B2.2 + 3 Tissues, organs, organ systems and Photosynthesis Flashcards
What is a tissue?
A group of similar cells working together to perform a particular function
Name 3 types of tissue in mammals and their purposes.
- Muscular tissue which contracts to move whatever it is attached to.
- Glandular tissue which makes and secretes chemicals e.g enzymes and hormones
- Epithelial tissue which covers parts of the body
What is the purpose of muscular tissue in the stomach?
Moves the stomach wall to churn up the food
What is the purpose of glandular tissue in the stomach?
Makes and secretes digestive juices and enzymes to digest the food
What is the purpose of epithelial tissue in the stomach?
Covers the outside + inside wall of the stomach, stops it digesting itself
What is digestion?
The breaking down of large insoluble molecules to smaller soluble ones to be absorbed in the bloodstream
What is an organ?
A group of different tissues working together to perform a particular function.
What happens in the mouth with digestion?
- Food is cut into smaller pieces with teeth (larger surface area for enzymes to work on)
- Amylase acid is produced here by salivary glands and begins to break down carbohydrates into glucose
Where is bile produced?
Livers
Where is bile stored?
Gall bladder
What are the two purposes of bile?
- To emulsify fat for a bigger surface area for lipase to work on
- To neutralise stomach acid so enzymes can work in the small intestine
What happens in the small intestine with digestion?
- Finishing breaking down insoluble molecules to soluble molecules
- Lipase enzymes break down lipids and amylase breaks starch down
- All diffuses into the blood
What is happens in the oesophagus?
Muscles push down food into the stomach
What happens in the stomach with digestion?
- Pepsin breaks protein down
What are the two purposes of stomach acid?
- To protect against bacteria
- To create the right PH for pepsin
What is the purpose of the pancreas?
To produce enzymes for the small intestine (e.g insulin, lipase, amylase)
What happens in the large intestine with digestion?
Excess water is absorbed and faeces are created
What is an organ system?
A group of similar organs working together to perform a particular function.
What are the function of glands in digestive system?
They produce digestive juices and enzymes
What are the main organs of a plant? (3)
- Stems
- Roots
- Leaves
What are the main tissues of a plant and their functions? (3)
- Epidermal tissue - covers the plant
- Xylem and phloem tissue - transport water, mineral ions and sucrose around the plant
- Mesophyll tissue - where photosynthesis in a plant occurs
What is the equation for photosynthesis?
carbon dioxide + water –light energy–> glucose + oxygen
Where does carbon dioxide come from in the plant?
Diffuses into the leaf through the stomata
Where does water come from in a plant?
From root hair cells, travelling up the xylem.
What is the role of chlorophyll in photosynthesis?
To absorb sunlight and use the energy to convert carbon dioxide and water into glucose.
What happens to the oxygen produced by photosynthesis?
It leaves the plant as a waste gas
Name 3 limiting factors for photosynthesis.
- Temperature
- Carbon dioxide
- Light intensity
How does increasing light intensity/carbon dioxide affect the rate of photosynthesis?
- As they increase, so does the rate of photosynthesis because light is a limiting factor.
- At a certain temperature, a constant rate is reached as the other two factors become limiting factors.
How does increasing temperature affect the rate of photosynthesis?
- As temperature increases at first so does the rate of photosynthesis as more energy means more collisions between the particles meaning more reactions.
- After the optimum temperature is reached (45 degrees c) increasing temperature becomes a limiting factor as it denatures the enzymes by changing their active site, so the rate of photosynthesis goes down.
- Name 5 uses of glucose in plants
- Respiration
- Making cell walls
- Storage as starch
- Storage as seeds
- Protein synthesis
How is glucose used for respiration?
- Energy is released enabling them to convert the rest of the glucose into other useful substances.
- Energy is also used to gather minerals from the soil (ATP for active transport)
How is glucose used for protein synthesis?
Plants combine glucose and nitrate ions to make amino acids which are then made into proteins
How is glucose used for storage as starch?
- Plants convert glucose into starch for storage as starch is insoluble. Glucose is soluble and would draw lots of water into plant cells making them swell up.
- Some plants store them in bulbs/tubers
- Potato and parsnip plants store starch underground over the winter so new plants can grow from it in the spring.
How is glucose used for storage as seeds?
- Glucose is turned into lipids for storing in seeds and we can get cooking oil from them (e.g sunflower oil)
How is glucose used for making cell walls?
Glucose is converted into cellulose for making strong cell walls
How do farmers create ideal conditions for farming in greenhouses?
- Greenhouses trap some of the earth’s heat, in winter a farmer might use a heater as well.
- In summer, ventilation and shades can be used to cool things down.
- Supplying light artificially so more photosynthesis takes place
- Carbon dioxide levels are increased (e.g using a paraffin heater)
- Adding fertilisers to provide all the minerals needed for a healthy growth
- Keeping them enclosed makes it easier to keep them free from pests and disease
What are nitrate ions used for in plants?
Building proteins and growth
What are magnesium ions used for in plants?
Photosynthesis - chlorophyll contains it
What are potassium ions used for in plants?
Respiration and photosynthesis
What are phosphate ions used for in plants?
Respiration and growth
How does the digestive system exchange materials with the environment?
By taking in nutrients and releasing substances (e.g bile)
What is the purpose of organ systems in large multicellular organisms?
To transport and exchange materials
What 3 environmental conditions affect photosynthesis?
- Time of day
- Season
- Weather
