Edexcel Biology chapter 1

Pregunta	Respuesta
Recall the eight characteristics of living organisms and explain them.	1) require nutrition - make own food/eat other organisms 2) excrete - get rid of toxic waste products 3) move - by action of muscles in animals, slow growth movements in plants 4) grow and develop - increase in size and mass using materials from food 5) respire - get energy from food 6) respond to stimuli - sensitive to surroundings 7) reproduce - produce offspring 8) control - their internal conditions
Draw and label an animal cell and a plant cell.	Image: 7b413269-166e-4ad6-8977-58b12f142890.gif (image/gif)
Describe the functions of the nucleus.	The nucleus is in almost every single cell except for the few that don't live for very long, or the ones that are dead. It controls all the activities of the cell.
Describe the functions of the cytoplasm.	The cytoplasm is the material that makes up the cell. It's made of several different structures, and it has a jelly-like texture, so therefore it's in between a solid and a liquid.
Describe the functions of a cell membrane.	It surrounds the cell and forms a boundary between the cytoplasm and the outside. The membrane is selectively permeable, so some substances can pass in and out of the cell.
Describe the functions of the cell wall.	It's a non-living material that surrounds the cell membrane of a plant cell. It's a tough material made mostly of cellulose and some other materials, and it also helps keep the plant cells shape. It is freely permeable.
Describe the functions of the chloroplast.	It absorbs the light energy for photosynthesis. It's green because of a green pigment called chlorophyll.
Describe the functions of the vacuole.	It's found in plant cells, and it contains cell sap, which is a store of dissolved sugars, mineral ions, and other solutes. Animal cells have small temporary vacuoles.
What are the differences between plant and animal cells?	- Plant cells have a cell wall, a permanent vacuole, and chloroplasts whereas animal cells don't. - Animal cells have a very irregular shape, whereas plant cells have a fixed shape.
What is the role of an enzyme?	Enzymes are biological catalysts in metabolic reactions. They're needed because temperatures inside organisms are low, so therefore the enzymes speed up the reactions.
What can affect the functioning of enzymes and why?	1) Temperatures - If the temperatures go above 37*C, then the enzyme will be denatured since proteins (what the enzymes are made of) are broken down by heat. 2) pH - Enzymes work best at around neutral (pH 7). If the pH increases or decreases, it changes the shape of the enzymes active site, so therefore the substrate will no longer fit as well into the active site.
Describe a simple controlled experiment to illustrate how enzyme activity can be affected by changes in temperature.	ACTUAL FLASHCARDS ON TESTS.
What is aerobic respiration and what are the word and chemical equations?	Aerobic respiration - Respiration using oxygen, is carried out in all animals and plants. Glucose + Oxygen -> carbon dioxide + water (+ energy) C6H12O6 + 6O2 -> 6CO2 + 6H2O (+ energy)
What is anaerobic respiration and what are the word and chemical equations?	Anaerobic Respiration - Respiration without using oxygen. Occurs when oxygen is short in supply, and releases less energy. Glucose -> ethanol + carbon dioxide (+ some energy) C6H12O6 -> 2C2H5OH +2CO2
Describe a simple experiment to demonstrate the production of carbon dioxide and heat from suitable living organisms.	ACTUAL FLASHCARDS ON TESTS.
Define diffusion and the factors that can affect the rate of diffusion	Diffusion - the net movement of particles from a region of high concentration to a region of low concentration, i.e down a concentration gradient. Factors that affect the rate of diffusion: - the concentration gradient - temperature - a large surface area to volume ratio
Define osmosis and factors that can affect the rate of osmosis.	Osmosis - the net movement of water from a dilute solution to a more concentrated solution across the partially permeable cell membrane. Factors that affect the rate of osmosis: - temperatures - pressure - surface area - concentration gradient - brightness
Define active transport and the factors that affect the rate of active transport.	Active transport - the movement of particles against a concentration gradient, using energy from respiration. Factors that affect the rate of active transport: - concentration of oxygen - concentration of glucose - temperature
Describe a simple experiment that demonstrates diffusion in agar jelly.	ACTUAL FLASHCARDS ON TEST.
What are the seven main systems in the human body?	- digestive system - respiratory system - circulatory system - excretory system - nervous system - endocrine system - reproductive system

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