Cells, Tissue and Organs/ Osmosis and DiffusionA cell is a single unit of life. It contains many organelles such as the nucleus or chloroplasts.
Gene, Chromosome, Nucleus.
smallest------------------------>biggest.
Chloroplast, Palisade Mesophyll Cell, Tissue, Organ System, Organism
smallest-------------------------------------------------------------------------->biggest
Protoplasm refers to the organelles in a cell.
What is the plant tissue that transports water?
Xylem vessel.
What is the cell that transports oxygen in humans?
Red Blood Cell.
Xylem vessel has no protoplasm, true or false?
TRUE. It does not have any protoplasm so as to not hinder water movement.
I have long threads that can carry information. What am I?
Chromosome.
Which animal cell, when placed in distilled water, will burst?
Red blood cell. It will burst as it does not have a cell wall.
What type of leaf does not completely contain chlorophyll?
Varigated leaf. (The green parts contain chloroplasts and the white parts DO NOT CONTAIN CHLOROPLASTS.)
Photosynthesis can occur when there is respiration, true or false?
True.
Respiration occurs all the time, true or false?
True.
What should one do to only allow respiration to take place in plants?
Place the plant in a dark room, with no sunlight.
How does one test for carbon dioxide?
Limewater. The limewater will turn chalky, into a white precipitate, when in contact with carbon dioxide.
How do we know that carbon dioxide is needed for photosynthesis?
Have 2 plants, use one as a control. Cover both plants with a plastic bag, and in one, place soda lime. The soda lime will absorb all the carbon dioxide.
What are the raw materials needed for photosynthesis?
Water and Carbon Dioxide.
What are the conditions needed for photosynthesis?
Chlorophyll and Sunlight.
What is the end product of photosynthesis?
Oxygen and Glucose.
What is glucose used for?
It is used for respiration in plants.
Mitochondrion (singular form), Mitochondria (plural form)
It's function is to transport oxygen in cells, which will transport oxygen to different parts of the body. The muscle cell and the sperm cell contains the most mitochondria.
Water diffuses through partially permeable membranes like the visking tubing faster than glucose. It diffuses by osmosis because there is a higher concentration in the water than in the glucose. The glucose can diffuse through a visking tubing, but it diffuses slower than water.
Potato A is placed in a concentrated salt solution. Water will leave the potato by osmosis. There is a higher water concentration in the cell sap than in the salt solution. The potato will become soft and flaccid.
Potato B is placed in water. Water will enter the potato by osmosis. There is a higher water concentration in the water than in the cell sap. The potato will become hard and turgid.
Starch can pass through cell walls, because the cell wall is fully permeable. However, starch cannot pass through the cell membrane as the cell membrane is partially permeable.
A control has ALL FACTORS PRESENT.
Osmosis is the net movement of water molecules from a solution of higher water potential to a solution of lower water potential through a partially permeable membrane.
Diffusion is the most common type of passive transport. It is also the net movement of molecules from a region of high concentration to a region of low concentration, and it is a slow process.
Diffusion stops when molecules are dispersed evenly, with no concentration gradient, and a state of equilibrium is reached.
Excessive water intake causes an animal cell to swell and eventually bursts.
Excessive water loss causes cell to shrivel and shrink.
Diffusion takes place the fastest in gas, followed by liquid, and it takes place the slowest in solids.
Why is diffusion important?
(1)Gaseous exchange (oxygen, carbon dioxide) during respiration and photosynthesis.
(2)Excreting waste products like ammonia, water and mineral salts.
(3)Absorption of digest food into blood through walls of small intestine.
(4)Enables animals to detect food by smell.
Steps For a Starch Test:
(step 1) Boil the leaf for 5 minutes. This is to stop all enzyme action in the leaf.
(step 2) Immerse the boiled leaf in ethanol to decolourize the leaf.
(step 3) Put the decolourized leaf in hot water to soften it.
(step 4) Remove the leaf from water and drop iodine on it's surface.
(step 5)Check if the iodine turns blue-black. This will show that starch is present.
Factors that speed up diffusion:
(1)Temperature - the higher the temperature, the higher the rate of diffusion.
(2)Size of particles - small molecules are able to diffuse faster than large molecules.
(3)Thickness of barrier - thicker cell walls in plant cells, the slower the rate of diffusion. Call membranes in plants and animals are about the same thickness and permeability.
(4)Surface area - the larger the surface area, the faster diffusion can take place.
(5)Concentration gradient - The greater the gradient, the higher the rate of diffusion.
(6) State of matter - diffusion is slow in solids, faster in liquids and fastest in gases.
Diffusion in living organisms:
(1) Diffusion of digested food substances through the cells lining the small intestine and into the blood.
(2) Diffusion of oxygen, mineral salts and water from the surrounding soil into a root hair cell.
Helping Points/ Points to Consider
1) When asked to describe a cell, describe it's function and structure.
KEYWORDS :
osmosis, diffusion/diffuse, high/higher water concentration, low/lower water concentration, flaccid, turgid, homogeneously spread, partially permeable, fully permeable,
