B2 Biology Flashcards
What additional features has plants cell got?
cell wall, and often have chloroplasts and a permanent vacuole.
What features of animal cells and plant cells have in common?
a nucleus, cytoplasm, cell membrane, mitochondria and ribosomes.
Explain the function of : Cell membrane Cytoplasm Nucleus Mitochondria Ribosomes
Nucleus-Contains genetic material, which controls the activities of the cell
Cytoplasm-Most chemical processes take place here, controlled by enzymes
Cell membrane-Controls the movement of substances into and out of the cell
Mitochondria-Most energy is released by respiration here
Ribosomes-Protein synthesis happens here
ExplAin the function of
Cell wall
Vacuole
Chloroplast
Cell wall-Strengthens the cell
Chloroplasts-Contain chlorophyll, which absorbs light energy for photosynthesis
Permanent vacuole-Filled with cell sap to help keep the cell turgid
What is the function and adaptation of a leaf cell
Absorbs light energy for photosynthesis Packed with chloroplasts.
Regular shaped, closely packed cells form a continuous layer for efficient absorption of sunlight.
What is the function and adaptation of a root hair cell?
Absorbs water and mineral ions from the soil
Long ‘finger-like’ process with very thin wall, which gives a large surface area.
What is the function and adaptation of a sperm cell?
Fertilises an egg cell - female gamete
The head contains genetic information and an enzyme to help penetrate the egg cell membrane. The middle section is packed with mitochondria for energy. The tail moves the sperm to the egg.
What is the function and adaptation of red blood cell
Contains haemoglobin to carry oxygen to the cells.
Thin outer membrane to let oxygen diffuse through easily. Shape increases the surface area to allow more oxygen to be absorbed efficiently. No nucleus, so the whole cell is full of haemoglobin.
What is diffusion
Diffusion occurs when particles spread. They move from a region where they are in high concentration to a region where they are in low concentration.
Example of diffusion in the body
In the lungs, the blood will continue to take in oxygen from the alveolar air spaces provided the concentration of oxygen there is greater than in the blood. Oxygen diffuses across the alveolar walls into the blood, and the circulation takes the oxygen-rich blood away.
What is a tissue ?
A tissue is a group of specialised cells that have a similar structure and function.
What are the function of these tissue ?
Muscular tissue
Glandular tissue
Epithelial tissue
Muscular tissue -Contracts, bringing about movement
Glandular tissue- Produces substances such as enzymes and hormones
Epithelial tissue-Covers some parts of the body
What is the organ system?
Organ systems are groups of organs that carry out a particular function.
What are the functions of the main tissue and organ in the digestive system? Pancreas and salivary glands Stomach Liver Small intestine Large intestine
Pancreas and salivary glands-Produce digestive juices
Stomach-Digests food
Liver-Produces bile
Small intestine-Digest and absorb soluble food
Large intestine-Absorbs water from undigested food, producing faeces
What are the function of these plant tissue?
Epidermal tissue
Mesophyll
Xylem and phloem
Epidermal tissue-Covers the plant
Mesophyll-Carries out photosynthesis
Xylem and phloem-Transport of substances around the plant
How are leaves adapted to absorbing sunlight for photosynthesis ?
Chlorophyll-To absorb sunlight
Large surface area-To absorb more light
Stomata-To let carbon dioxide diffuse into the leaf
Thin-Short distance for carbon dioxide to diffuse into leaf cells
Network of veins-To support the leaf and transport water and carbohydrates
What factors can limit photosynthesis ?
This process is called photosynthesis. Temperature, carbon dioxide concentration and light intensity are factors that can limit the rate of photosynthesis.
What happens during photosynthesis ?
*explain equation *
Light energy is absorbed by chlorophyll, a green substance found in chloroplasts in some plant cells and algae
Absorbed light energy is used to convert carbon dioxide (from the air) and water (from the soil) into a sugar called glucose
Oxygen is released as a by-product
Equation of photosynthesis
Carbon dioxide + water –> glucose + oxygen
What is the waste product in photosynthesis ?
Oxygen
What is glucose used for?
It is used for respiration and stored in the plant as starch
Other than glucose being stored as starch to release energy how else can glucose be used?
Cellulose - which strengthens the cell wall
Proteins - such as enzymes and chlorophyll
what is nitrate in plant needed for?
Plants also need nitrates to make proteins. These are absorbed from the soil as nitrate ions.
What are the physical factors that may affect organisms
Temperature Amount of light Availability of water Availability of nutrients Availability of oxygen and carbon dioxide.
Definition of Environment Habitat Population Community Ecosystem
Environment-All the conditions that surround a living organism
Habitat-The place where an organism lives
Population-All the members of a single species that live in a habitat
Community-All the populations of different organisms that live together in a habitat
Ecosystem A community and the habitat in which it lives
What does Transect mean
is a line across a habitat or part of a habitat. It can be as simple as a string or rope placed in a line on the ground. The number of organisms of each species can be observed and recorded at regular intervals along the transect.
What does quadrant mean?
A quadrat is usually a square made of wire. It may contain further wires to mark off smaller areas inside, such as 5 x 5 or 10 x 10 squares. The organisms underneath, usually plants, can be identified and counted.
Why must quadrat and Transect be used as a technique of sampling?
It is usually not possible to count the entire population of a particular organism in its habitat.
What are protein up from?
Proteins are made from long chains of smaller molecules called amino acids. These long chains are folded into particular shapes.
Why is the shape of protein important ?
This is important in relation to how antibodies and enzymes work.
What are enzymes ?
Enzymes are biological catalysts. There are optimum temperatures and pH values at which their activity is greatest. Enzymes are also proteins.
What is it said to be if a shape of an enzyme has changed?
Denatured - May no longer work
How are protein polymers ?
They are built up in cells when monomers called amino acids join together end to end:
Lots of amino acid molecules →
Lots of amino acid molecules → a protein molecule
What does protein act as
Proteins act as:
Structural components of tissues (such as muscles)
Hormones (such as insulin)
Antibodies (part of the body’s immune system)
Biological catalysts (enzymes)
In-depth what is the definition and process of an active site ?
Enzymes are proteins folded into complex shapes that allow smaller molecules to fit into them. The place where these substrate molecules fit is called the active site.
How can enzymes denature ?
Enzymes can be denatured by high temperatures or extremes of pH.
How would a graph show the effect of enzyme with increasing temperature?
The graph shows the typical change in an enzyme’s activity with increasing temperature. The enzyme activity gradually increases with temperature up to around 37ºC, or body temperature. Then, as the temperature continues to rise, the rate of reaction falls rapidly as heat energy denatures the enzyme.
How would a graph show the effect enzymes with PH ?
Example ?
Changes in pH also alter an enzyme’s shape. Different enzymes work best at different pH values. The optimum pH for an enzyme depends on where it normally works. For example, intestinal enzymes have an optimum pH of about 7.5. Enzymes in the stomach have an optimum pH of about 2.
Different enzymes catalyse different digestion reactions.
What are the reaction catalyse with these enzyme below
Amylase
Protease
LipaseLipids
Amylase Starch → sugars
Protease Proteins → amino acids
LipaseLipids → fatty acids + glycerol
Where is each enzyme produced ?
Amylase
Protease
Lipase
Amylase-Salivary glands, pancreas, small intestine
Protease-Stomach, pancreas, small intestine
Lipase-Pancreas, small intestine