AQA Exam Answers
AQA Exam-style Questions
Cell activity
1. a) - A : nucleus - B : mitochondria
- C : ribosomes - D : plasmids b) The nucleus controls all activities within the cell. It also contains genetic materials used to create new cells.
c) Plasmids and genetic materials in cytoplasm
d) i 75 ii 28 iii 0.15
e) Protein can be used to build up cells as it is a structural component of every cells. It is also an enzyme as well.
f) There are no mitochondria in bacterial cells because they are single-cellular organisms, so they are very small and do not need energy.
2. a) Root hair cells are found at the root of plants. They help plants to absorb water and mineral ions from soil efficiently. Mesophyll cells are found in leaves. They carry out gas exchange and photosynthesis in plants. b) Root hair cells are adapted to increase the rate of diffusion of water and mineral ions from soil to be as quick as possible. The …show more content…
root hair increases the surface area for diffusion to take place. They have large permanent vacuoles that speed up the movement of water and mineral ions from the root to every part of the plant. Also, there is no chloroplast at all in the cells as they are undreground and so photosynthesis will not take place. Mesophyll cells contain lots of chloroplasts that trap the sun light for photosynthesis. They also have big air space and large surface area for efficient gas exchange to take place.\
a)
A stem cell from the plants in pot A is rigid but in pot B is shriveled. b) As the plant in pot A has been adequately watered, water is stored within the vacuole in the plants so that it keeps the cells rigid and supports the plants to stay up right. However, there is not enough water in the vacuole in pot B's plants to fill in the vacuole, so the cells cannot be supported and become shriveled.
4. a) Isotonic
b) 0.28
c) Water passes in and out of the cell by osmosis. This is the movement of water molecules from an area of high concentration to an area of lower concentration along a concentration gradient through a semi permiable membrane. According to the table, the cell in test 1 was bursted, this might be because too much water has entered the cell. This suggests that there is a higher concentration of water molecules outside than inside the cell. Therefore, water molecules move from the solution into the cell along the concentration gradient by osmosis. This solution is called hypotonic.
Cell division, Differentiation and Organisation
1. Chromosome is a structure carrying large number of genes.
Allele is a different form of one gene.
Gene is a section of genetic material coding for one characteristic.
Nucleus is the part of a cell that contains the genetic material.
Gamete is a cell with a single set of chromosomes.
2. a)
b) Daughter cells c)
3. a) iii, I, iv, v, ii b) cell, tissue, organ, organ system, organism
tissue organ cell organ system organism d) Flowers reproduce by sexual reproduction which means that gametes with a single set of chromosomes join together. This makes variaton in the offspring.
4. a) Stem cells are undifferentiated cells that can grow into any type of cells in the body unlike body cells that have already differentiated and cannot grow into other type of cells. Therefore, the doctor can use the growth of stem cells to consider the cells with a tissue-type match to cure the patient and also create a new life. b) Using stem cells become one of the most effective way to trat patients with genetic disorder and handicap. However, there are few problems that have been discussed a while ago. Firstly, using embryonic stem cells can cause a risk of cancer cells growth as they grow very rapidly so make them hard to control. Secondly, the study of stem cells has developed very slowly and the treatment is rather expensive. Lastly, there are some ethnic conflicts about using embryonic stem cells as religious people believe that the embryos are destroyed.
Carbohydrates, lipids, proteins and enzymes
a) I glucose ii glycerol iii amino acid iv fatty acid
b) i Enzymes are biological catalysts that help to speed up the chemical reactions without changing themselves.
ii The long chains of amino acid in the enzymes are folded and twisted into specific 3D shapes called the active site. This shape allows substrate with matching shape to fit into the enzyme and bind together. iii Denature iv Temperature and pH c) Protein is found in many tissues in the body such as muscles, as it is a main structural component that build up the tissues. Hormones are also protein which helps to control many body functions and take part in homeostasis such as, insulin hormones control the blood sugar level in the body. Antibodies that re part of immune system are also proteins. They help to protect the bpdy by engulf or digest foreign molecules entering it.
2. a) microorganisms b) i Protease ii amino acid c) i 14 minutes ii enzyme X iii Temperature and pH
value
3. a) The more concentrated the starch is, the darker colour the Iodine solution turns into.
b) After 20 minutes, carbohydrases A speeds up the digestion of starch into glucose, so the iodine solution does not change in colour.
c) Most enzymes work best at approximate 40c which is known as optimum temperature. If the temperature is too high, the enzymes can be denatured and stop working.
d) Fructose is much sweeter than glucose by the same amount of calories. Therefore, slimming foods use fructose by a smalller amount so that they have less calories but the same sweetness.
Cell activity
1. a) - A : nucleus - B : mitochondria
- C : ribosomes - D : plasmids b) The nucleus controls all activities within the cell. It also contains genetic materials used to create new cells.
c) Plasmids and genetic materials in cytoplasm
d) i 75 ii 28 iii 0.15
e) Protein can be used to build up cells as it is a structural component of every cells. It is also an enzyme as well.
f) There are no mitochondria in bacterial cells because they are single-cellular organisms, so they are very small and do not need energy.
2. a) Root hair cells are found at the root of plants. They help plants to absorb water and mineral ions from soil efficiently. Mesophyll cells are found in leaves. They carry out gas exchange and photosynthesis in plants. b) Root hair cells are adapted to increase the rate of diffusion of water and mineral ions from soil to be as quick as possible. The …show more content…
root hair increases the surface area for diffusion to take place. They have large permanent vacuoles that speed up the movement of water and mineral ions from the root to every part of the plant. Also, there is no chloroplast at all in the cells as they are undreground and so photosynthesis will not take place. Mesophyll cells contain lots of chloroplasts that trap the sun light for photosynthesis. They also have big air space and large surface area for efficient gas exchange to take place.\
a)
A stem cell from the plants in pot A is rigid but in pot B is shriveled. b) As the plant in pot A has been adequately watered, water is stored within the vacuole in the plants so that it keeps the cells rigid and supports the plants to stay up right. However, there is not enough water in the vacuole in pot B's plants to fill in the vacuole, so the cells cannot be supported and become shriveled.
4. a) Isotonic
b) 0.28
c) Water passes in and out of the cell by osmosis. This is the movement of water molecules from an area of high concentration to an area of lower concentration along a concentration gradient through a semi permiable membrane. According to the table, the cell in test 1 was bursted, this might be because too much water has entered the cell. This suggests that there is a higher concentration of water molecules outside than inside the cell. Therefore, water molecules move from the solution into the cell along the concentration gradient by osmosis. This solution is called hypotonic.
Cell division, Differentiation and Organisation
1. Chromosome is a structure carrying large number of genes.
Allele is a different form of one gene.
Gene is a section of genetic material coding for one characteristic.
Nucleus is the part of a cell that contains the genetic material.
Gamete is a cell with a single set of chromosomes.
2. a)
b) Daughter cells c)
3. a) iii, I, iv, v, ii b) cell, tissue, organ, organ system, organism
tissue organ cell organ system organism d) Flowers reproduce by sexual reproduction which means that gametes with a single set of chromosomes join together. This makes variaton in the offspring.
4. a) Stem cells are undifferentiated cells that can grow into any type of cells in the body unlike body cells that have already differentiated and cannot grow into other type of cells. Therefore, the doctor can use the growth of stem cells to consider the cells with a tissue-type match to cure the patient and also create a new life. b) Using stem cells become one of the most effective way to trat patients with genetic disorder and handicap. However, there are few problems that have been discussed a while ago. Firstly, using embryonic stem cells can cause a risk of cancer cells growth as they grow very rapidly so make them hard to control. Secondly, the study of stem cells has developed very slowly and the treatment is rather expensive. Lastly, there are some ethnic conflicts about using embryonic stem cells as religious people believe that the embryos are destroyed.
Carbohydrates, lipids, proteins and enzymes
a) I glucose ii glycerol iii amino acid iv fatty acid
b) i Enzymes are biological catalysts that help to speed up the chemical reactions without changing themselves.
ii The long chains of amino acid in the enzymes are folded and twisted into specific 3D shapes called the active site. This shape allows substrate with matching shape to fit into the enzyme and bind together. iii Denature iv Temperature and pH c) Protein is found in many tissues in the body such as muscles, as it is a main structural component that build up the tissues. Hormones are also protein which helps to control many body functions and take part in homeostasis such as, insulin hormones control the blood sugar level in the body. Antibodies that re part of immune system are also proteins. They help to protect the bpdy by engulf or digest foreign molecules entering it.
2. a) microorganisms b) i Protease ii amino acid c) i 14 minutes ii enzyme X iii Temperature and pH
value
3. a) The more concentrated the starch is, the darker colour the Iodine solution turns into.
b) After 20 minutes, carbohydrases A speeds up the digestion of starch into glucose, so the iodine solution does not change in colour.
c) Most enzymes work best at approximate 40c which is known as optimum temperature. If the temperature is too high, the enzymes can be denatured and stop working.
d) Fructose is much sweeter than glucose by the same amount of calories. Therefore, slimming foods use fructose by a smalller amount so that they have less calories but the same sweetness.