Biology 20 Study Guide

BIOLOGY 20 STUDY GUIDE

2013-2014

Holy Trinity Academy

BIOLOGY 20

Biology 20 consists of 5 units that build on the concepts learned in Science 10. The following outline gives a listing of the units, their major theme, approximate length of time the unit covers in a semester, and the associated chapters in the textbook.

Unit one: Biochemistry, Photosynthesis, and Cell Respiration4 weeks Ch: 5, 6

Unit two: Muscles and Digestive system3 weeks Ch 10, 6

Unit three: Circulatory system and Immunity3 weeks Ch 8

Unit four: Breathing and Excretion3 weeks Ch 7, 9

Unit five: Ecology, Taxonomy, and Evolution5 weeks Ch: 1,2,3,4

Evaluation

Lab reports, quizzes40%

Tests35%

Final Exam25%

Student Expectations

1. Arrive to class on time and prepared

2. Raise your hand to speak. Don’t speak when someone else is speaking

3. Respect each other. Be polite in word and gesture

4. Work diligently in class and complete all homework to the best of your ability

Academic Expectations

Hand in and receive a passing grade on all lab reports and quizzes
Receive a passing grade on all tests
Make up any missed work on the first day you return to school from an absence
Participate actively in all class activities.

Homework Policy

1. Late assignments loose 10% until the work is returned to class. After the assignment is returned to the class the assignment should still be completed and handed in but will lose 50%. It is the responsibility of the student to inquire about missed or alternate assignments.

2. Alternate assignments will be given to those who cannot do some dissections/labs or who missassignments with legitimate reasons.

Supplies: 2” binder, 150 pages lined loose leaf paper, 10 pages graph paper, pen, pencil, 30 cm ruler,

Unit One: Photosynthesis and Cellular Respiration

1. describe the chemical nature of carbohydrates, fats and proteins and their enzymes, i.e.,

carbohydrases, proteases and lipases

Introduction:

The most frequently used elements in living organisms are: O, C, and H. These are used to build, carbohydrates, proteins, lipids, nucleic acids, vitamins, and water.

Other elements used in smaller amounts include N (amino acids), Ca (bones), P (energy storage), Fe (RBC) Na (nerve impulse and water regulation)

Water:

Property / Description / Significance to life
Transparency / Clear liquid / Allows light to transmit through so photosynthesis can take place in water environments
Cohesion / Molecules are ‘sticky’ / Allows water transport in plants and organisms to live on the surface of rivers, ponds, lakes
Solvent / Many substances dissolve in it / Allows the transport of nutrients, gases and wastes in organisms and inside cells
Thermal / Has high heat capacity / Protects earth and ecosystems from temp extremes, cools organisms

Minerals: are inorganic compounds or pure elements such as, phosphorus, calcium, iodine, potassium, sodium

Vitamins: are organic compounds that function as coenzymes in metabolic pathways

The process of digestion involves the breaking of chemical bonds that hold the carbohydrate, proteins and fats together. This is called hydrolysis. This involves the addition of a water molecule into the carbohydrate, protein or fat splitting the compound into two smaller compounds. The opposite process, the building of a larger molecule from two smaller molecules by removing an H atom and an OH group from carbohydrates, proteins, or fats, allowing them to join together, is called dehydration synthesis, or condensation. Both processes require enzymes to make the reaction go faster.

Carbohydrates

Purpose: Store energy, structural components of cells and cell membranes

Structure: made of elements, C,H, and O

Examples: monosaccharides C6H12O6, glucose, fructose, galactose

Disaccharides C12H22O11, sucrose, maltose, lactose

Polysaccharides, glycogen, starch, wax

Of the disaccharides: Sucrose is made from glucose and fructose

Lactose is made from glucose and galactose

Maltose is made from glucose and glucose

Lipids: Fats and Oils

Purpose: store energy, protect internal organs, make hormones, structural components of cells

Fats: produced by animals and are solid

Oils: produced by plants and animals and are liquid

Structure: triglyceride fats are made from 1 glycerol molecule and three fatty acids

Polyunsaturated fatty acids: have many double bonds between carbons, creates softer substance

Monounsaturated fatty acids: have only one double bond,

Saturated fatty acids: have no double bonds, usually solid at room temperature, harder

Cholesterol: made from fat, used to make cell membranes, and important hormones

Proteins

Proteins are made from the elements C, O, H, and N. These elements link together to make an amino acid.

There are 20 different amino acids used to make all proteins for living things on earth.

Six functions of proteins:

1)enzymes—are globular proteins, speed up reactions, ex. Amylase

2)hormones—some are also made from steroids (lipids), ex. Insulin

3)antibodies—are globular proteins that help in defense against foreign substances

4)structural proteins—are fibrous proteins, ex. Tendons, cartilage, collagen, keratin

5)transport—form part of the cell membrane and regulate what enters/leaves the cell

6)carrier—pick up various substances, attach to substances, ex. Hemoglobin

Denature- when proteins are temporarily changed by physical or chemical processes. Enzymes are denatured by mild temperature or pH. The change is reversible.

Coagulation- when proteins are permanently changed by chemical or physical processes. If enzymes are heated too much they with ‘melt’ or break apart; frying and egg-the egg white coagulates with heat.

2. explain enzyme action and factors influencing their action

Enzymes

Are all made of proteins
Are over 1000 different enzymes in the human body
Most names of enzymes end in ase
Function as catalysts. A catalyst speeds up chemical reactions but are not altered by the reaction and can be used over and over again.
They only accelerate the rates of chemical reactions that already occur, they cannot make a reaction occur that does not occur spontaneously.

The Lock and Key Model

The enzyme is the key and the substrate is the lock
In order to catalyze a reaction, an enzyme must come in contact with the reactant molecules
This compound is called the enzyme-substrate complex
The substrate attaches to the enzyme at the active site of the enzyme
Either the substrate is broken up (catabolism) or the substrate is attached to another substrate (anabolism)
Most enzymes have high substrate specificity, they will attach to only one type of compound (this depends on the shape of the active site)

How do enzymes work?

The presence of an enzyme will speed up the reaction because the active site will facilitate the chemical change. This happens by means of lowering the activation energy. Every reaction requires a certain amount of activation energy. This is the energy required to break a bond (catabolism) or to make a bond (anabolism).

Competitive inhibitors- a molecule that is similar in shape to the substrate molecule and binds to the active site preventing the substrate from attaching (there is competition for the active site. Ex. Inhibition of folic acid synthesis in bacteria by the sulfonamide drugs (antibiotics)

Noncompetitive inhibitors- a molecule binds to an enzyme, but not on its active site, causing a structural change in the enzyme which alters the shape of the active site. Ex. Heavy metals (mercury, silver) and cyanide inhibition of any enzymes in the electron transport chain

Factors that affect enzyme activity

Temperature: increasing temp increases enzyme activity. Above the enzymes optimum temperature excess heat will denature enzymes altering the active site rendering the enzyme inactive. Continued heating will destroy the enzyme (heat affects any protein) (results in denaturation or coagulation)

Concentration: increasing concentration of the enzyme increases the rate of the reaction, but only small amounts of enzyme are required because they can be reused and they work fast.

pH: when an enzyme is outside its pH range it is denatured decreasing its activity.

Inhibitors: they prevent the attachment of the substrate, hence slow down or stop the reaction.

Cofactors: are substances that attach on to the enzyme (other than the active site) to complete the enzyme molecule and allow the enzyme to attach to the substrate Ex. Minerals in our diet. If there are no cofactors the enzyme cannot work.

Coenzymes: are substances (vitamins) that attach on the the enzyme at the active site and allow the enzyme to attach to the substrate. If there are no coenzymes present then the enzyme cannot work.

Tests for Carbohydrates, Proteins, and Fats

Test name / Nutrient tested for / Test description
Benedicts test / monosaccharide / Blue to yellow, green, red, brown
Iodine test / Starch / Orange/yellow to blue/black
Biurets test / Protein / Blue to pink/purple
Sudan IV test / Lipid, oil, fat / Pink to red
Translucence test / Lipid, oil, fat / Brown to semi-clear

General Outcome 1: Students will relate photosynthesis to storage of energy in organic compounds.

1. explain, in general terms, how pigments absorb light and transfer that energy as reducing

power in nicotinamide adenine dinucleotide phosphate (NADP), reduced nicotinamide

adeninedinucleotide phosphate (NADPH) and finally into chemical potential in adenosine

triphosphate (ATP) by chemiosmosis, describing where those processes occur in the

chloroplast

2. explain, in general terms, how the products of the light-dependent reactions, NADPH and

ATP, are used to reduce carbon in the light-independent reactions for the production of

glucose, describing where the process occurs in the chloroplast.

Photosynthesis

This process occurs in two stages:

Light dependent reaction, Photolysis, light reaction

This occurs in the thylakoid membranes inside the chloroplasts
Light is absorbed by chlorophyll ‘a’ molecules (pigments) found in clusters called photosystems
This light causes electrons in chlorophyll to be released
The released electrons are “absorbed” by chlorophyll ‘b’ molecules. The electrons are transported from “a” to “b” through special protein carriers in the thylakoid membrane. As the electrons are transported they lose energy. This energy is used to actively transport (by other proteins in the membrane) hydrogen protons to the inside of thethylakoid disc. This builds up a higher concentration of hydrogen protons inside the thylakoid. The protons will then diffuse out through another special membrane protein that will join ADP to P to make ATP. This process is called Chemiosmosis.
The original chlorophyll a molecules are unstable and remove electrons from water molecules, splitting water into H protons and oxygen. This is called photolysis.
The oxygen diffuses out of the cell and is released through the stomata
The H protons are added to NADP to form NADPH using electrons released by chlorophyll b.
NADP (nicotinamide adenine dinucleotide phosphate) is a transport truck that carries hydrogen (released from water molecules) from one reaction to another in photosynthesis, from the light dependent reaction to the light independent reaction.

Light independent reaction, Calvin Benson cycle

This occurs in the stroma
Also called carbon fixation because carbon dioxide molecules are fixed into carbohydrates.
NADPH move into the stroma and release their H protons
This Hydrogen combines with other chemicals and carbon dioxide to make carbohydrates.
The energy needed to create this comes from ATP breaking down into ADP and P

Effects of temperature, light intensity and carbon dioxide concentration on the rate of photosynthesis

Temperature: As temperature increase the rate of photosynthesis increases, reaches a maximum, then decline sharply as the enzymes are denatured by the increased heat.

Light intensity: as light intensity increase the rate of photosynthesis increases then reaches a maximum and levels off

Carbon dioxide: as Carbon dioxide levels increase the rate of photosynthesis increases, reaches a maximum, then levels off. Only a low conc. is needed (less than 5 %) higher concentrations cause the pH of the cell to drop which inturn could cause the enzymes to denature.

General Outcome 2: Students will explain the role of cellular respiration in releasing energy from organic compounds.

1. explain, in general terms, how carbohydrates are oxidized by glycolysis and Krebs cycle to

produce reducing power in NADH and FADH, and chemical potential in ATP, describing

where in the cell those processes occur

2. explain, in general terms, how chemiosmosis converts the reducing power of NADH and

FADH to the chemical potential of ATP, describing where in the mitochondria the process

occurs

3. distinguish, in general terms, between animal and plant fermentation and aerobic

respiration

4. summarize and explain the role of ATP in cell metabolism

5. identifying factors affecting the rate of cellular respiration

Carbohydrate Metabolism, Glucose Metabolism, Cellular Respiration

Where does glucose come from and how does it get into the cells?

Polysaccharides and disaccharides are broken down to monosaccharides (glucose, fructose, and galactose.
These nutrients are absorbed into the blood and brought to the liver
The liver converts fructose and galactose into glucose. It also regulates blood glucose levels.
The cells absorb glucose from the blood (capillaries)

The processes that go on inside the cell (actual cell respiration)

Cellular respiration is the process where food energy, or more specifically the chemical bonds inside glucose, is converted into chemical bonds that make A.T.P. The overall reaction is as follows:

1 glucose + 6 oxygen  6 carbon dioxide + 6 water + 36 A. T. P. + waste heat

ATP—is adenosine triphosphate. This molecule store significant amounts of energy in the bond that holds the last phosphate.

The processes (reactions) that occur to break down glucose involve oxidation and reduction reactions.

Oxidation—the removal of hydrogen atoms from a molecule. The hydrogen are picked up by molecules called coenzymes.

Reduction---the addition of hydrogen atoms to another molecule. The coenzymes add the hydrogen atoms to other molecules.

N.A.D.—nicotinamide adenine dinucleotide—a coenzyme that picks up hydrogen atoms (analagous to an empty dump truck). When it picks up hydrogen it becomes N.A.D.H ( the full dump truck)

F.A.D.---Flavin adenine dinucleotide—another conezyme that picks up hydrogen atoms. It becomes FADH

Reduction always follows oxidation, with the use of enzymes and coenzymes

The Fate of Glucose

If not needed:

glucose is converted to glycogen, stored in the liver and muscle cells
if glycogen storage space is filled glucose is stored as fat
if glucose cannot be stored or concentrations of glucose are too high it is excreted by the kidney

If needed:

glucose is absorbed by the cells, is oxidized, and the energy released is stored in A.T.P. or given off as body heat

Glucose oxidation – occurs in 3 stages:

1 glycolysis—does not need oxygen

citric acid cycle, or Krebs cycle
electron transport chain

(stages 2 and 3 will only occur in the presence of oxygen.

Glycolysis

occurs in the cytoplasm
does not use oxygen
splits one glucose (6carbon) into 2 pyruvic acid (3carbon)
produces 2 pyruvic acid, 2 NADH , 4ATP
uses 2 ATP to phosphorylate glucose. This prevents glucose from diffusing out of the cell as well as makes glucose more reactive

Fate of Pyruvic Acid

1. if no oxygen—pyruvic acid will be converted to lactic acid. This step uses NADH . This is called anaerobic respiration in animal cells. The lactic acid lowers pH and prevents muscle contractions. This process also occurs in some yeast cells producing alcohol instead of lactic acid as an end product, called alcoholic fermentation.

2. If oxygen is present pyruvic acid enters Krebs cycle. This occurs inside the mitochondria

Anaerobic Respiration (glucose  lactic acid or alcohol) (fermentation)

occurs in muscle cells during strenuous exercise, when the cell uses oxygen faster than the circulatory system can provide it.
Not all cells in the body do this, i.e. brain cells die without oxygen
Lactic acid decreases pH, muscles cannot contract when pH gets to low
Muscle fatigue is overcome when the oxygen debt has been met by increased breathing and heart rate increasing the supply of oxygen to the muscle cells
Lactic acid is removed from cells and converted to glycogen in the liver
Net ATP produced is 2.

Aerobic Respiration

uses oxygen
occurs in any cell that has mitochondria
occurs in 3 stages:

glycolysis
krebs cycle
electron transport chain

(both b and c occur inside the mitochondria)

Mitochondria anatomy

Cristae: folded membranes inside the mitochondria, where the electron transport chain is found

Matrix: fluid inside the mitochondria surrounding the cristae, where krebs cycle occurs

Glycolysis

once pyruvic acid is formed it enters the mitochondria
when inside the mitochondria the pyruvic acid (3carbon) is converted into a new 2carbon compound called acetyl coenzyme A. For this to occur carbon dioxide is removed (decarboxylation) as well as hydrogen from NADH. This is called the “link reaction”.

Krebs cycle

is a cyclical process where acetyl coenzyme A is added to a 4 carbon compound to make a 6 carbon compound. This 6 carbon compound is then broken down into the original 4 carbon compound. In the process 2 carbon dioxide molecules are removed as well as NADH and FADH
for every one glucose molecule this cycle occurs twice.
This occurs in the matrix

Electron Transport Chain

is a series of oxidation reduction reactions that occur on the cristae
hydrogen electronsare transferred from one electron acceptor (cytochrome) on the cristaeto another releasing energy. The energy released is used to actively transport hydrogen protons to the space between the cristae and the outer mitochondrial membrane (called the intermembrane space)
as hydrogendifuse back across the cristaeATP is produced (chemiosmosis)
The last electron acceptor is the strongest, oxygen, forming water
If the cell lacks oxygen the E.T.C. does not function which prevents Krebs cycle from working.
NADH drops its hydrogen at the first cytochrome, producing 3 ATP
FADH drops its hydrogen at the second cytochrome, producing 2ATP
NAD and FAD can go back to Krebs cycle to pick up more hydrogen

Other metabolic pathways/other sources of fuel for cell respiration