2a Flashcards
What are the five major parts of an animal cell?
Nucleus, Cytoplasm, Cell membrane, Mitochondria, Ribosomes
What does the Nucleus do in an animal cell?
Contains genetic material- controls the activities of the cell
What does the Cytoplasm do in an animal cell?
Gel-like substance where most of the chemical reactions happen. contains enzymes to control chemical reactions
What does the Cell Membrane do in an animal cell?
Holds the cell together and controls what goes in and out
What do the Mitochondria do in an animal cell?
These are where most of the reactions for respiration take place. Respiration releases energy that the cell needs to work.
What do the Ribosomes do in an animal cell?
These are where proteins are made in the cell
What are the 3 extra parts of a plant cell?
Rigid cell call, Permanent vacuole, Chloroplasts
What does the rigid Cell wall do in a plant cell?
Made of cellulose. It supports the cell and strengthens it
What does the Permanent vacuole do in a plant cell?
Contains cell sap, a weak solution of sugar and salts
What do the Chloroplasts do in a plant cell?
These are where photosynthesis occurs, which makes food for the plant. They contain a green substance called chlorophyll
What is yeast and what does it contain?
Yeast is a microorgansim. A yeast cell has a nucleus, cytoplasm and a cell membrane surrounded by a cell wall
What do Bacteria cells contain?
Has a cytoplasm and a cell membrane surrounded by a cell wall. The genetic material floats in the cytoplasm because bacterial cells don’t have a nucleus
Define diffusion
Diffusion is the spreading out of particles from an area of high concentration to an area of low concentration
What ‘states’ can diffusion happen in?
Solution and gases- particles are free to move about randomly
If there is a bigger difference in concentration, will the diffusion rate be faster or slower?
The diffusion rate will be faster
Give four examples of molecules that can diffuse through cell membranes
Oxygen, amimo acids, water, glucose
What are palisade leaf cells adapted for?
Photosynthesis
How are palisade leaf cells adapted for photosynthesis?
Packed with chloroplasts at top so nearer to light, tall shape so surface area exposed for absorbing carbon dioxide, thin shape means can pack lots of them in at the top of the leaf
What are Guard cells adapted to do?
Open and close pores
How are Guard cells adapted to open and close pores?
Special kidney shape which opens & closes stomata, sensitive to light so close at night, thin outer walls and thickened inner walls make the opening and closing work
What happens to the guard cells when a plant has lots of water?
The guard cells fill and go plump which makes the stomata open so gases can be exchanged for photosynthesis
What happens to the guard cells when a plant doesn’t have enough water?
The guard cells lose water and become flaccid, making the stomata close, this helps too much water vapour escaping
Why do guard cells close at night?
To save water without losing out on photosynthesis
What are the two main functions of a guard cell?
Allowing gas exchange & controlling water loss with a leaf
How are Red Blood Cells adapted to carry oxygen?
Concave shape gives big surface are for absorbing oxygen and helps them to pass smoothly through capillaries to reach body cells, packed with haemoglobin that absorbs oxygen, no nucleus so more room for haemoglobin.
What are the main functions of the egg cell and how is it specialised for this?
To carry the female DNA and to nourish the developing embryo in the early stages. It contains huge food reserves to feed the embryo
How are the sperm and egg cells specialised for reproduction?
When a sperm fuses with the egg, the eggs membranes instantly changes its structure to stop any more sperm getting in. This makes sure the offspring end up with the right amount of DNA
What are the main functions of the sperm and how is it specialised for this?
The function of a sperm is to get the male DNA to the female DNA. It has a long tail and a streamlined head to help it swim to the egg. There are a lot of mitochondria in the cell to provide the energy needed and enzymes in head to digest through the egg cell membrane
When does differentiation occur?
During the development of a multicellular organism
What is the cell organisation?
Specialised cells form tissues which form organs which form organ systems
What does Muscular tissue do?
Contracts to move whatever its attached to
What does Glandular tissue do?
Makes and secretes chemicals like enzymes and hormones
Explain why its important that a plant doesn’t get too hot
The enzymes it needs for photosynthesis and its other reactions will be damaged
What does Epithelial tissue tissue do?
Covers some parts of the body e.g. inside of the gut
Give an example of an organ
The stomach
Give an example of an organ system
The digestive system
What are the three main tissues that plants are made of?
Mesophyll tissue, Xylem and Phloem and Epidermal tissue
What does the Mesophyll tissue do?
Where most of the photosynthesis in a plant occurs
What do the Xylem and Phloem do?
Transport things like water, mineral ions and sucrose around the plant
What does the Epidermal tissue do?
This covers the whole plant
What is the equation for photosynthesis?
Carbon dioxide + water = (+sunlight+chlorophyll) = glucose + oxygen
Where does photosynthesis happen?
Inside the chloroplasts
What do chlorophyll do
Absorb sunlight and uses its energy to convert carbon dioxide and water into glucose. oxygen is also produced as a by-product
From top to bottom what order are the tissues in? (in a plant)
Epidermis, xylem and phloem are inside of the mesophyll, epidermis
What three things is the rate of photosynthesis affected by?
The intensity of light, the volume of CO2 and the temperature
Why does the rate of photosynthesis only increase up to a certain point?
There will always be a limiting factor
How can you artificially create the ideal conditions for farming?
In a greenhouse. Trap the suns heat so that the temperature doesn’t become limiting. Supplied with artificial light after the sun goes down. Paraffin heater to heat greenhouse co2 is by-product
What are the five ways that plants use glucose?
For respiration, making cell walls, making proteins, stored in seeds and stored as starch
How do plants use glucose for respiration?
Plants manufacture glucose in their leaves, they then use some of the glucose for respiration, this releases energy which enables them to convert the rest of the glucose into various other useful substances, which they can use to build new cells and grow.
How do plants use glucose for making cell walls?
Glucose is converted into cellulose for making strong cell walls, especially in a rapidly growing plant.
How do plants use glucose for making proteins?
Glucose is combined with nitrate ions to make amino accuse which are then made into proteins
How do plants store glucose in seeds
Glucose is turned into lipids for storing in seeds. Sunflower seeds, for example, contain a lot of oil - we get cooking oil and margarine from them. Seeds also store starch
How do plants store glucose as starch?
Glucose is turned into starch and stored in roots, stems and leaves, ready for use when photosynthesis isn’t happening, like in the winter. Starch is insoluble which makes it much better for storing than glucose- doesn’t swell up
What is a habitat?
The place where an organism lives
What six environmental factors affect where an organism is found?
Temperature, availability of water, availability of oxygen and carbon dioxide, availability of nutrients, amount of light
What is a quadrat?
A square frame enclosing a known area e.g. 1m x 1m
How do you work out population size?
Mean number of organisms per m2 times by the total area of the habitat
How do you study the distribution of organisms along a line?
Using a transect, use quadrat along a line
When collecting environmental data what do you need to think about?
Make sure your results are repeatable and reproducible and have all the correct variables controlled
