Biology Flashcards
What are the parts of a plant cell?
8
Nucleus
Cell membrane
Cytoplasm
Ribosomes
Mitochondria
AND
Cell wall
Vacuole
ChloroplastsWhat are the parts of an animal cell?
5
Nucleus Cell membrane Cytoplasm Ribosomes Mitochondria
What’s the purpose of a nucleus?
To control the cell’s activities.
What’s the purpose of a cell membrane?
To control the passage of substances in and out of the cell.
What’s the purpose of cytoplasm?
It’s where chemical reactions take place.
What’s the purpose of ribosomes?
It’s where protein synthesis occurs (where proteins are made).
What’s the purpose of mitochondria?
It’s where energy is released during aerobic respiration.
What’s the purpose of a cell wall?
It keeps the plant rigid and supported.
What’s the purpose of chloroplasts?
They contain chlorophyll which so needed for photosynthesis.
What’s the purpose of a vacuole?
It’s filled with cell sap / water which is there all the time.
What is bacteria?
Very small, single celled organisms which are only a few micrometers. They don’t have a nucleus, mitochondria, chloroplast or vacuole.
Their DNA is found in the cytoplasm and controls the cell’s activities.
It has a flagellum (which looks like a tail).
They contain plasmids which helps them replicate.
They also have a slime capsule.
What’s yeast?
Single celled organisms
They have a nucleus
They reproduce by budding which is asexual an involves new cells forming from existing cells.
They have mitochondria but not chloroplasts.
What’s a specialised cell?
A cell with a specific job to do e.g. Root hair cells (increase surface area), sperm cell (the tail), neurons carry impulses from the receptors to the CNS.
Plant cells with many chloroplasts will be photosynthesising.
What is diffusion?
The spreading out / moving of (liquid or gas) particles from areas where the substance is concentrated to a less concentrated area (until it is evenly spaced out).
Where does diffusion occur in the body and plants?
The diffusion of oxygen into the cells of the body from the bloodstream as the cells are respiring (using up oxygen).
Glucose and nutrients in the intestine
CO2 in plants
What determines the net movement of particles across a cell membrane?
The concentration on either side of the membrane.
What’s a tissue?
A group of cells with similar structure and function.
What are the types of animal tissue?
Muscle - brings about movement
Glandular - produce substances like enzymes or hormones
Epithelial - covers the body
What are the types of plant tissue?
Epidermal - covers plant
Mesophyll - photosynthesise
Xylem and phloem - carry substances
What’s an organ?
An organ is made up of several types of tissues
E.g. The stomach is made up of muscular tissue (to churn food), glandular tissue (produce digestive juices) and epithelial (cover the stomach).
(The leaf, stem and root are plant organs which contain epidermal tissue, mesophyll tissue and xylem and phloem.)
What’s an organ system?
A group of organs which perform similar functions.
E.g. The digestive system is adapted to exchange substances with the environment. Insoluble molecules must be changed into soluble molecules.
The digestive system is a muscular tube including - glands (pancreas and salivary), stomach, small intestine, (liver bile) and large intestine.
(Duodenum is the first part of the small intestine directly beneath the stomach).
What’s photosynthesis?
When light energy is transferred into chemical energy.
What’s the equation for photosynthesis?
Carbon dioxide + water -> glucose + oxygen
6CO2 + 6H2O -> C6H12O6 + 6O2
How does photosynthesis occur?
It can only be carried out by green plants.
Chlorophyll in the chloroplasts absorbs the sun’s light energy.
CO2 is taken in by the leaves and water by the roots.
Chlorophyll traps the light energy for photosynthesis.
The energy is used to convert CO2 and water into glucose (a sugar).
What are limiting factors for photosynthesis?
Limiting factors are anything which prevent the rate of photosynthesis from increasing.
The factors include:
Light
CO2
Temperature
How does temperature affect the rate of photosynthesis?
If it’s cold, enzymes don’t work effectively and will slow the rate however, if above a certain point (45c?) the enzymes will denature and stop working completely.
How do plants use glucose?
It’s produced during photosynthesis which is then:
Converted into insoluble starch for storage
Used for respiration
Converted into fats and oils for storage
Used to produce cellulose which strengthens the cell walls
Used to produce proteins (and also need nitrate and mineral ions absorbed from the soil)
Name 3 substances used for storage in plants
Starch, fats and oils.
What physical factors affect the distribution of organisms?
Temperature Nutrients Light Water Oxygen CO2
Farmers can also artificially control these factors.
How can you make sure an investigation is valid?
All possible variables must be controlled
Use a comparative investigation
Repeatable and reproducible measurements
The method used must answer the question
Appropriate sample size
What’s the word equation for aerobic respiration?
Glucose + oxygen -> carbon dioxide + water (+ energy)
What are the levels of organisations?
Organelle Cells Tissues Organ Organ systems Organisms
How do respiration and photosynthesis differ at night and day?
Respiration always occurs but photosynthesis is only during day.
(Bright day) - same O and CO2 given out as CO2 and O in.
(Dim light) - less but same O and CO2 given out as CO2 and O in.
(Dark) - only CO2 given off, no photosynthesis
How are leaves adapted for photosynthesis?
Thin- allows gasses to reach cells easily
Wide and flat - larger surface area
Veins - carry water to leaves and glucose back, support leaves
Stomata - allows gasses to move in and out
Spongey layer - gas exchange easier
Palisade layer - lots of chloroplasts
What’s osmosis?
The diffusion of water from a dilute solution to a more concentrated solution through a partially permeable membrane.
What’s active transport?
When energy from respiration is used to move and uptake substances and particles against a concentration gradient.
How are villi in the stomach adapted?
Same as alveoli in lungs
Thin walls
Lots of capillaries
Large surface area
What’s transpiration?
Evaporation and diffusion of water.
What’s aerobic respiration?
It’s the release of energy from food when oxygen is available. (Oxygen and glucose)
Most of these reactions occur in the mitochondria.
Carbon dioxide and water are produced as waste products.
Respiration using oxygen.
Mitochondria are in all living things and is in every cell. Muscle tissue have lots of mitochondria since lots of energy is needed.
Photosynthesis and aerobic respiration are chemical opposites
How does our body use energy?
Working you muscles Transporting chemicals Absorbing food Sending messages via nerves Building cells Maintaining body temperature
What’s the equation for aerobic respiration?
Oxygen + glucose -> water + carbon dioxide [+ energy]
What happens to two flasks of peas, some boils and some germinating?
In the germinating flask, heat is produced as respiration is taking place so energy is released as heat.
The boiled flask had no temperature rise as respiration didn’t take place.
What’s the equation for anaerobic respiration?
Glucose -> lactic acid [+ energy]
It’s respiration without oxygen
What’s oxygen debt?
When we carry on vigorously breathing after exercise as the extra oxygen breaks down the lactic acid.
Amount of oxygen needed to get rid of the lactic acid.
What are proteins?
Proteins are made of long chains of amino acids e.g. Glycine.
The long chains are folded to produce specific shapes which depend on their functions.
The body makes most amino acids but essential amino acids which the body can’t produce must be consumed.
Chemical reactions in cells are controlled by proteins called enzymes.
Proteins can be: Catalysts (enzymes) Antibodies Hormones Structural components of tissue
What are some uses of proteins?
Structural proteins - muscles
Messenger proteins - hormones
Immune system protons - antibodies
Biological catalysts - enzymes
(Each enzyme has a specific shape that only fits the substance e it catalysed.
The area where the enzyme and substrate fits is called the active site.
Breaks down - catabolic
Builds up - anabolic
What are the digestive enzymes and where are they found?
Mouth - amylase
Stomach - protease / pepsin
Pancreas - protease and carbohydrase
Small intestine - lipase and carbohydrase
Protease - breaks proteins into amino acids
Carbohydrase - breaks carbohydrates “”
Lipase - breaks fats into fatty acids and glycerol
How does temperature and pH affect enzymes?
Enzymes work at different pHs - too high or low for them will denature the enzymes.
Enzymes work slowly in lower temperatures and faster at body temperature but too high and the they will denature.
What are the uses of enzymes?
Biological washing powder contains enzymes to help clean clothes / digest food stains.
Protease and lipase - stain digesters in washing powder, best at low temps
Papin - whitening toothpaste digests stains on teeth
Protease - pre digest protein e.g. Baby food
Invertase (carbohydrase) - breaks down starch into glucose syrup and is used in soft centre chocolates.
Lactose - makes milk lactose-free
Isomerase - converts glucose syrup to fructose syrup. Because fructose syrup is sweeter than glucose despite having the same amount of calories, it is used to make sweeteners since you would use less of it so it has uses less calories.
What does it mean if an enzyme has been denatured?
Factors such as temperature or pH alter the shape of the active site and prevent the enzyme from working.
What’s amylase?
A carbohydrase produced by the salivary glands, the pancreas and the small intestines.
It catalyses the digestion of starch into sugars in the mouth and small intestines.
