Biology 2a Flashcards
What is cytoplasm?
Gel-like substance where most of the chemical reactions happen. It contains enzymes that control these chemical reactions. (Plant and animal)
What does the nucleus do?
It contains genetic material that controls the activities of the cell (plant and animal)
What does the cell membrane do?
It holds the cell together and control what goes in and out. (Plant and animal)
What is the mitochondria?
Where most of the reactions for respiration takes place, energy is released that the cells need to work. (Plant and animal)
What are ribosomes?
These ads where proteins are made in a cell. (Plant and animal)
What are rigid cell walls for?
They are made of cellulose and support the cell/strengthens it. Only in plant cells.
What is a permanent vacuole?
It contains cell sap which is a weak solution of sugar and salts. Only in plant cells.
What are chloroplasts?
These are where photosynthesis occurs, which makes food for the plant. They contain a green substance called chlorophyll.
Is yeast a single or multi celled organism?
Yeast is a single-celled microorganism.
What organelles does a yeast cell contain?
A yeast cell contains a nucleus, cytoplasm and cell membrane, surrounded by a cell wall.
Are bacteria single or multi celled organisms?
Bacteria cells are single-celled microorganisms.
What organelles do bacteria cells contain?
Bacterial cells contain cytoplasm and a cell membrane, surrounded by a cell wall. The genetic material floats in the cytoplasm because they don’t have a nucleus.
What is the definition of diffusion?
Diffusion is the spreading out of particles from an area of high concentration to an area of low concentration.
Where does diffusion occur and why?
Diffusion happens in liquids and gasses as the particles are free to move about randomly.
If the difference in concentration is bigger, will diffusion happen at a faster or slower rate?
The bigger the difference in concentration, the faster the diffusion rate.
What organelle does diffusion take place in?
The cell membrane, dissolved substances move in and out of cells via diffusion. But only very small molecules can diffuse through the cell membrane. Eg starch and proteins can’t be diffused through the cell.
What are palisade leaf cells adapted for?
Palisade leaf cells are adapted for photosynthesis.
Where and why are there many chloroplasts in a palisade leaf cell?
Palisade leaf cells contain many chloroplasts for photosynthesis, most of them are stored on top of the leaf do they’re nearer to the light.
Why are palisade leaf cells tall?
They have a tall shape so their surface area is larger down the side of the leaf so more co2 is absorbed from the air.
What are guard cells adapted to do?
Guard cells are adapted to open and close pores.
What are the pores in a leaf called?
The stomata.
How is the guard cell specialised?
It is a special kidney shape which opens and closes the stomata in a leaf.
What happens when the plant has a lot of water, in terms of the guard cell?
The guard cell fills with water and becomes fatter, opening the stomata so gases can be exchanged for photosynthesis.
What happens when the plant is short of water, in terms of the guard cell?
The guard cells lose water and becomes flat and limp, closing the stomata. This stops too much water vapour escaping.
In a guard cell, are the inner walls or outer walls thinner?
Thin outer walls and thickened inner walls, to make the opening and closing work.
Why is it good that guard cells are sensitive to light?
Because this means they close at nigh to save water without losing out on photosynthesis.
What are red blood cells adapted to do?
Red blood cells are adapted to carry oxygen.
Why do red blood cells have a concave shape?
It gives the a big surface area for absorbing oxygen. It also helps them pass smoothly though the capillaries to reach body cells.
Red blood cells are packed with haemoglobin, what is it?
Haemoglobin in the pigment that absorbs the oxygen.
Do red blood cells have a nucleus?
No, so there is more room for haemoglobin.
What are sperm and egg cells specialised for?
Sperm and egg cells are specialised for reproduction.
What is the main function of an egg cell?
To carry the female DNA and to nourish the developing g embryo in the early stages as it contains a large food reserve to feed it with.
What happens, in terms of structure, when a sperm fuses with an egg?
The eggs membrane instantly changes its structure so no more sperm can get in. This makes sure that the offspring ends up with the right amount of DNA.
What is the function of a sperm?
To carry the male DNA to the female DNA.
How is the sperm cell specialised?
It has a long tail and streamlined head to help it swim to the egg. It contains lots of mitochondria in the cell to provide the energy needed. They also carry enzymes in their head to biggest through the egg cell membrane.
How are large multicellular organisms made up of organ systems? (what are the stages?)
Similar cells-> tissues-> organs->organ systems
What is the process by which cells become specialised for their job called?
Differentiation, it occurs during the development of a multicellular organism.
What are three examples of tissues in mammals and what are they for?
Muscular tissue - contracts to move whatever is is attached to.
Glandular tissue - makes and secretes chemicals like enzymes and hormones.
Epithelial tissue - covers some parts of the body, eg the inside of the gut.
What is a tissue?
A group of similar cells working together to carry out a function.
What is an organ?
A group of different tissues working together to perform a certain function.
The stomach is a muscle, what three tissues is it made up of and why?
Muscular tissue - moves the stomach wall to churn up food.
Glandular tissue - makes digestive juices to digest food (acids).
Epithelial tissue - covers the outside and inside of the stomach.
What is an organ system?
A group of organs working together to perform a particular function.
The digestive system is an example of an organ system, what organs does it contain and end?
Glands (eg.pancreas and salivary glands) - produces digestive juices/acids.
Stomach and small intestine - digests food.
Liver - produces bile.
Small intestine - absorbs soluble food molecules.
Large intestine - absorbs water from undigested food, leaving faeces .
What does the digestive system do?
It exchanges materials with the environment by taking in nutrients and releasing substances such as bile.
What are some of the organs that plants are made of?
Stems, roots and leaves etc
What tissues are leaves made of?
Mesophyll tissue-Where most of the photosynthesis in a plant occurs
Xylem and Phloem-They transport things like water, mineral ions and sucrose around the plant
Epidermal tissue-This covers the whole plant
What is the equation for photosynthesis?
Sunlight
Carbon dioxide+water———->glucose+oxygen
Chlorophyll
What does photosynthesis do?
It is the process that produces food in plants and algae. The food it makes is glucose
What does chlorophyll do?
Chlorophyll absorbs sunlight and uses its energy to convert carbon dioxide from the air and water from the soil into glucose. Oxygen is also produced as a by-product
What are the four raw materials for photosynthesis?
Sunlight
Chlorophyll
water-reaches the cell via the xylem
CO2-Diffuses into the leaf
What is it called when a plant has a lack of water?
It is a limiting factor
What three things affect the rate of photosynthesis?
Temperature, light intensity and the amount of carbon dioxide
Any of the factors affecting the rate of photosynthesis can become limiting factors, depending on the environmental conditions, what are they?
At night the light is a limiting factor
In winter, temperature is a limiting factor
Also if its warm enough and bright enough, the amount of CO2 is usually limiting
If you were to do an experiment to work out the ideal conditions for a plant, what would be the best plant to use?
A water plant like Canadian pondweed
What does light provide for photosynthesis?
Light provides the energy needed
What would be the pattern on a graph of the rate of photosynthesis as the light intensity increases?
The rate of photosynthesis will increase steadily but then eventually it will stop moving because the temperature and CO2 will become limiting factors
Interesting factoid if you flip this card over…
The graph for too much co2 would be the same as it would be for too much light.
How can the amount of CO2 in a plant be controlled?
CO2 can be controlled by dissolving different amounts of sodium hydrocarbonate in the water which gives off carbon dioxide
What happens to the rate of photosynthesis if the temperature keeps increasing?
At first the rate of photosynthesis would increase but then it would stop completely because at 45 degrees, the enzymes needed for photosynthesis are destroyed
How do greenhouses keep plants warm?
They trap the sun’s heat. Heaters can be used in winter and ventilation in summer to control the temperature
How can greenhouses control the amount of co2?
By using paraffin heaters because carbon dioxide is a by-product
What is another benefit of greenhouses apart from controlling the temperature, light and co2?
It keeps the plants free from pests and diseases. Also minerals can be supplied to the plants
What are the five ways that plants use glucose?
For respiration Making cell walls Making proteins Stored in seeds Stored as starch
How do plants use glucose for respiration?
It is manufactured in their leaves and then some is used for respiration. This releases energy which enables them to convert the rest I to other useful substances
How do plants use glucose for making cell walls?
Glucose is converted into cellulose for string cell walls especial in a rapidly growing plant
How do plants use glucose for making proteins?
Glucose is combined with nitrate ions absorbed from the soil to make amino acids, which are then made into proteins
How is glucose stored in seeds?
It is turned into lipids (fats and oils)
Margarine can be made from them and seeds also store starch
How is glucose stored as starch
It is turned into starch and then stored in the stems, roots and leaves ready for when photosynthesis isn’t happening like in winter
Starch is insoluble which is better for storing it
What are some environmental factors that affect organism distribution?
Temperature Availability of water Availability of oxygen and water Availability of nutrients Amount of light
IN EXPERIMENTS, MAKE SURE YOUR RESULTS ARE REPEATABLE AND REPRODUCIBLE
IN EXPERIMENTS, MAKE SURE YOUR RESULTS ARE REPEATABLE AND REPRODUCIBLE
