OCR 21st Century Science Unit B4 Revision

Animal and Plant cellsRespiration and Photosynthesis

mitochondria contain enzymes for the reactions in aerobic respiration (in animals, plants and yeast)

cell membrane allows gases and water to pass in and out of the cell freely while presenting a barrier to other chemicals

nucleus or circular DNA in bacteria contains DNA which carries the genetic code for making enzymes used in the chemical reactions of respiration

cytoplasm where enzymes and proteins are made

chloroplasts contain chlorophyll and the enzymes for the reactions in photosynthesis

Animal and Plant Cells

Respiration

Animals and plants have many uses for the energy they generate from respiration:

1)To perform the life processes, such as moving, _____ etc

2)To build up body _______

3)To maintain a constant body ___________ (warm-blooded mammals only)

4)To build up sugars, ________ and other nutrients in plants

5)Active __________

Words – nitrates, tissue, proteins, transport, growing

Uses for respiration summary

1) Glucose (sugar) can be used to make long chains of insoluble starch…

Glucose molecules

Starch molecule

“Synthesis” means “making large molecules out of small ones”. Two examples:

2) Glucose can be combined with nitrates to make proteins (for growth)…Glucose

molecules Proteins

Synthesis

• all living things depend on chemical reactions within cells that require energy released by respiration

• Respiration is a series of chemical reactions that release energy by breaking down large food molecules in all living cells

Aerobic Respiration

glucose + oxygen

carbon dioxide + water (+ energy released)

C6H12O6 + 6O2 6CO2 + 6H2O

All living organisms have to move, _____, reproduce etc. Each of these life processes needs ENERGY. ___________ is the process our bodies use to produce this energy:

Glucose + oxygen water + carbon dioxide + ENERGY

The glucose we need comes from ______ and the oxygen from _________. Water and carbon dioxide are breathed out. The MAIN product of this equation is _________. Respiration happens in _________ in cells.

Words – breathing, energy, grow, respiration, food, mitochondria

Aerobic respiration summary

anaerobic respiration takes place in animal, plant and some microbial cells in conditions of low oxygen or absence of oxygen, to include:

Anaerobic Respiration

In Animal Cells:

glucose lactic acid (+ energy released)

In Yeast

glucose ethanol + carbon dioxide (+ energy released)

Happens in roots in waterlogged soil bacteria in puncture wounds human cells during vigorous exercise

Unlike aerobic respiration, anaerobic respiration is when energy is provided WITHOUT needing _________:

Glucose lactic acid + a bit of energy

This happens when the body can’t provide oxygen quick enough for __________ respiration to take place.

Anaerobic respiration produces energy much _______ than aerobic respiration but only produces 1/20th as much.

Anaerobic respiration can also take place in other low-oxygen conditions, such as plant roots in _________ soil or bacteria in ________ wounds.

Words – oxygen, aerobic, quicker, puncture, waterlogged

Anaerobic respiration summary

4)

2)

Mitochondria – contain enzymes for respiration reactions

Cell Membrane – controls what comes in and out

Cytoplasm - where enzymes are made

Nucleus – carries genetic info for making enzymes

1)

3)

In bacteria cells, this job is done by circular DNA

Respiration in cells