Higher Human Biology Unit 1 Human Cells Homework Booklet · Higher Human Biology Unit 1 – Human Cells Homework Booklet . D. A 4. The cell shown below is magnified six hundred times

Higher Human Biology

Unit 1 – Human Cells

Homework Booklet

Sub-Topic 1: Division and Differentiation in Human Cells

Homework 1 Total 7 1. Which line in the table below describes correctly cell division in a specific cell type

Cell Type Type of cell division

Chromosome number in cells

produced

A somatic meiosis diploid

B somatic meiosis haploid

C germline mitosis haploid

D germline mitosis diploid

2. Which of the following statements is TRUE?

A. Blood cells and muscle cells are undifferentiated germline cells

B. Blood cells and muscle cells are differentiated germline cells

C. Blood cells and muscle cells are undifferentiated somatic cells

D. Blood cells and muscle cells are differentiated somatic cells

3. Which of the following statements regarding stem cells is TRUE?

A Stem cells are specialised cells that continue to divide.

B Stem cells cannot differentiate into specialised cells

C Stem cells are unspecialised cells that can differentiate into specialised cells.

D None of the above

4. The cell shown below is magnified six hundred times. What is the actual size of the cell?

A 1080 μm

B 108 μm

C 30 μm

D 3 μm

18mm

5. The diagram below shows some stages in the development of blood cells and nerve cells.

a) What are stem cells? (1) b) State the location of the tissue stem cells which develop into blood cells.

(1)

c) Describe what is meant by the term differentiation. (1)

Sub-Topic 1: Division and Differentiation in Human Cells

Homework 2 Total 10

1. Which of the following is not a use of stem cells?

A Skin grafts B Drug testing C IVF treatment D Bone marrow transplant

2. Which of the following statements about cancer cells is TRUE?

A Cancer cells respond to regulatory signals

B Cancer cells cannot spread through the body

C Cancer cells cannot divide excessively

D Cancer cells can form secondary tumours

3. Cancer cells can divide excessively to produce a mass of abnormal cells known as a tumour.

A tumour cell can double every 40 minutes. If one tumour cell starts to divide how many tumour cells will be present after 12 hours?

A 720 B 32768 C 131072

D 262144

4. Both embryonic stem cells and tissue stem cells are used in medical research. Give one reason why embryonic stem cells are potentially more useful than tissue stem

cells. (1)

5 a) Stem cells can be used in research and therapeutics (branch of medicine relating to the treatment of disease) because stem cells are able to develop into different types of cells. Explain why stem cells are able to develop into different types of cells. (1)

b) List 3 therapeutic uses of stem cells. (3)

6. Tumours can be found in patients suffering from cancer.

a) Describe what a tumour is: (1)

b) Describe how a secondary tumour develops: (1)

Sub-Topic 2: Structure and Function of DNA

Homework 1 Total 12

1. A DNA molecule consists of 4000 nucleotides of which 20% contain the base adenine.

How many of the nucleotides in this DNA molecule will contain guanine?

A 800 B 1000 C 1200

D 1600

2. A fragment of DNA was found to have 120 guanine bases and 60 adenine bases. What is the total number of sugar molecules in this fragment?

A 60 B 90 C 180 D 360

3. If ten percent of the bases in a molecule of DNA are adenine, what is the ratio of adenine to guanine in the same molecule?

A 1:1 B 1:2

C 1:3

D 1:4

4. DNA controls the activities of a cell by coding for the production of A proteins B carbohydrates C amino acids

D bases

5. A DNA nucleotide could be formed from a molecule of phosphate together with A Ribose sugar and guanine

B Ribose sugar and uracil

C Deoxyribose sugar and guanine

D Deoxyribose sugar and uracil

6. If a DNA molecule contains 8000 nucleotides of which 20% are adenine, then the number of guanine nucleotides present is:

A 1600

B 2000

C 2400

D 3200

7. The table below refers to the mass of DNA in certain human body cells.

Cell type Mass of DNA in cell (x10-12g)

liver 6.6

Lung 6.6

P 3.3

Q 0.0

Which of the following is most likely to identify correctly cell types P and Q?

P Q

A Kidney cell Sperm cell

B Sperm cell Mature red blood cell

C Mature red blood cell Sperm cell

D Nerve cell Mature red blood cell

8. How many adenine molecules are present in a DNA molecule of 4000 bases, if 20% of the base molecules are cytosine?

A 400 B 600 C 800

D 1200

9. Thirty percent of bases in a DNA molecule are adenine. The percentage of cytosine bases in the same molecule is

A 20%

B 30%

C 40%

D 70%

10. If the mass of DNA in a human liver cell is 6.6 x 10-12g, the mass of DNA in a human sperm is likely to be

A 3.3 x 10-6g

B 3.3 x 10-12g

C 6.6 x 10-6g

D 6.6 x 10-12g

11. The two components which make up the backbone of each DNA strand are

A Ribose and phosphate group C Deoxyribose and base pairs

B Deoxyribose and phosphate group D Phosphate group and thymine

12. Which of the following statements about the structure of DNA is TRUE?

A In DNA the base pairs are held together by peptide bonds.

B Fragments of DNA are joined together by ligase

C Fragments of DNA are joined together by polymerase

D DNA contains the bases represented by the letters A, U, C and G.


Homework 2 Total 15 1. The function of tRNA in cell metabolism is to A transport amino acids to be used in synthesis B carry codons to the ribosomes C synthesise proteins

D transcribe the DNA code

2. The following information refers to protein synthesis.

tRNA anticodon amino acid carried by tRNA

G U G Histidine (his)

C G U Alanine (ala)

G C A Arginine (arg)

A U G Tyrosine (tyr)

U A C Methionine (met)

U G U Threonine (thr)

What order of amino acids would be synthesised from the base sequence of DNA shown? Base sequence of DNA

C G T T A C G T G

A arg - tyr - his B ala - met - his C ala - tyr - his

D arg - tyr - thr

3. The table below contains statements which may be TRUE or FALSE with regard to DNA replication and mRNA synthesis.

Which line in the table is correct?

Statement DNA Replication mRNA synthesis

A Occurs in the nucleus

TRUE FALSE

B Involved in protein synthesis

TRUE

TRUE

C Requires free nucleotides

TRUE

FALSE

D Involves specific base pairing

TRUE

TRUE

4. The diagram represents part of a molecule of DNA on which a molecule of RNA is being synthesised.

What does component X represent?

A Ribose sugar B Deoxyribose sugar

C Phosphate

D Ribose phosphate

Homework 2 (continued)

6. The base sequence of a short piece of DNA is shown below

During replication, an inversion mutation occurred on the complementary strand synthesised on this piece of DNA.

7. Which of the following statements about DNA replication is correct?

A Polymerase adds nucleotides to the 3’ end of a DNA strand B Polymerase adds nucleotides to the 5’ end of a DNA strand C Ligase adds nucleotides to the 3’ end of a DNA strand D Ligase adds nucleotides to the 5’ end of a DNA Strand

8. A section of DNA has the following base sequence

Identify the anti-codons of the three tRNA molecules which would align with the mRNA molecule transcribed from this section of DNA. A AAU CGC UUC B AAT CGC TTC C TTA GCG AAG

D UUA GCG AAG


9. Which of the following diagrams correctly represents part of a DNA molecule? The letters A, T, U, C and G represent bases.

10. Which of the following lines regarding DNA amplification is TRUE?

Melting Annealing Extending

A. Heating the DNA to separate the strands

Primers bind at two ends of the region to be amplified

Complementary strands of target DNA are made

B. Complementary strands of target DNA are made

Heating the DNA to separate the strands


C. Primers bind at two ends of the region to be amplified

Heating the DNA to separate the strands


D. Heating the DNA to separate the strands



11. How many cycles have been completed if 128 molecules of DNA were produced from one double DNA helix?

A. 5 B. 6 C. 7 D. 8

12. The mRNA codon for the amino acid theronine is ACU. What is the corresponding anti-codon?

A. ACT B. UCT C. UGA D. TGA

13. (a) State the mRNA codon which would be formed from the triplet of DNA bases shown. 1

(b) Apart from nucleotides, name another molecule needed for the

synthesis of mRNA. 1

14. The diagram above illustrates the two main stages of protein synthesis.

Describe three differences between DNA and mRNA. 2


Homework 3 Total 15

1 (a). Name bases 3, 8 and 11. 2

(b) Where in the cytoplasm does stage 2 take place 1

(c) Name molecules X and Y. 1

(d) The newly synthesised protein may be secreted from the cell.

(i) Name the cell structure where the protein would be found just before it enters a secretory vesicle. 1

(ii) Describe what happens to the protein while it is in this cell structure. 1

(a) In which part of the cell in mRNA formed? 1 (b) Copy the diagram above and then, on your diagram, complete the mRNA molecule

by filling in the correct base sequence. 1 (c) How many amino acids are coded for by this section of mRNA? 1

3. (a) The diagram below shows a section of a messenger RNA (mRNA) molecule.

(i) Name the sugar that is present in mRNA 1 (ii) Which base found in mRNA is not shown in the diagram?

1

(iii) Name two parts of a cell where mRNA is found. 1

(b) DNA templates are used to produce mRNA molecules.

(i) Copy the table below and insert the names of the DNA bases which pair with the RNA bases shown.

DNA base RNA base

adenine

uracil

guanine

1

2. The diagram shows part of an mRNA molecule being formed on a strand of DNA.


Homework 4 Total 23

1. The formation of a mRNA strand on a section of a chromosome is shown in the diagram below.

a) Give the names of bases 1, 2 and 3. 1

b) The mRNA strand is constructed from free nucleotides. Name the two molecules which combine with a base to form a mRNA nucleotide. 1

c) Once completed, the mRNA strand moves into the cytoplasm. What is its destination? 1

d) Explain why the formation of mRNA strands is essential to cell metabolism. 2

2. The diagram shows the synthesis of a peptide chain.

(a) Name bond X and molecule Y. 2

(b) What term is used to describe the triplet code on the tRNA molecules? 1 (c) Give the abbreviated names of the next four amino acids which will be attached to

complete the peptide chain. Iso _________ _________ ________ _______ ___________ 1 (d) What sequence of bases on a DNA molecule will code for the amino acid labelled thr?1 (e) Amino acids are added to the peptide chain at the rate of 15 per second. How long will it take for the complete synthesis of the peptide shown in the diagram above?

1

3. The diagram below shows a section through a nucleus and associated cell structures.

a) (i) Name organelle X. 1 (ii) What type of substance is manufactured by organelle X? 1 (iii) Give an example of such a substance 1

b) (i) The structure labelled Y is composed of sheets of membranes.

What name is given to this structure? 1

(ii) Structure Y can transport substances to another organelle within the cell. Give an example of such an organelle and state its function. 2

c) Why is it necessary to have pores in the nuclear membrane? 1

4. The diagram below shows one gene within a chromosome.

non coding region of the gene coding region of the gene

(a) State what non-coding regions of a gene are called. 1

(b) Explain why it is important that non-coding regions are removed from the primary transcript of this gene before translation. 1

(c) The diagram below shows part of one coding region of the mRNA from this gene.

How many different types of amino acid are coded for by this region of the mRNA strand? 1

(d) Describe two ways in which the structure of a molecule of mRNA differs from that of DNA. 2

Homework 5

2. A substitution mutation results in a triplet of bases TTC being changed to TCC. The amino acid lysine is coded for by TTC and arginine by TCC.

A arginine replaces lysine throughout the protein B arginine replaces lysine at one position in the protein C lysine replaces arginine throughout the protein D lysine replaces arginine at one position in the protein

1. Non-disjunction can be described as

A a metabolic disorder B a type of antisocial behaviour C a condition resulting in memory loss

D a form of chromosome mutation

3. Which type of gene mutation occurs when a codon for an amino acid is replaced by a stop codon?

A Nonsense

B Missense

C Frameshift

D Splice-site

4. Individuals with Cri-du-chat syndrome have a shortened chromosome 5. No other chromosomes are affected Which type of mutation causes Cri-du-chat syndrome? A Deletion

B Insertion

C Duplication

D Translocation

5. Phenylketonuria (PKU) is a metabolic disorder which can be lethal in childhood. It is caused by an inability to make enzyme X, shown in the metabolic pathway below.

Which substance would have to be removed from the diet for someone who has this disorder?

A Phenylalanine

B Enzyme X

C Tyrosine

D Melanin

6., In Duchenne Muscular Dystrophy (DMD) one amino acid codon is substituted with a stop codon.

A. Missense B. nonsense C. frameshift D. splice-site

7. In cystic fibrosis (CF) one base pair is deleted. This is an example of

A. Missense B. nonsense C. frameshift D. splice-site

Sub-Topic 2: Structure and Function of DNA Homework 6 Total 19

1. During the polymerase chain reaction (PCR) samples of DNA are repeatedly heated and cooled. Why are the samples cooled?

A To denature DNA polymerase B To slow the reaction down C To allow primers to bind to target sequences D To separate the DNA strands 2. What is the function of a DNA probe?

A To replicate a particular region of DNA B To join fragments of DNA together C To remove non-coding sections of DNA D To detect the presence of specific DNA sequences

3. The diagram below shows the results of a paternity test. It compares DNA samples from five individuals.

Woman S is the mother of child X and child Y. Men P and Q are possible fathers of

these children.

Which of the following conclusions can be drawn from these results?

A Man P could be the father of child X B Man P could be the father of child Y C Man Q could be the father of child X

D Man Q could be the father of child Y

4. The graph below show the mass of DNA present as gamete mother cells develop into sperm cells during meiosis in the testes. P and Q represent cells at intermediate stages in this process.

(a) Explain why the mass of DNA changes between

(i) the gamete mother cells and cell type P 1 (ii) cell types P and Q 1 (b) Some diseases are caused when cells in the body produce a harmful protein. Recent

research has led to the development of antisense drugs to treat such diseases. These drugs carry a short strand of RNA nucleotides designed to attach to a small part of the mRNA molecule that codes for the harmful protein.

(i) Suggest how these drugs may prevent the production of a harmful protein. 1

(ii) Antisense drugs can be used to treat autoimmune diseases.

Describe what is meant by an autoimmune disease. 1


5. Many inherited disorders are caused by inborn errors of metabolism.

(a) (i) What causes disorders that lead to inborn errors of metabolism? 1

(ii) How do these inherited disorders affect metabolic pathways? 1

(b) Phenylketonuria (PKU) is an example of an inherited disorder.

One metabolic pathway affected by PKU is shown below.

(i) Describe how PKU affects the metabolic pathway shown above. 1

(ii) With reference to the metabolic pathway shown, explain why PKU affects the nervous system. 2

(c) What term describes the testing of newborn babies for inherited disorders? such as PKU? 1

6. The diagram below shows part of a metabolic pathway. Each stage is controlled by an enzyme.

Phenylketonuria (PKU) is caused by a mutation of the gene required to make enzyme

A 1 B 2 C 3

D 4

Sub-Topic 3: Cell Metabolism

Homework 1 Total 12 1. The diagram below shows a metabolic pathway that is controlled by end product

inhibition.

For Substance 4 to bring about end product inhibition, with which of the following would it interact. A. Enzyme 1

B. Enzyme 3

C. Substance 1

D. Substance 3

2. The graph shows the effect of substrate concentration on the rate of an enzyme-catalysed reaction.

At what substrate concentration is the reaction rate equal to 75% of the maximum rate? A. 6 units B. 8 units C. 12 units D. 18 units


3. The graph shows the effect of substrate concentration on the rate of an enzyme-controlled reaction.

The graph levels out between points X and Y because the

A. enzyme is denatured

B. active sites are saturated with substrate

C. enzyme is inhibited

D. enzyme is activated.

4. The cell organelle shown below is magnified ten thousand times.

What is the actual size of the organelle?

A. 1.04μm

B. 0.4 μm C. 4 μm D. 40 μm

Competitive Non-competitive Feedback inhibition

A. Binds to active site of the enzyme

Changes shape of active site of enzyme

End product binds to an enzyme that catalyses a reaction early in the pathway

B. End product binds to an enzyme that catalyses a reaction early in the pathway


Binds to active site of the enzyme

C. Changes shape of active site of enzyme

Binds to active site of the enzyme


D. Binds to active site of the enzyme




5. The following table gives information on the control of metabolic pathways using inhibitors.

Which line in the table is CORRECT?

Type of inhibitor

6. The diagram below represents a reaction catalysed by an enzyme in the cytochrome system.


(a) (i) What name is given to the part of the enzyme where this reaction occurs? 1

(ii) In which organelle would this reaction take place? 1

(iii) Name the product of this reaction. 1

(b) Cyanide is a poison which inhibits this enzyme.

Suggest how cyanide is able to do this. 1

(c) Why do many enzyme-catalysed reactions require the presence of vitamins or

minerals? 1

d) The graph shows the effect of increasing substrate concentration on the rate of this reaction.

(i) Explain why the graph levels out at high substrate concentration. 1 (ii) Assuming that the enzyme is operating at its optimum pH and temperature, suggest how the rate of reaction could be increased at high substrate

concentrations. 1


Homework 2 Total 19 1. During which of the following chemical conversions is ATP produced? A. Amino acids Protein

B. Glucose Pyruvic acid

C. Haemoglobin oxyhaemoglobin

D. Nucleotides mRNA

2. The following statements relate to respiration and the mitochondrion. 1 Glycolysis takes place in the mitochondrion. 2 The mitochondrion has two membranes. 3 The rate of respiration is affected by temperature. Which of the above statements are correct?

A. 1 and 2 B. 1 and 3 C. 2 and 3 D. All of them

3. The diagram below shows energy transfer within a cell.

Which line in the table below identified correctly compounds X and Y?

X Y

A glucose ATP

B glucose ADP

C ADP ATP

D ATP glucose

Question 4 and 5 refer to the chart below. The following chart shows stages in the complete breakdown of glucose in aerobic

respiration.

4. At which stage or stages is hydrogen released to be picked up by hydrogen acceptors?

A. Stages X, Y and Z B. Stages X and Y only C. Stages Y and Z only D. Stage Z only

6. The diagram shows part of a liver cell with four parts labelled. In which part is most ATP produced?

5. At which stage, or stages, is carbon dioxide released?

A. Stages X and Z B. Stages X and Y C. Stages Y and Z D. Stage Z only.

8. In respiration, the sequence of reactions resulting in the conversion of glucose to pyruvic acid is called

A. the Krebs cycle

B. the citric acid cycle

C. glycolysis

D. the cytochrome chain.

9. Which of the following often act as a co-enzyme? A. Lipids

B. Polysaccharides

C. Hormones

D. Vitamins

10. The diagram below represents stages in tissue respiration.

Which box represents ATP?

11. A piece of muscle was cut into three strips X, Y and Z and treated as described in the table.

Their final lengths were then measured.

Muscle strip

Solution added to muscle

Muscle length (mm) Start

Muscle length (mm) after 10 minutes

X 1 % glucose 50 50

Y 1 % ATP 50 45

Z 1% ATP boiled and cooled

50 46

From the data it may be deducted that

A. ATP is not an enzyme

B. muscles contain many mitochondria

C. muscles synthesise ATP in the absence of glucose

D. muscles do not use glucose as a source of energy.

12. The diagram below shows two stages of respiration

(a) (i) Identify stages A and B. 2

(ii) Name Substance X. 1

(b) During Stage A, glucose is converted to pyruvate.

Name the molecule that provides phosphate for this conversion. 1

(c) The conversion of citrate to substance X in Stage B involves several reactions.

Name two molecules, apart from NADH, which are produced during these

reactions. 1

(d) Phosphofructokinase is an enzyme involved in Stage A.

The presence of excess citrate inhibits this enzyme.

Explain why this is important in the conservation of resources in the cell. 1

(e) NADH is also produced during Stage A.

Explain the role of NADH when cells do not get sufficient oxygen for aerobic

respiration. 2


Homework 3 Total 14

1. In respiration, the sequence of reactions resulting in the conversion of glucose to pyruvic acid is called

A. the Krebs cycle

B. the citric acid cycle

C. glycolysis

D. the cytochrome chain.

2. Which of the stages in aerobic respiration produces the most ATP? A. Glycolysis B. Citric Acid C. Krebs Cycle D. Electron Transport (Cytochrome system)

3. The diagram below shows some of the reactions which occur during aerobic respiration

Continued on next page

3. (continued) (a) Copy and complete the table by naming stages A, B and C and indicating their

exact location within cell.

Stage Name Location

A

B

C

3 (b) A glucose molecule contains 6 carbon atoms

How may carbon atoms are found in the flowing molecules?

Pyruvic acid Citric acid 1

(c) Copy and complete the following sentences by naming molecules R and S and describing their function with respect to stage C.

R is ________________________________and its function is_________________ __________________________________________________________________ __________________________________________________________________ S is _______________________________and its function is __________________ ___________________________________________________________________

_________________________________________________________________ 2


4. The diagram below shows three stages that occur during aerobic respiration.

(a) Name each stage. 2 b) i) Arrows 1 and 2 represent the transfer of molecules from one stage to another. Copy and complete the table to identify these molecules.

Arrow Name of molecule

1

2

2 (ii) Name the two metabolic products of stage Z. 1

(c) The diagram below shows a mitochondrion from a skin cell.

Describe how the structure of mitochondrion from an active muscle cell would differ from the one shown. Give a reason for your answer.

Structural difference 1 Reason 1

5. The table below contains three statements about two stages of cellular respiration.

Copy and complete the table to indicate whether the statements are True (T) or False (F) for each stage.

Statement

Glycolysis Cytochrome System

Occurs in the mitochondrion

T

Releases carbon dioxide

F

Uses oxygen

2

Stages of Respiration


Homework 4 Total 21

1. In respiration, the products of the cytochrome system are

A. hydrogen and carbon dioxide B. water and ATP C. oxygen and ADP D. pyruvic acid and water

3. Which line in the table has pairs of statements which are true with regard to aerobic respiration and anaerobic respiration in human muscle tissue?

Aerobic respiration Anaerobic respiration

A There is a net gain of ATP

Carbon dioxide is not produced

B There is a net gain of ATP Oxygen is used up

C Carbon dioxide is evolved There is a net loss of ATP

D Lactic acid is formed Ethanol is formed

2. Which of the following statements about the role of dehydrogenase enzyme in respiration is TRUE?

A. Dehydrogenase enzymes remove oxygen ions from a substrate

B. Dehydrogenase enzymes add hydrogen ions to a substrate

C. Dehydrogenase enzymes remove hydrogen ions from a substrate

D. Dehydrogenase enzymes add oxygen ions to a substrate

4. The diagram below represents two stages in the chemistry of respiration in a cell which is respiring aerobically

(a) Name the 3-carbon compound and the 6-carbon compound. 2 (b) Copy the diagram and draw a line across it to indicate where this series of reactions would stop if oxygen were not available. 1

(c)State the precise location of the Krebs cycle within the cell 1

(d) Copy and complete the table below to name product X and to describe what happens to each of the products.

Product Fate of product

X _________________

Hydrogen

2

5. The diagram shows the role of ATP in cell metabolism.

(a) Copy and complete the diagram by entering the names of the appropriate substances. 3

(b) (i) Name one stage of pathway X and state where it occurs in the cell. 1

(ii) Name the organelle where process Y occurs. 1 (c) Describe two ways in which the diagram would be different under anaerobic

conditions. 2 (d) Name a respiratory substrate other than glucose. 1

6. The diagram below summarises anaerobic respiration in a muscle cell.

(a) Name substance X 1

(b) Which substance would need to be present for pathway Y to occur? 1 (c) Why is anaerobic respiration considered to be a less efficient process than aerobic respiration? 1 (d) Glucose is not stored in muscle cells.

Name the carbohydrate which is stored in muscle cells. 1


Homework 5 Total 18

1. Which of the following is an insoluble polysaccharide?

A. Glycogen

B. Glucose

C. Sucrose

D. Maltose

2. The graph below shows changes which occur in the masses of protein, fat and carbohydrate in a person’s body during seven weeks without food.

The person’s starting weight was 60kg. Predict their weight after two weeks without food.

A. 57kg B. 54kg C. 50kg D. 43kg

3. Lysosomes are abundant in

A enzyme secreting cells B muscle cells C cells involved in protein synthesis

D phagocytic cells

4. The key below can be used to identify carbohydrates. 1. Soluble ………………………….2 Insoluble ………………………..glycogen 2. Benedict’s test positive ……….3 Benedict’s test negative ………sucrose 3. Barfoed’s test positive ………..4 Barfoed’s test negative ………..lactose 4. Clinistix test positive …………..glucose Clinistix test negative ………….fructose Which line in the table of results below is not in agreement with the information

contained in the key?

Carbohydrate Benedict’s test

Barfoed’s test

Clinistix test

A lactose positive negative not tested

B glucose positive negative positive

C fructose positive positive negative

D sucrose negative not tested

not tested

5. The Golgi apparatus is involved in the packaging of

A. ribosomes

B. monosaccharides

C. RNA

D. enzymes.

6. Which of the following statements is CORRECT?

A. Slow twitch muscle fibres are good for long distance running because they have fewer mitochondria and greater blood supply than fast twitch muscle fibres.

B. Slow twitch muscle fibres are good for long distance running because they have more

mitochondria and lesser blood supply than fast twitch muscle fibres. C. Slow twitch muscle fibres are good for long distance running because they have more

mitochondria and greater blood supply than fast twitch muscle fibres D. Slow twitch muscle fibres are good for sprinting because they have more mitochondria

and greater blood supply than fast twitch muscle fibres.

7. Under normal circumstances carbohydrate is the main respiratory substrate.

In each of the following extreme situations, state the alternative respiratory substrate and explain why the body has to use it.

Situation

Respiratory substrate Explanation

Prolonged starvation

Towards the end of a marathon race

2

2

8. Which of the following equations describes correctly the role of creatine phosphate?

A. ADP + phosphate + creatine creatine phosphate + ATP

B. creatine phosphate + ADP ATP + creatine C. creatine phosphate + ATP ADP + phosphate + creatine D. ATP + phosphate creatine phosphate + ADP

9. The graph below shows the changes which occur in a body’s food stores during four weeks of food deprivation.

Which of the following conclusions can be drawn from the graph? A The glycogen food store decreases at the fastest rate during week one. B Between weeks three and four the body gains most energy from protein. C Each food store decreases at a constant rate during week one. D Between weeks one and four the body only gains energy from lipid and protein.

10. The diagram below shows the metabolism of three energy sources in a cell.

(a) Name X, Y and Z 2 (b) What term describes the breakdown of carbohydrate into pyruvic acid during respiration? 1 (c) Describe what happens to acetyl CoA after it enters the Krebs Cycle. 1 (d) Under what circumstances would the body gain most of its energy from

proteins? 1 (e) Carbohydrate is stored in the body as a polysaccharide. Name this polysaccharide and state where it is stored. 1

Chemical test

11. The table below shows the results of chemical tests on five carboydrates.

Carbohydrate

Iodine solution Benedict’s solution

Barfoeds’s regent

Clinistix strip

Starch Turns blue-black

Stays blue Stays blue Stays pink

Sucrose Stays brown

Stays blue Stays blue Stays pink

Lactose Stays brown

Turns orange Stays blue Stays pink

Fructose Stays brown

Turns orange Turns orange Stays pink

Glucose Stays brown

Turns orange Turns orange Turns purple

What is the minimum number of tests that would need to be carried out to identify an unknown carbohydrate as lactose?

A. One B. Two C. Three D. Four

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Higher Human Biology Unit 1 Human Cells Homework Booklet · Higher Human Biology Unit 1 – Human Cells Homework Booklet . D. A 4. The cell shown below is magnified six hundred times