Biochemistry Unit Review

Part 1

Biomolecules

“Organic” molecules have carbon.“Inorganic” molecules do not have carbon. Monomers are small parts that make up a

large polymers.

Monomer + Monomer + Monomer = Polymer

BiomoleculesOrganic Molecule

Elements Function Monomer Test

Carbo-hydrate

C, H, O Fast energyMonosaccharides (like glucose)

Benedict’s – glucoseIodine - starch

Lipid C, H, O

Store long-term energy, make up cell membranes

Fatty acids and glycerol

Paper bag

Protein C, H, O, N

Growth and repair, speed up chemical reactions

Amino acids Biuret’s

Nucleic Acid

C, H, O, N, P

DNA: carries hereditary infoRNA: makes proteins

Nucleotides Is it living?

Water & pHWater is a universal solvent – it dissolves most

molecules and ions. pH is a measure of the amount of Hydrogen ions in

a solution.pH scale goes from 0 – 14.

 1-6 = Acid – the lower the pH, the stronger the acid.

Ex. 2 is a stronger acid than 5

7 = NEUTRAL – based on pure water 8-14 = Base (alkaline) – the higher the pH, the

stronger the base.Ex. 14 is a stronger base than 11

EnzymesEnzymes are a special type of protein that speeds up a

chemical reaction by lowering the activation energy of a reaction.

 Enzymes are biological catalysts The material an enzyme works on is called the

substrate. The pocket or groove where the substrate fits into on

the enzyme is called the active site. Enzymes are named for the substrate that they work

with. Names usually end in –ase. Enzymes can be “denatured” by a change in

temperature or a change in pH.

Practice Questions

1. A molecule that is found on the surface of most cells is responsible for communication between the cells. This molecule is made up of long chains of amino acids and is specific to each cell type. This molecule is a

 A.lipidB.carbohydrateC.DNA strandD.Protein

2. Which statement best describes the function of a lipid in a cell?

 A.storing and transmitting heredityB.forming part of biological membranesC.forming amino acid chainsD.storing phosphorus

3. Which of the following factors is most likely to affect the function of an enzyme?

 A.catalystsB.size of beakerC.proteinsD.temperature

4. Which of the following statements best describes a function of an enzyme?

 A.All enzymes work on all substrates.B.Enzymes are specialized proteins that serve

as catalysts.C.Enzymes are carbohydrate-based molecules in

all cells.D.The structure of enzymes is changed during a

chemical reaction.

5. Which of the following substances would show a positive brown paper test for lipids?

 A.applesB.baconC.crackersD.water

6. Which pH indicates a substance that is more basic than a substance with a pH of 9?

 A.6B.2C.8D.12

7. Which of the following is a list of elements that make up the structure of a carbohydrate?

 A.carbon, nitrogen, oxygenB.hydrogen, carbon, oxygenC.nitrogen, sulfur, oxygenD.oxygen, carbon, phosphorus

8. Which of the following is a function of proteins?

 A.storing energyB.storing wasteC.growth and repairD.breaking chemical bonds

9. Which of the following organic molecule tests is correctly paired with its organic molecule?

 A.proteins – brown paperB.glucose – biuretC.starch - iodineD.lipid – benedicts

10. Which biomolecules store and transmit genetic information?

 A.carbohydratesB.lipidsC.nucleic acidsD.proteins

11. Which of the following best describes the function of carbohydrates?

 A.They code for proteins.B.They form biological membranes.C.They provide a source of energy for an

organism.D.They control reaction rates in a cell.

Biochemistry Unit Review

Part 2

The Cell TheoryThe cell theory was developed with the help of

the light microscope.

The cell theory states that:1. all organisms are composed of cells2. cells are the basic unit of structure and function in living things3. cells come from pre-existing cells

The Cell TheoryCell Theory People:

a. Anton von Leeuwenhoek microorganismsb. Robert Hooke named cellsc. Matthias Schleiden all plants made of cellsd. Theodore Schwann all animals made of cellse. Rudolph Virchow new cells come from existing cells.

MicroscopesTotal Magnification =

eyepiece (ocular lens) x objective lens

Eyepiece = 10xObjectives = 10x, 40x, 65x

Greatest possible magnification =

Ex. Total magnification 600x = Eyepiece 10x X Objective 60x

Under the microscope, letters get put upside down and backwards.Ex. “e” appears as “___”.

Types of microscopes:1. light microscope2. scanning electron

microscope 3. transmission electron

microscope

Prokaryotes vs. Eukaryotes Make a Venn

diagram using

NucleusOrganellesDNACell membrane

the following words:

CapsuleReproducePlantsBacteriaAnimals

Eukaryotic OrganellesNucleus – controls the cell (where DNA is found)Ribosomes – site of protein synthesis (make proteins)Plasma (Cell) Membrane – controls what comes in

and outEndoplasmic reticulum– series of channels that act

as a transport systemGolgi Apparatus – packs, sorts, and ships moleculesMitochondria – powerhouse; makes energy; site of

cellular respirationChloroplast – site of photosynthesisVacuole – stores water, food and wasteCell wall – used for structure and support in plant

cells

Eukaryotic OrganellesPlant cells are different from animal cells in

three ways:1. plant cells have a cell wall, animal cells don’t2. plant cells have chloroplasts, animal cells don’t3. plant cells have larger vacuole

Practice Questions

1. If an organism does not have membrane-bound organelles, what is it called?

 A.simpleB.eukaryoticC.prokaryoticD.complex

2. Which organelle pictured is responsible for transforming energy?

 a. b.

c. d.

3. During the period from 1838-1855, German scientists Matthias Schleiden, Theodor Schwann, and Rudolph Virchow contributed greatly to the understanding of plant and animal cells. Their cell theory includes all of the following ideas except which one?

 A.All living things are made of cells.B.Cells are the basic units of structure and

function of living things.C.Cells come from pre-existing cells.D.Viruses are not made of cells.

4. Prokaryotic and eukaryotic cells are distinguished from each other by which of the following?

 A.Prokaryotic cells include most cells, other than

bacteria, and lack a nucleus and membrane-bound organelles.

B.Prokaryotic cells include mainly bacteria, and lack a nucleus as well as membrane-bound organelles.

C.Prokaryotic cells include most cells, other than bacteria, and contain a nucleus and membrane-bound organelles.

D.Prokaryotic cells include mainly bacteria, and contain a nucleus as well as membrane-bound organelles.

5. Which of the cell organelles labeled below helps you determine if this is an animal cell or a plant cell?

 A.nucleusB.cell wallC.ribosomesD.mitochondria

6. What is the function of the Golgi apparatus? A.manufacture proteinsB.package and transport proteinsC.store proteinsD. break down proteins to release energy

7. A student identifies an unknown cell as being eukaryotic. Which of the following did she most likely identify in order to draw this conclusion?

 A.nucleusB.cell wallC.chloroplastsD.cell membrane

8. Which of the following best describes the function of a ribosome?

 A.making proteinsB.digesting lipids, carbohydrates and proteinsC.storing water, proteins, salts and

carbohydratesD.providing structural support for the cell

Biochemistry Unit Exam Review

Part 3

Cell Membrane

The cell membrane (plasma membrane) is made up of two layers of lipids, so it is called a lipid bilayer.

 Proteins can also be found inside the

membrane. They can act as receptors, channels and pumps.

 

Cell Membrane

The lipid bilayer contains phospholipid molecules with non-polar tails and polar heads.

They hydrophobic tails are “water hating”, while the hydrophilic heads are “water loving”.

They are arranged in the membrane with the tails together and the heads on the outside.

Cell Membrane

Most biological membranes are “selectively permeable”, or some substances can pass across the membrane while others cannot.

Cell TransportThe selective permeability of the cell membrane is

most closely associated with the maintenance of homeostasis.

 Two main types of transport are passive and active. Passive Transport – does not require energy; moves

molecules from high concentration low concentration.Diffusion – molecules move from high lowOsmosis – water moves from high low

(water moves from less salt to more salt)Facilitated Diffusion– large molecules move from high low through a transport protein

Cell TransportActive Transport – requires energy (ATP); moves

substances from low concentration high concentration.

 Equilibrium – the concentration of dissolved

substance is the equal throughout a system. 

Cell TransportWhat happens to a cell when …a.it is placed in a solution with a higher salt

concentration – it will shrink

b.it is placed in a solution with the same salt concentration stay the same

c. it is placed in a solution with lower salt concentration – it will swell

PhotosynthesisPhotosynthesis is the conversion of light into

chemical energy.Equation: CO2 + H2O + Light C6H12O6 + O2

Carbon dioxide + Water + light energy Glucose (sugars) + oxygen

 Photosynthesis occurs in the chloroplast and the

sunlight required for the reaction is absorbed by the chloroplast pigment chlorophyll.

 There are 2 stages to photosynthesis:

1. Light-dependent (Electron Transport Chain)2. Calvin Cycle (Light-independent)

Aerobic Cellular RespirationCellular respiration is the process that releases

energy by breaking down glucose and other food molecules in the presence of oxygen.

 Equation: C6H12O6 + O2 CO2 + H20 + ATP (energy) Glucose + oxygen Carbon Dioxide + water + ATP

 Cellular respiration occurs in the mitochondria.The most ATP is made during aerobic cellular

respiration (36 / molecule of glucose) There are 3 stages to aerobic cellular respiration:GlycolysisKreb’s CycleElectron Transport Chain

Anaerobic Cellular RespirationAnaerobic respiration occurs when there is a

lack of oxygen for the cells. Anaerobic respiration has 2 stages:GlycolysisFermentation There are 2 types of fermentation:Lactic Acid

Forms lactic acid as a waste product.Lactic acid creates sore muscles after exercising.

AlcoholicForms ethanol as a waste product.Used in making bread, beer & wine.

Practice Questions #3 and #4

1. A cell moves particles from a region of lesser concentration to a region of greater concentration by

 A.active transportB.facilitated diffusionC.osmosisD.passive transport

2. Which conditions shown below may cause a cell to burst?

3. What cell process is responsible for the transport shown below?

A.active transportB.osmosisC.facilitated diffusionD.passive transport

4. Which process does an organism use to move large molecules into a cell?

 A.simple diffusionB.exocytosisC.endocytosisD.facilitated diffusion

5. Blood plasma and sea water have nearly the same salt concentration. What will happen to a red blood cell placed in pure water?

 A.it will swellB.it will disintegrateC.it will shrinkD.it will divide

6. Cells have a selectively permeable membrane. What is the primary purpose of this membrane?

 A.to keep all of the cytoplasm inside the cellB.to control which materials enter and leave the

cellC.to allow photosynthesis to occurD.to manufacture proteins

7. Which of the following statements about osmosis and diffusion is correct?

 A.Osmosis requires energy and diffusion does not.B.Both osmosis and diffusion involve the movement

of molecules from areas of higher concentration to areas of lower concentration.

C.Diffusion is the movement of water from areas of higher concentration to areas of lower concentration.

D.Osmosis is the movement of water from areas of lower concentration to areas of higher concentration.

8. Which form of transport is represented in the illustration below?

 A.facilitated transportB.diffusionC.active transportD.osmosis

9. An animal cell is placed in a solution of distilled water. If left overnight, this cell will

 A.swell and burstB.shrivel and dieC.undergo chemosynthesisD.remain the same, since it has a cell wall to

protect it

1. Energy is released from ATP when the bond is broken between

 A.two phosphate groupsB.ribose and a phosphate groupC.adenine and a phosphate groupD.adenine and ribose

2. How are the processes of photosynthesis and respiration linked?

 A.One takes place during the day, the other at

night.B.One takes place in animals, the other in

plants.C.The reactants of one are generally the

products of the other.D.They are identical, but in the reverse order of

each other.

3. Which of the following produces the greatest amount of ATP?

 A.gylcolysisB.Krebs cycleC.Electron transport chainD.fermentation

4. Which of the following statements about photosynthesis is correct?

 A.The products of photosynthesis are sugar and

oxygen.B.Photosynthesis occurs in mitochondria.C.Sunlight is not necessary for photosynthesis

to occur.D.The products of photosynthesis are sugar and

water.

5. Which of the following is the correct sequence of events in the process of photosynthesis?

 A.Calvin cycle, electron transport chain,

absorption of light energy.B.absorption of light energy, Calvin cycle,

electron transport chainC.electron transport chain, absorption of light

energy, Calvin cycleD.absorption of light energy, electron transport

chain, Calvin cycle

6. A cell that is capable of carrying out both photosynthesis and respiration is probably a

 A.prokaryotic cellB.mitotic cellC.plant cellD.animal cell

7. The equation below summarizes what biological processes?

 Light + 6H20 + 6CO2 C6H12O6 + 6O2 + ATP

 A.chemophotosynthesisB.fermentationC.photosynthesisD.cellular respiration

8. During strenuous exercise, animals cannot take in enough oxygen to supply their cells with the necessary oxygen. As a result, they carry out lactic acid fermentation to supply their cells with the necessary energy. Lactic acid fermentation is a type of

 A.anaerobic respirationB.aerobic respirationC.alcoholic respirationD.ATP respiration