biology notes 1.1-1.2- non ib

8/14/2019 Biology Notes 1.1-1.2- Non IB

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October 2007 Biology Notes 1.1 1.2

Organic Compounds Refers to molecules that contain both carbon and hydrogen (O 2 ,

H2O, and CO 2 are all inorganic) All organic compounds in living cells have a carbon backbone; carbon

can form up to four bonds with different atoms. Hydrocarbon molecules contain only carbon and hydrogen and come in

a variety of sizes and shapes, chains and rings.

Macromolecules Large organic molecules There are four classes of macromolecules found in living organisms:

carbohydrates, lipids, proteins, nucleic acid.

Structure and Function of MacromoleculesOrganic molecules that weigh more than 100 000 g/mol are referred to asmacromolecules.

These macromolecules are constructed of smaller units called polymers

long chain of repeating units. These polymers are subdivided into their basicunits called monomer .

Making and breaking of polymers:Dehydration synthesis: is an anabolic building up process by which twomolecules are chemically bonded through the use of enzymes and a loss of water.

Example: glucose + glucose = maltose + waterHydrolysis: is a catabolic process by which the bonds between monomersare broken by the enzyme and the addition of water.

Example: sucrose + water = glucose + fructose

The Four Major Organic Compounds found in Living ThingsA. Carbohydrates: include sugars and their polymers.

1. Monosaccharides: The basic formula (CH 2O) end in -oseExamples: glucose, fructose, and galactose are hexose (6carbon) sugars. Deoxyribose and ribose are (5 carbon) pentosesugars.

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GlucoseC6H12 O 6


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2. Disaccharides: These are double sugars with the formulaC12 H 22 O 11 . Notice that one molecules of water is missing from theformula. The covalent bond holding the two monomers together iscalled a glycoside linkage.

Examples: sucrose = glucose + fructose; maltose = glucose +glucose; and lactose = glucose + galactose

3. Polysaccharides: The basic formula is (C 6H10 O 5)n .A. Storage Polysaccharides: starch is a plant storagepolysaccharide that is composed entirely of glucose. Amylose isthesimplest form of starch. Amylopectin is more complex andis branched. Glycogen is an animal starch stored in the liverand muscles of vertebrates.

B. Lipids: A group of polymers that have one characteristic incommon, they do not mix with water. They are hydrophobic.Some important groups are fats, phospholipids, and steroids.

Fats: are large molecules composed of 2 types of monomers, glycerol (an alcohol containing 3 carbons) and3 fatty acids molecules. The two types of fatty acids aresaturated and unsaturated.

The saturated fatty acids do not contain any doublebonds between the carbons. Unsaturated fatty acidscontain one or more double bonds between their carbons.

These double bonds cut down on the number of hydrogenatoms that can be attached to the carbon in the molecule.

This causes the molecule to bend or kink at each of thedouble bond sites.

Function of fats: Acts as insulation in higher vertebrates Serves as an energy storage source 1g=9Kcal of

energy And acts as a shock absorber for internal organs

Phospholipids: structurally related to fats but contain 2fatty acids and one molecule of phosphate. Thesemolecules are found making up the plasma membrane of cells. They exhibit a polar and non polar quality. The

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phosphate group is hydrophilic while the fatty acid area ishydrophobic.

Steroids hormones: Lipids characterized by a carbonskeleton of 4 fused rings. Cholestral is an importantsteroid found in all animal tissue. Plants do not containcholesterol. Cholesterol functions in many ways; it is aprecursor from which many of the bodies steroids areconstructed from. It also adds strength to the plasmamembrane in animal cells.

C. Proteins polypeptide: macromolecules that make up 50%of the dry weight of most cells. Their monomers are calledamino acids. Most amino acids consist of a carbon bonded to anamino group, hydrogen, an R group, and a carboxyl group whichmakes it an acid. There are 20 different amino acids. The bondformed between amino acids is called a peptide bond.

Types of proteins:1) Structural: functions in support; examples: elastin,

collagen, and keratin2) Storage: food sources, examples: ovalbumin and casein3) Transport: moves other substances, examples:

haemoglobin and cell membrane proteins4) Hormonal: coordinates bodily activities, example insulin5) Contractile: movement, examples: actin and myosin6) Antibodies: defense, examples: Ig.E, IgA, and Ig.G7) Enzymes: aid in chemical reactions, examples: amylase

and proteases

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* Haemoglobin 4 polypeptidesFolding back of polypeptide on itself increase stability

D. Nucleic Acids: DNA and RNANucleotides are the monomers that come together to form a nucleicacid. They contain either a ribose or deoxyribose, sugar, phosphate,and a nitrogenous base (guanine, adenine, cytosine, thymine, oruracil). Base pairing rule. A T, A U, C - G

DNA RNA both

DNA has a double helix shape, while RNA is single stranded.

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Cell Parts and Functions

Cell part Function Location & Structure

Cell(plasma)

membrane

- Selectively permeable, meaning it

regulates the flow of materials such asnutrients and water in and out of thecell.- It connects the cell to the outsideenvironment.

It surrounds the cell andholds it together. It isthe outermost part of acell.Single membrane.

Cell wall

- It protects the plant cell, as well asimproving its durability.- It also helps maintain the shape of thecell itself, when there is too much or toolittle water.

Found only in a plantcell, and is theoutermost part of aplant cell.

Nucleus

- Control center of a cell.- Co-ordinates, controls, and manages a

cells functions.- A storage center of all information in acell.- Contains chromosomes and DNAblueprints for making proteins.

Surrounded by a doublelayered membrane,central area of cell.

Nuclearmembrane

- Holds the cells DNAS.- Selectively permeable.

Surrounds the Nucleusand is double layered.

Chromatin

Chromosomes

- It is strand of DNA found within thenucleus.- One of the two duplicatedchromosomes during mitosis andmeiosis is called a Chromatid.- Condensed chromatin are calledChromosomes.

Found inside thenucleus of a cell.

Nucleolus - Manufactures ribosomes. The darker inner portionof the nucleus.

Cytoplasm- Mostly water, gel-like material- Creates the chemical environment inwhich the other cell structures work.

Surrounding the cellinside the cellmembrane.

Nucleoplasm

- Highly viscous liquid.- Nucleotides and enzymes aredissolved in the nucleoplasm.

Surrounds thechromosomes andnucleoli.Enveloped by thenuclear membrane ornuclear envelope.

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Endoplasmic reticulum

- A series of canals which carrymaterials through the cytoplasm.- They transport various nutrients,waste, and other materials to variousparts of the cell.

Rough ER- Processes and modify proteins withthe help of enzymes embedded on theinner surface of the rough ER.

Smooth ER- Processes macromolecules such aslipids and synthesizes phospholipids.- Specialize functions in different cells

A series of canals whichlook smooth without

ribosomes and roughwith ribosomes.

Golgiapparatus

or complex

- They package nutrients and food forfurther use elsewhere in a cell (cellmembrane and within the cell aslysosomes).- Receives vesicles from the ER, containenzymes for modifying proteins andlipids.

A stack of flattenedmembrane-bound sacs.

Vacuoles - They store many things in a cell, suchas nutrients, water and waste.

Large balloon likecontainers, very large inplant cells.

Lysosomes

- Membrane-bound vesicle.- Digest food, and process waste(through endocytosis).- Like small suicide sacs which destroyold and worn out parts of a cell.

Small sacs found in acell, circular and small.

Mitochondria

- It transforms the energy stored indifferent macromolecules into a formthat can be used throughout the cell

(called ATP)

Double layeredmembrane(mitochondrion).

Plastids chloroplast

s,chromoplas

ts,leucoplasts

- a plastid (organelle used to synthesizeor store food) contains chloroplast.- transfers the energy in sunlight intostored energy in carbohydrates (duringphotosynthesis)- Contain chlorophyll which containsgreen pigment and some carotenoidswhich hold yellow or orange pigment.- Chlorophyll traps radiant sun energythen manufactures complex organicmolecules from simple raw organic

materials.- Where starch, oil and protein arestored.

Contains stackedinternal membranesacs.

Microtubules

- Rod-like tubes- Acts like tracks along whichorganelles, such as vesicles andmitochondria can move and stabilizethe shape of cells with irregularcontours.

Forms the mainstructural component of spindle fibres andcentrioles, cilia, andflagella

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Microfilaments

- Form a dense web under cellmembrane allowing for the movementof the membrane- Protein that can contract and thatforms a key component of muscle cells.

Actin filaments.Long, think flexiblecables.

Cytoskeleton

- Network of three interconnected fibresthat maintain cell shape and allow formovement of cell parts.

Allow movement foractin filaments,intermediate filaments,and microtubes.

Flagellaand cilia

- Move cell through its environment.- Cilia propels food toward a specialfeeding groove.

Short cylindricalprojections.Wave-like motion /Undulating, whip-likemotion

Centrioles - They are where spindle fibers attachduring mitosis and meiosis.

Mostly only in animalcells, barrel shaped andsmall. .

Vesicles - Transport sac.Small membrane-bound.

Ribosomes- Are required for the manufacturing of protein which is energy for the cell.- They are the site of protein synthesis.

Can sit freely within thecytoplasm or beattached to theEndoplasmic Reticulum.

Tiny, two-part structure.

Functions of fluid mosaic mode l:1) Controls movement in and out of cell2) Protects cell contents from eternal environment.3) Allows compartmentalization of cell parts4) Communicates between outside and inside of cell.

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Integral proteins:Provides stability for the cell membraneOften have receptors attached oligosaccharides, glycoprotein,glycolipid - act as signal receptors for enzymes, hormones otherchemicals, so that all can turn internal functions on and off.

Transport protein: Membrane channel. Helps substance move fromone side of cell to other

Cholesterol: embedded in cell membrane to provide stability to cell.

Cellulose: polysaccharide composed of glucose subunits that form the maincompounds of the cell wall.

Amylose: simplest form of starch. Amylopectin is more complex andbranched.

DNA: double helix, contains information on making RNARNA: single long chain, contains info for making proteins.

Cholesterol is a steroid which adds strength to the plasma membrane inmany ways, many of the bodies steroids are constructed from cholesterol.

Saturated Fat Unsaturated Fat1. Solid at room temperature. 1. Liquid at room temperature.2. Found mostly in animals. 2. Found mostly in plants.

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3. No double bonds between carbons. 3. Double bonds found between carbons.

Why do bananas turn sweeter as they age? The carbohydrates in green bananas are primarily starches that turn to sugaras the fruits ripen.

Investigation 1A: Testing Macromolecules:Iodine solution for starch : yellow blackBenedicts solution + heat for glucose : blue orangeSudan IV solution for lipids : red blackBiuret reagent for protein : blue purple

Pre-lab Questions: Amino acid contains a nitrogen atom, which is not present in a sugar

molecule.

Two health hazards related to using a copper sulphate solution includesthe inhalation of dust which may cause irritation to the upperrespiration tract, the swallowing of toxic orally and it is also corrosiveto eyes upon contact.

Eukaryote: organisms with cells containing nuclei. Contain organellescompared to prokaryote. (ex. Plant cells)

Prokaryote: Organisms with cells lacking a true nucleus and most types of organelles.(ex. Bacteria)

Isomerism: Molecules of monosaccharides may have the same molecularformula but differ in three-dimensional structures.

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biology notes 1.1-1.2- non ib

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