Biology GCSE Revision Questions and Correct Answers (100% COMPLETE ANSWERS) ALREADY GRADED A+ 100% satisfaction guarantee with complete solutions, (Latest update) .pdf

Biology GCSE n




1. What are the parts of an animal (and plant) cell?: NucleusCytoplasm
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Cell membranen n


Mitochondria


2. What are parts of a plant cell?: Rigid cell wall
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Large vacuole n n




Chloroplasts

(nucleus, cytoplasm, cell membrane and mitochondria)
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3. What does the nucleus do?: Contains DNA that controls what the cell does
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4. What does the cytoplasm do?: Its a gel-
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like substance where most of thechemical reactions happpen
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5. What does the cell membrane do?: Holds the cell together and controls whatgoe
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s in and out
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6. What does the mitochondria do?: This is where most of the reactions for resp
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iration take place. Respiration releases energy that the cell needs to work.
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7. What does the rigid cell wall do?: It is made up of cellulose and it gives supportfor t
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he cell
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8. What does the large vacuole do?: Contains cell sap, a weak solution of sugarand s
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,alts

9. What do chloroplasts do?: This is where photosynthesis occurs. They containa gre
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en substance called chlorophyll.
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10. What are the features of a bacteria cell?: Chromosomal DNAPla
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smids

Flagellum n




Cell wall
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11. What is chromosomal DNA?: Chromosomal DNA controls the cells activitiesand
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replication. It floats free in the cytoplasm.
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12. What are plasmids?: Plasmids are small loops of extra DNA that aren't part ofthe c
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hromosome. Plasmids contain genes for things like drug resistance and can bepassed be
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tween bacteria.
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13. What is the flagellum?: The flagellum is a long, hair-
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like structure that rotatesto make the bacterium move.
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14. What does the cell wall do?: Support the cell
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15. What is magnification?: How much bigger the image is that the specimen
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16. How do you work out magnification?: length of image / length of specimen
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17. What is the difference between light microscopes and electron micro-
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scopes?: Light microscopes let us see things like the nuclei, chloroplasts and mitoch
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,ondria. Electron microscopes let us see much smaller things in more detail
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, like the internal structure of mitochondria and chloroplasts and even tinier things likepl
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asmids.

18. What is DNA?: DNA is the complex chemical that carries genetic information.DNA
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n is found in chromosomes which are found in the nucleus of most cells.
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19. What is the structure of DNA? (6marker): - n n n n n n n




A DNA molecule has two strandscoiled together in the shape of a double helix.
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-

The two strands are hold together by chemicals called bases. The four bases areadenine
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thymine, guanine and cytosine. n n n




-The bases are paired, and they always pair up in the same way; A-T and C-
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G. Thisis called base pairing.
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-The base pairs are joined together by weak hydrogen bonds.
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20. What is a gene?: A gene is a short piece of DNA that codes for a specific protein.You ha
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ve genes for hair structure, eye colour enzymes and every other protein in your body.
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21. Who discovered the structure of DNA?: - n n n n n n




Rosalind Franklin and Maurice Wilkins worked out DNA had a helical structure by dir
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ecting beams of X-rays ontocrystallised DNA and looking at the patterns of x-
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rays formed as they bounced off.
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