Cellular Biology - Answers
Exam Review – Dec.2011
Review the following topics
Cell theory, types of cells, microscopesPlant and Animal Cells, parts and their functions
Using a Microscope, microscope parts and functions
Parts of the Cell Membrane, fluid Mosaic Model
Movement of Particles Through the Cell Membrane
Diffusion, osmosis, 3 types of solutions, factors affecting passive transport
Carbohydrates
Lipids
Proteins
Enzymes, Factors Affecting Enzyme Activity
Cellular Respiration (aerobic and anaerobic )
Modified True/False
Indicate whether the sentence or statement is true or false. If false, change the identified word or phrase to make the sentence or statement true.
__F__ 1. Animals store carbohydrates as starch. ____glycogen______
__T__ 2. Enzymes speed up chemical reactions. ______
__T__ 3. The attachment of the substrate to the enzyme’s active site creates the enzyme-substrate complex. ______
__T__ 4. The active site is the location where a substrate binds to an enzyme. ______
__F__ 5. The overall process of aerobic respiration produces thirty molecules of ATP. _____36______
__F__ 6. Anaerobic respiration can produce ATP even if glucose is not present. _____oxygen______
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
__a__ 1. What statement about saturated fatty acids is correct?
a. / they contain only single bonds / c. / they are liquids at room temperatureb. / they contain triple bonds / d. / they contain several double bonds
__b__ 2. The building block (monomer) of proteins is
a. / Glucose / c. / Glycerol + 3 fatty acid chainsb. / Amino acids / d. / nucleotides
__b_ 3. Of the 20 amino acids found in the human body, how many are considered essential?
a. / 2 / c. / 12b. / 8 / d. / 0
__c__ 4. In brewing, baking, and winemaking, the enzymes found in yeast cells convert glucose to
a. / Carbon dioxide and water / c. / alcohol and carbon dioxideb. / Lactic acid / d. / pyruvate
__b__ 5. ATP stands for
a. / adenine triglyceride phosphotase / c. / adenosine tetraphosphateb. / adenosine triphosphate / d. / additional temperature promoter
__a__ 6. Which of the following is the correct equation for aerobic cellular respiration?
a. / C6H12O6 + 6 O2 ® 6 CO2 + 6 H2O+ 36 ATPb. / 2 C3H6O3 + 6 O2 ® 6 CO2 + 6 H2O+ 34 ATP
c. / C6H12O6 ® 2 C3H6O3
d. / C6H12O6 ® 2 C2H5OH + 2 CO2
__b__ 7. Which of the following is the correct equation for glycolysis?
a. / C6H12O6 + 6 O2 ® 6 CO2 + 6 H2O+ 36 ATPb. / C6H12O6 ® 2 C3H6O3
c. / 2 C3H6O3 + 6 O2 ® 6 CO2 + 6 H2O+ 34 ATP
d. / C6H12O6 ® 2 C2H5OH + 2 CO2
_ a___ 8. From one glucose molecule, how many molecules of ATP are created during lactic acid fermentation?
a. / 2 / c. / 36b. / 34 / d. / 0
9. The movement of solutes across a cell membrane from an area of low concentration to high concentration is called
(a) Passive Transport
(b) Active transport
(c) Brownian motion
(d) Diffusion
(e) Osmosis
10. If a cell is placed in a hypertonic environment,
(a) There is a higher concentration of water outside the cell than inside the cell
(b) There will be a net movement of water into the cell causing it to swell
(c) There is a higher concentration of water inside the cell than outside the cell
(d) The concentrations of water inside and outside the cell are equal
(e) (a) and (b)
11. If skittles are placed in a beaker of water, the food colouring will disperse until all of the water becomes coloured. This is the result of
(a) Active transport
(b) Diffusion
(c) Osmosis
(d) Facilitated diffusion
(e) None of the above
12. The site of protein synthesis in the cell
a. Ribosomes
b. Mitochondrion
c. Vacuoles
d. Lysosomes
e. Microtubules
13. Carbohydrates are polymers of . . .
(a) glucose
(b) amino acids
(c) lipids
(d) nucleotides
(e) starch
14. What is osmosis?
(a) a type of reverse diffusion
(b) the movement of particles through a semi-permeable membrane
(c) the movement of water through a semi-permeable membrane
(d) the movement of any substance through a selectively permeable membrane
(e) the movement of water particles without need for a membrane
15. Most body cells are continually being replaced as they wear out. The organelle responsible for breaking down worn-out cells is the
(a) cell membrane
(b) vacuole
(c) vesicle
(d) endoplasmic reticulum
(e) lysosome
16. A plant vacuole serves as a storage space for
(a) water
(b) sugars
(c) minerals
(d) waste
(e) all of the above
17. Which of the following statements about the cell membrane is correct?
(a) Both ends of the phospholipid are hydrophilic.
(b) Both ends of the phospholipid are hydrophobic.
(c) There is one type of protein embedded in the bilayer.
(d) A variety of proteins are embedded in the bilayer.
(e) None of these statements is correct.
Matching
Match each item related to carbohydrates to the correct statement listed below.
a. / Monosaccharide / d. / Glycogenb. / Disaccharide / e. / Starch
c. / polysaccharide / f. / cellulose
_a___ 1. simplest carbohydrate, consisting of a single sugar
_e___ 2. A molecule that stores energy in plants.
_b___ 3. two monosaccharides linked together
_d__ 4. A molecule that stores energy in animals
_c__ 5. A long chain consisting of many monosaccharides
_f___ 6. A molecule that gives plant cell walls their rigidity.
Match each item related to lipids to the correct statement listed below.
a. / Unsaturated fats / d. / Glycerol + 3 fatty acid chainsb. / Saturated fats / e. / Monounsaturated
c. / Trans fats / f. / polyunsaturated
_e___ 1. lipid molecules containing only one carbon–carbon double bond in their fatty acid chains
_b___ 2. Solids at room temperature, found in animals
_f__ 3. Lipid molecules that contain many carbon-carbon double in their fatty acid chains
_d__ 4. The building blocks of lipids
_a___ 5. Liquids at room temperature, found in plants
_c___ 6. Unsaturated fats that have been chemically modified to become saturated (i.e. margarine)
Match each item related to enzymes to the correct statement below.
a. / substrate / d. / Catalystb. / active site / e. / reactants
c. / enzyme-substrate complex / f. / products
_e___ 1. starting materials of a chemical reaction
_c___ 2. enzyme with its substrate attached to the active site
_a___ 3. the molecule an enzyme acts on in a chemical reaction
_f___ 4. the results of a chemical reaction
_b___ 5. location where the substrate binds to the enzyme
_d___ 6. speeds up a chemical reaction
Match these terms related to cellular respiration with the correct statement below.
a. / Aerobic cellular respiration / d. / lactic acid fermentationb. / pyruvate / e. / Alcohol fermentation
c. / ATP
__a__ 1. uses oxygen to produce ATP
__b__ 2. end product of glycolysis
__e__ 3. glucose is converted to alcohol, carbon dioxide, and ATP
__d_ 4. occurs during strenuous exercise when blood oxygen levels are low
__c_ 5. source of chemical energy in the cell
Tables
Complete the following table describing the indicators used to test for food molecules.
Name of Indicator / Molecule Tested For / Colour Change ObservedBiuret’s Reagent / protein / Blue → purple
Iodine / Starch / Light brown → black
Benedict’s Reagent / Glucose / Blue → dark orange
(after heating)
Sudan (III) / Oil or Lipids / Light red → bright orange
Complete this following chart describing the three types of microscopes.
Type of Microscope / Magnification / Resolution *-size of clear objects / Type of Picture
a) compound light microscope / 400X / 200 nm apart / 2D
Transmission Electron Microscope (TEM) / b) 5,000,000 / 0.2 nm apart
- the distance between atoms!! / c) 2D
Scanning Electron Microscope (SEM) / 300,000X / 10 nm apart / d) 3D
Bonus: How many nanometres in a meter? 1,000,000,000
Diagrams
1. Complete the following table. [8 Marks]
Type of Molecule / Sketch or Diagram / Function in the bodyFat
(triglyceride) / / Warmth
Cushions/protects internal organs
Long term energy storage
Amino acid / / Building block of proteins
Glucose
(monosaccharide) / / Building block of carbohydrates
Unsaturated fat / / Provides long term energy storage in plants
2. Label the parts and indicate the functions of each part in the diagram below.
Number / Name of Part / Function1 / chromatin / Contains genetic material that directs all of the activities of the cell.
2 / nucleus / Surrounds the chromosomes and protects them from the environment inside the cell.
3 / ribosomes / Site of protein synthesis (they help to make proteins)
4 / mitochondria / Site of cellular respiration. This is where glucose is broken down to release energy that the cell can use.
5 / Cell membrane / Controls what enters and exits the cell.
6 / Cytoplasm / Cushions/protects cell organelles. Provides the correct environment for cellular reactions to occur.
7 / Endoplasmic reticulum / Helps to transport materials throughout the cell.
3. Use the following cell membrane diagram to complete the table below.
Name of Structure / Functiona / Carbohydrate chain / helps cells recognize other cells
helps cells attach to other cells
b / Integral protein
(protein channel) / Transports small charged molecules into or out of the cell
c / Cholesterol
molecules / Cholesterol molecules wedge themselves in between the phospholipids. This prevents the phospholipids from getting too close together or from moving too far apart. Therefore, they help to maintain the fluid consistency of the cell membrane.
d / Phospholipid bilayer / The phospholipid bilayer helps to create a semi-permeable membrane that only allows certain molecules to enter and exit the cell.
4. Label the indicated parts of the microscope. [5]
1. body tube
2. rotating nosepiece
3. low power objective lens
4. medium power objective lens
5. high power objective lens
6. stage clips
7. diaphragm
8. light source
9. eyepiece/ocular lens
10. arm
11. stage
12. coarse adjustment knob
13. fine adjustment knob
14. base
5. The cells below are in three different solutions. Review the images and answer the questions below.
Beaker A Beaker B Beaker C
A: _____isotonic___ B: _hypertonic______C: _hypotonic _____
(a) In the space below each beaker, identify each solution as hypotonic, hypertonic
or isotonic.
(b) Explain what has happened to the cells in beaker B?
Water is leaving the cells causing them to shrink.
Short Answer
1. Describe three differences between saturated and unsaturated fats.
Saturated fats – found in animals, solids at room temperature, contain only single bonds between the carbon atoms on the fatty acid chains
Unsaturated fats – found in plants, liquids at room temperature, contain one or more double bonds between the carbon atoms of the fatty acid chains
2. What are essential amino acids? How many amino acids are considered essential?
Essential amino acids are amino acids that the body cannot make and must be obtained through your diet. Eight of the twenty amino acids are essential.
3. How does the presence of an enzyme affect the rate (speed) of a chemical reaction? Explain why.
Enzymes speed up chemical reactions. They do this by helping a reaction proceed without taking part in the reaction. For example, an enzyme may help to break apart a substrate to form products.
4. What are the two types of fermentation? Give the overall equation for each.
Lactic Acid Fermentation
1 glucose → 2 pyruvate +2 ATP→2 lactate
Alcohol Fermentation
1 glucose → 2 pyruvate +2 ATP→2 carbon dioxide + 2 ethanol
5. What are two similarities and two differences between facilitated diffusion and osmosis?
Similarities – both are types of passive transport, both involve the movement of substances from a high concentration to a low concentration
Differences – Facilitated diffusion is the movement of particles across a cell membrane. Osmosis is the movement of water across a cell membrane. Facilitated diffusion requires a membrane protein to move particles across the cell membrane. Osmosis does not require any membrane proteins. Water can simply move through the phospholipid bilayer.
6. How is the rate of diffusion affected by a decrease in the concentration gradient?
A decrease in the concentration gradient causes a decrease in the rate of diffusion (diffusion slows down)
7. Describe one similarity and two differences between facilitated diffusion and active transport.
Similarity – both are methods of movement across the cell membrane, both involve membrane proteins
Differences – Facilitated diffusion is a type of passive transport. Therefore, it does not require energy; however, active transport does require energy. Facilitated diffusion involves the movement of particles from high to low concentration. Active transport is the movement of particles from low to high concentration.
8. a) What is the key difference between aerobic and anaerobic cellular respiration?
Aerobic cellular respiration – requires oxygen to break down glucose
Anaerobic cellular respiration – does not require oxygen to break down glucose
b) Which form is more suited to large organisms such as humans, cows, and fish? Which form is adequate for single-celled organisms such as yeast cells and bacteria? Explain.
Aerobic cellular respiration is more suited for large organisms because it releases more energy from each molecule of glucose (36 ATP). Anaerobic cellular respiration is more suited for smaller organisms because it releases less energy from each molecule of glucose (2 ATP).
9. State three differences between plant and animal cells. (3 Marks)
Plant cells have cell walls and chloroplasts. Animal cells do not have these.
Animal cells have lysosomes and plant cells do not.
Plant cells have one very large vacuoles. Animal cells have many smaller vacuoles.
10. Complete the following three statements that make up cell theory.
a) All living things are ____made up of one or more cells______.
b) Cells are the basic _____structural______and _____functional____ units of life.
c) All cells come from _____pre-existing cells____ .
1