Unit 2A - Cells, Organs And Populations Flashcards
What do plant cells have but not animals cells?
Cell wall, vacuole, chloroplasts
What are the parts in an animal cell?
Nucleus, cytoplasm, cell membrane, mitochondria and ribosomes
What does the nucleus do?
Contains genetic materials and controls the cell
What does the cytoplasm do?
It is a gel-like substance that contains enzymes and it is where the chemical reactions happen
What does the cell membrane do?
Holds the cell together and controls what goes in and out
What do the mitochondria do?
Where respiration happens
What do ribosomes do?
Where the protein are made
What does the cell wall do?
Supports and strengthens plant cells
What is the vacuole?
A weak solution of sugar and salts
What happens in the chloroplasts ?
They contain chlorophyll and is where photosynthesis happens
Name two single called microorganisms
Yeast and bacteria
What is the definition of diffusion?
Diffusion is the spreading out of particles from an area of high concentration to area of low concentration
How do dissolved substances move in and out of substances?
Diffusion
What molecules can fit through a cell membrane?
Oxygen, glucose, amino acids and water
Why can’t starch and proteins fit through the membrane?
They are too big
What are palisade cells adapted for?
Photosynthesis?
How are palisade cells adapted for their job?
Contain more chloroplasts than normal, and they are at the top so they are nearer the light for photosynthesis. Tall shape for a large surface area to absorb more CO2. Thin shape so they can be closely packed on the top of the cell.
What are guard cells adapted for ?
To open and close pores
How are guard cells adapted?
They are a special kidney shake which open when the plant has lots of water and close when it doesn’t, this controls gas exchange and water loss. They are also sensitive to light and close at night to save water
What are red blood cells adapted for?
To carry oxygen
How are red blood cells adapted?
Concave shape for a large surface area to absorb for oxygen and to help them pass smoothly through capillaries. No nucleus and loads of haemoglobin to absorb more oxygen.
What are haemoglobin?
The pigment that absorbs oxygen
What cells are adapted for reproduction?
Sperm and egg
How is the sperm cell adapted for its function?
Long tail and streamlines to swim to eggs, contains loads of mitochondria for energy and has enzymes in its head to guest through the egg cell membrane
How is the egg cell adapted ?
Contains a lot of food reserves to fed the embryo, when the sperm fuses the egg cell membrane instantly changes to stop any more sperm getting in
Cells together form?
Tissue
Tissues together form?
Organs
Organs together form?
Organ systems
Define tissue
Tissue is a group of similar cells that work together to carry out a particular function
What is an organ
An organ is a group of different tissues that work together to perform a certain function
What is a group of organs working together to perform a particular function called?
Organ system
What tissue contracts to move whatever it is attached to and what is its purpose in the stomach?
Muscular tissue - in the stomach it moves the stomach wall to churn ou the food.
What does glandular tissue do and what is its purpose in the stomach?
It secrets chemicals like enzymes and hormones, in the stomach it produces digestive juices
What tissue covers the outside and inside of the stomach ?
Epithelial tissue
What organs are in the digestive system?
Pancreas, salivary glands, stomach, small intestine, large intestine
How does the digestive system exchange material with the environment ?
It takes in nutrients and releases substances such as bile
What is the name if the tissue where photosynthesis occurs?
Mesophyll
What do the xylem and phloem do?
Transports things like water, mineral ions and sucrose around the plants
What tissue covers the whole plant?
Epidermal tissue
What is the photosynthesis equation?
Carbon dioxide + water ———> glucose + oxygen
What is glucose to the plant?
Food
What do chlorophyll do?
They absorb sunlight and uses its energy to convert carbon dioxide and water into glucose. Oxygen is a by-product
What three factors affect the rate of photosynthesis ?
Light, CO2 and temperature
What experiment can you do to find the ideal conditions for photosynthesis ?
Using Canadian pondweed and different conditions, you can easily measure the amount of oxygen produced with a gas syringe. The more oxygen produced the faster the rate of photosynthesis
Why does light affect the rate of photosynthesis?
Light provides energy needed for photosynthesise and so without light photosynthesis can’t happen
If it’s stopping photosynthesis what is it called?
Limiting factor
What happens if you increase the light intensity and CO2 levels?
The rate of photosynthesis but only yo to certain point as they are no longer the limiting factor
Why does the amount of CO2 affect the rate of photosynthesis ?
It is a raw material need for photosynthesis
How can you test the affects of CO2 levels on photosynthesis?
Using different amounts of sodium a carbonate dissolved in water as in water in gives off CO2
If the temperature is too low why is it a limiting factor?
If the temperature is too low then the enzymes work more slowly and so photosynthesis happens more slowly
What happens to the rate of photosynthesis if the temperature is too high?
If a plant gets too hot the enzymes are damaged and stop working, enzymes are needed for photosynthesis
What temperature are all the enzymes destroyed?
45c
What do you use to artificially create the ideal conditions for farming?
Use a greenhouse
Why do greenhouses increase the rate of photosynthesis?
They trap the suns heat so that temperature isn’t the limiting factor, at night they use artificial light as light is needed for photosynthesis, use a paraffin heater as it gives as a by-product of CO2 so CO2 isn’t a limiting factor.
What is another advantage if using a greenhouse?
Keeps the plants free from pest and disease.
What are the five ways plants use glucose?
For respiration, making cell walls, making proteins, stored in seeds, stored as starch
Why do plants use glucose in respiration?
In release energy which allows them to convert the glucose into various other useful substances
What is glucose converted to to make cell walls?
Cellulose
How is glucose changed in proteins?
Glucose is combined with nitrate ions in the soil to make amino acids, which are then made into proteins
What is glucose stored as in seeds?
Lipids (fats and oils)
Why is glucose stored as starch?
Starch is insoluble which makes it better than storing than glucose as glucose would draw in a lot of water and swell
What are the two ways you can measure the distribution if organisms?
Transects and quadrats
What is the place where an organism live called?
Habitat
What is the distribution of an organism ?
Where an organism is found
What are the five environmental factors that affect distribution?
Temperature, availability of water, nutrients, oxygen and carbon dioxide and the amount of light
What’s the difference between quadrats and transects?
A quadrat is a square frame enclosing a known area, a transects is when you use the quadrats to study distribution along a line
How can you make the quadrats and transects more reliable?
Use a random sample or take a larger sample
How are you results valid?
If they are reliable and answer the original question
How would you make your results more valid?
Control all the variables so that you know that the difference in distribution is due to one environmental factor.
