placed in a concentrated solution with lower water potential than inside cells?
Molecules move out of plant cells by osmosis, making them flaccid
Flaccid cells can negatively affect plants ability to support itself
Cell Underneath a microscope might look PLASMOLYSED
Immersing plant cells in solutions with different concentrations
- Cut cylinders of root vegetables (potatoes or radish) placing them into distilled water and sucrose solutions of increasing concentration
- Cylinders are weighed before placing into solution
- Leave in solution for 20-30 minutes and then removed, dried to remove excess liquid and reweighed
What happens if plant tissue gains mass
Water must’ve moved into plant tissue from solution surrounding it via osmosis
Solution surrounding tissue more dilute than plant tissue
What happens if plant tissue loses mass
Water must’ve moved out of plant tissue into solution surrounding it via osmosis
Tissue’s Surrounding solution more concentrated than plant tissue
What does it mean if there’s no overall change in mass
No net movement of water as the concentration in both plant tissue and solution surrounding it must be equal
Note that water will still be moving into and out of plant tissue, but no net movement in this case
What happens when water moves into a plant cell?
Vacuole Gets bigger, pushing cell membrane against cell wall
Water enetering the cell via osmosis makes cell rigid and firm
Why is this important for plants?
- The effect of all cells in a plant being rigid providing support and strength for the plant, making the plant test and upright with leaves held out to catch sunlight
- Pressure created by cell wall stops too much water from entering preventing cell from bursting
If they do not receive enough water, cell cannot remain rigid and firm (turgid)
What’s the importance of water potential on animals cells and tissues?
Animal cells :
- in solution they lose and gain water in result of osmosis
- do not have supporting cell wall
- if placed into sugar solution (with lower water potential than cell) it will lose water by osmosis becoming cremated (shriveled up)
-if placed into distilled water it will gain water by osmosis and since it doesn’t have cell wall creates turgor pressure, and will continue to do so until cell membrane is stretched to far an bursts
