Carbohydrates, Lipids and Proteins(Biological Building blocks)

IB Biology – Assessment Statements 3.2.1 to 3.2.7

Chemistry of Life

Organic chemistry is the study of carbon compounds

Carbon atoms are versatile building blocks bonding properties 4 stable covalent bonds

Organic compounds contain carbon (C) and occur naturally only in the bodies of living organisms.

They almost always contain hydrogen (H), usually contain oxygen (O) and nitrogen (N),

Sometimes contain phosphate (P), sulfur (S), iron (Fe), copper (Cu), sodium (Na), chlorine (Cl) or potassium (K) in small amounts.

Organic and Inorganic Compounds

Assessment Statement 3.2.1

Inorganic compounds do not usually contain carbon. This term is used when referring to any compound that is not organic.

Organic and Inorganic Compounds

Assessment Statement 3.2.1

http://www.slideshare.net/gurustip/organic-or-inorganic-presentation

Carbon molecules can form long chains or rings. Allowing for multiple branches for bonding.

The size and arrangement of organic compounds are unlimited.

Organic compounds are divided into 4 groups: Carbohydrates Lipids Proteins Nucleic acids.

Organic and Inorganic Compounds

Assessment Statement 3.2.1

Complex molecules can be assembled like building blocks.

Hydrocarbons can grow…

Isomers

Molecules with same molecular formula but different structures (shapes) different chemical properties different biological functions

6 carbons

6 carbons

6 carbons

Identify amino acids

Form affects function

Structural differences create important functional significance amino acid alanine

L-alanine used in proteins but not D-alanine

medicines L-version active but not D-version

sometimes withtragic results…

stereoisomersstereoisomers

Form affects function

Thalidomide prescribed to pregnant women in 50s & 60s reduced morning sickness, but… stereoisomer caused severe birth defects

Viva la difference!

Basic structure of male & female hormones is identical identical carbon skeleton attachment of different functional groups interact with different targets in the body

different effects

Macromolecules

Smaller organic molecules join together to form larger molecules

4 major classes of macromolecules: carbohydrates lipids proteins nucleic acids

Our Organic Friends!

Assessment Statement 3.2.2

Made of C, H and O, where the ratio of C to H to O is 1:2:1.

There are monosaccharides, disaccharides and polysaccharides.

Monosaccharides arethe simple sugars. Theirmolecular formula is C6H12O6.

They are single unit sugars.Glucose, fructose and galactose.

CARBOHYDRATESAssessment Statement

3.2.3

Identify Glucose

Assessment Statement 3.2.2

Identify Ribose

Assessment Statement 3.2.2

Most important source of energy – total energy gain is 4 Calories/gram

Carbohydrates are built from sugar molecules (ending in “ose”).

Some famous sugars include: Glucose (found in human blood -#1 brain food), Fructose (plant sugar), deoxyribose (the sugar portion of DNA), Cellulose (a polysaccharide that makes up

plant walls- commonly known as ruffage or fiber).

CARBOHYDRATES

Assessment Statement 3.2.3

Assessment Statement 3.2.6

Disaccharides are double sugars and are made by combining 2 simple sugars together into a two unit sugar. Examples are sucrose, maltose and lactose.

Polysaccharides are long chains of repeating sugar units. Multiunit sugar – more than two sugars combined.

Examples are starch, glycogen and cellulose. Glycogen is stored in animal cells and is often refered to as animal starch. Glycogen is made up of 16 to 24 glucose molecules. The liver converts glycogen into glucose units for energy.

CARBOHYDRATES

Assessment Statement 3.2.3

List one function each for:Glucose, lactose, glycogen in animals:

Glucose = monosaccharide, major energy source for fuelling cellular respiration.

Lactose = disaccharide, energy source found in mammalian milk

Glycogen = polysaccharide; energy storage in liver.

Assessment Statement 3.2.4

Fructose, sucrose and cellulose in plants:

Fructose = monosaccharide: energy component in flower nectar

Sucrose = disaccharide: energy molecule transported via phloem

Cellulose = polysaccharide: major structural component of plant cell walls.

List one function each for:

Assessment Statement 3.2.4

Commonly known as “fat” – total energy gain 9 Calories/gram.

Foods – fish, olive oil, red meat, nuts. Are a key component in cells, especially in the

cell membrane. They are made of C, H and O. Yield twice as much energy as carbohydrates. Lipids are made up of fatty acids and glycerol. 2 types of lipids: saturated and unsaturated.  

LIPIDS

Assessment Statement 3.2.6

Assessment Statement 3.2.6

Structure: Lipids are made up of two portions a glycerol head and fatty acid tails.

glycerol fatty acids

LIPIDS

Lipids can also go through condensation and hydrolsis, just like carbohydrates and proteins.

LIPIDS

3 functions of lipids:1. Energy Storage: lipids provide concentrated

long-term energy storage which can release fuel for cellular respiration as needed.

2. Cell membrane: the main component of cell membraes are phospholipids

3. Thermal insulators: reduce the loss of heat from an organism (e.g. an under the skin layer of lipids).

LIPIDS

Assessment Statement 3.2.6

When an unsaturated fat has only one unsaturated bond, it is known as monounsaturated. When a fat has more than one unsaturated bond it is known as polyunsaturated.

LIPIDS

Assessment Statement 3.2.6

Phospholipids and triglycerides and waxes are three important groups of lipids.

Phospholipids are the building blocks of the fluid mosaic model of the cell membrane. They have a phosphate/glycerol head that is polar and hydrophillic and two fatty acid tails that are hydrophobic.

Triglycerides – are another type of lipid found in the body. These special lipid molecules are built from one glycerol and three fatty acids with the help of an enzyme.

LIPIDS

Saturated Fats Lipids that are solid or semi-solid at room

temperature are said to be saturated (loaded up with covalent bonds to H atoms).

E.g. Butter, shortening and marbling in meat. Saturated fats are very stable at room

temperature.

Unsaturated Fats Lipids that are liquid at room temperature are

said to be unsaturated (containing double bonds, or less H atoms).

E.g. Oil is an example of an unsaturated fat. Unsaturated fats are easier to break down in

the body than saturated fats. Hense the push for people to use vegetable or canola oil rather than butter while cooking.

Lipid Groups Waxes – are the third group of lipids. They are formed

from long chains of fatty acids joining long-chain alcohol or carbon rings. Waxes are insoluble in water, and are used for water proofing plant leaves or animal feathers and fur.

Fats & Diet – stable fats in the body (saturated fats) tend to stay put once ingested leading to plaque in the arteries and ultimately to health complications (e.g. stroke, cancer, high blood pressure, type two diabetes).

Cholesterol – not all fat is bad. Cholesterol is required by the cell membrane and is also important for the production of hormones (specifically sex hormones – estrogen and testosterone). There are two different types of cholesterol in the blood HDL and LDL. HDL is the “good” cholesterol and LDL is the “bad” cholesterol.

Proteins are made of C, H, O and N. They are the most abundant organic compound found in living cells.

The most important macromolecule in the body. Their importance can not be underestimated!

They form: The structural parts nails, hair, cell membrane and

cartilage Pigments (skin, eyes and chlorophyll), Hormones Contractile material of muscle tissues Antibodies Enzymes.

PROTEINS

The building blocks of proteins are amino acids.

The amino acids are bonded together by peptide bonds to form proteins.

The smallest protein consists of 50 amino acids bonded together and the largest consists of over 100, 000.

PROTEINS

Proteins Rule Everything in the Body! Total energy gain is 4 Calories/gram.

(however, energy gain is not their main function).

Your body requries 22 essential amino acids, but can only produce 8! We must rely on digestion to gain the other

amino acids we need. 22 different amino acid groups give rise to an

infinite amount of proteins.

PROTEINS

Proteins are large molecules constructed of many amino acids.

Again, condensation and hydrolysis apply to this macronutrient.

The bond that is formed from an acid group (COOH) and the amino group (NH2) is called a peptide bond. Because of this special bond, proteins are frequently called polypeptides (many peptide bonds).

PROTEINS

Assessment Statement 3.2.5

PROTEINS

Assessment Statement 3.2.2

Shapes – primary (linear), secondary (coiled), tertiary (bent-coiled) and quarternary (compact with a specific structure).

You can unfold a protein (de-nature) by exposing the protein to heat, radiation or a change in pH. (i.e. frying an egg, baking a cake, UV exposure, x-rays).

PROTEINS

PROTEINS Assessment Statement 7.5.1

Primary protein structure: Sequence and number of amino acids Each position occupied by one of 20 amino

acids Linked by peptide bonds

Protein Structure

Assessment Statement 7.5.1

Secondary protein structure: Weak hydrogen bonds between amino and carboxyl groups. Form at regular intervals, creating a regular structure (not

from the interactions between variable R groups) Alpha helix = coiling into a helix Beta pleating = a folded sheet as polypeptide folds back

onto itself. Not all of a polypeptide forms secondary structure in most

proteins.

Protein StructureAssessment Statement 7.5.1

Tertiary protein structure: Interactions between variable R-groups forming Hydrophobic interactions between non-polar amino acids Hydrogen bonds between polar amino acids Ionic bonds between ionic amino acids Covalent bonds between sulfur containing amino acids Producing the three dimensional folded structure of most

proteins.

Protein StructureAssessment Statement 7.5.1

Quarternary protein structure: Aggregations of polypeptides form interactions between

more than 1 polypeptide Polypeptides + non-proteinaceous molecules, such as: Metals, e.g. iron in hemoglobin Vitamins as enzyme co-factors Nucleic acids as in ribosomes Carbohydrates in glycoproteins Lipids in lipoproteins.

http://www.youtube.com/watch?v=lijQ3a8yUYQ

Protein StructureAssessment Statement 7.5.1

Outline the difference between fibrous and globular proteins, with reference to two examples of each type of protein.

Fibrous: Long fibers or sheets formed by parallel

polypeptide chains Dominated mostly by secondary structure Mostly water insoluble Great strength and/or strechiness from affects of

regular H-bonds Collagen in connective tissue Actin and myosin in muscle tissue

Assessment Statement 7.5.2

Outline the difference between fibrous and globular proteins, with reference to two examples of each type of protein.

Globular: Folded into complex 3D irregular spherical shape Dominated mostly by tertiary structure Mostly water soluble Functions determined by 3D shape Enzymes such as amylase Hormones such as insulin Transport such as hemoglobin Protective, such as immunoglobulins

Assessment Statement 7.5.2

Explain the significance of polar and non-polar amino acids Amino acids fit into three groups:

1. Polar2. Ionic3. Non-polar

Assessment Statement 7.5.3

Ionic and Polar amino acids Have hydrophillic R groups Attracting the protein to water Forming H bonds and ionic bonds between

different amino acid R groups Contributing to tertiary structure

Assessment Statement 7.5.3

Non-polar amino acids Have hydrophobic R groups Repelling the protein from water Forming hydrophobic bonds between different

amino acid R groups Contributing to tertiary structure Contributing to protein attraction to fatty

acids in the phospholipid bilayer

Assessment Statement 7.5.3

Polar and Non-polar Amino Acids: The distribution of polar and non-polar amino

acids in a protein determine where in a membrane or cell a protein will be located and the function it will perform.

Assessment Statement 7.5.3

State four functions of proteins, giving a named example of each.

Assessment Statement 7.5.4

Protein FunctionHaemoglobin A protein containing iron that transports O2 from

the lungs to all parts of the body in vertebrates.

Actin and Myosin Proteins that interact to bring about muscle movement (contractions) in animals

Insulin A hormone secreted by the pancreas that aids in maintaining blood glucose level in vertebrates

Immunoglobulins Group of proteins that act as antibodies to fight bacteria and viruses.

Amylase Digestive enzymes that catalyses the hydrolysis of starch.

Metabolism All the chemical reactions that occur in your

body. Approximately 200, 000 chemical reactions occur daily within one single cell.

Catabolic and anabolic reactions are two types of reactions that occur inside the cells.

Catabollic reactions occur when large chemicals are broken down into smaller components.

Anabollic reactions, complex chemicals are built from smaller components.

The chemical compounds of life are made by dehydration synthesis and broken down by hydrolysis. Condensation occurs when molecules bond together by removing a water (H2O) molecule. Enzymes are involved in this type of synthesis. Disaccharides, polysaccharides, lipids and proteins can be made this way. Hydrolysis is the breaking apart of molecules by replacing it with a water molecule at the place where it was removed in dehydration synthesis.

CONDENSATION & HYDROLYSIS

Assessment Statement 3.2.5

H2O

HO

HO H

H HHO

Condensation

Polymers are long molecules built by linking repeating building blocks in a chain by removing water. monomers

building blocks repeated small units

covalent bonds

Condensation!Condensation!

Assessment Statement 3.2.5

H2O

HO

HO H

H HHO

How to build a polymer

Condensation allows for synthesis! joins monomers by “taking” H2O out

1 monomer provides OH–

other monomer provides H+ together these form H2O

requires energy & enzymes

enzyme

Condensation reactionCondensation reaction

Assessment Statement 3.2.5

Condensation builds larger molecules by releasing water

It is an ANABOLIC REACTION Used to build carbohydrates, lipids, and

proteins! Requires an ezyme to act as a catalyst and

speed the reaction along.

Condensation of amino acids to form proteins. http://www2.nl.edu/jste/proteins.htm http://www.biotopics.co.uk/as/aminocon.html

CONDENSATION RECAP

Assessment Statement 3.2.5

Assessment Statement 3.2.5

Assessment Statement 3.2.5

H2O

HO H

HO H HO H

How to break down a polymer

Hydrolysis – aka. digestion use H2O to breakdown polymers

reverse of condensation

Cleaves off one monomer at a time

H2O is split into H+ and OH–

H+ & OH– attach to ends

requires enzymes

enzymeHydrolysisHydrolysis

Assessment Statement 3.2.5

Breaks bonds in larger molecules to produce smaller pieces.

It is a CATABOLIC REACTION Used to break apart carbohydrates, lipids and

proteins. Requires the use of an enzyme to act as a

catalyst and spead the reaction along.

HYDROLYSIS RECAP

Assessment Statement 3.2.5

HYDROLYSIS RECAP

http://www.wisc-online.com/objects/ViewObject.aspx?ID=AP13104

Assessment Statement 3.2.5

CONDENSATION & HYDROLYSIS

Assessment Statement 3.2.5

Assessment Statement 3.2.5

Assessment Statement 3.2.5

Assessment Statement 3.2.5

LIPIDS – saturated vs. unsaturated

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questions! We will return to these questions to discuss your answers at the end.

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Quiz time!

Question 2:

Question 3 and 4

Question 5