Nutrients & BiochemNutrients & Biochem

Definition of HomeostasisDefinition of Homeostasis

homeohomeo = same; = same; stasisstasis = standing = standing Homeostasis is the term we use to describe Homeostasis is the term we use to describe

the constant state of the internal environment.the constant state of the internal environment. Homeostasis is a state of Homeostasis is a state of

balance in the body.balance in the body. The processes and activities The processes and activities

that help to maintain homeostasis are referred that help to maintain homeostasis are referred to as to as homeostatic mechanismshomeostatic mechanisms..

THINK!THINK! You are exposed to ever changing You are exposed to ever changing

environmental conditions. For example, you environmental conditions. For example, you may walk out of an air conditioned room into may walk out of an air conditioned room into the hot summer sun. How do you feel? What the hot summer sun. How do you feel? What does your body do to adjust? does your body do to adjust?

How many other examples of homeostasis can How many other examples of homeostasis can you think of?you think of?

For each of your examples, what would happen For each of your examples, what would happen to you if you could not maintain homeostasis? to you if you could not maintain homeostasis?

A Temperature Control A Temperature Control SystemSystem

To help us understand homeostasis in living To help us understand homeostasis in living organisms, let us first look at a non-living organisms, let us first look at a non-living system. We will use a temperature control system. We will use a temperature control system for a room which has many similar system for a room which has many similar features to homeostatic mechanisms…. features to homeostatic mechanisms…. homeostasis animation-temperature controlhomeostasis animation-temperature control

homeostasis animationhomeostasis animation

A ReviewA Review

ExampleExample: thermostatic heating system in a home : thermostatic heating system in a home

Components of an automatic control systemComponents of an automatic control system

VariableVariable is the characteristic of the internal is the characteristic of the internal environment that is controlled by this environment that is controlled by this mechanism (internal temp in this example).mechanism (internal temp in this example).

SensorSensor (receptor) detects changes in variable (receptor) detects changes in variable and feeds that information back to the integrator and feeds that information back to the integrator (control center) (thermometer in this example).(control center) (thermometer in this example).

Example ContinuedExample Continued IntegratorIntegrator (control center) integrates (puts (control center) integrates (puts

together) data from sensor and stored "setpoint" together) data from sensor and stored "setpoint" data (thermostat in this example).data (thermostat in this example).

Set pointSet point is the "ideal" or "normal" value of the is the "ideal" or "normal" value of the variable that is previously "set" or "stored" in variable that is previously "set" or "stored" in memory.memory.

EffectorEffector is the mechanism (furnace in this is the mechanism (furnace in this example) that has an "effect" on the variable example) that has an "effect" on the variable (internal temperature in this example).(internal temperature in this example).

Human Example of Human Example of Negative FeedbackNegative Feedback

Human example: shivering in Human example: shivering in response to cooling of body during response to cooling of body during cold weather or sweating when their cold weather or sweating when their core temperature gets too hot. core temperature gets too hot.

Homeostasis allows an Homeostasis allows an organism to remain in organism to remain in balance with its environment. balance with its environment.

If homeostasis is not If homeostasis is not maintained, it can harm maintained, it can harm or kill the organism.or kill the organism.

High-wire Artist ModelHigh-wire Artist Model

Variable:Variable: position of bodyposition of bodySetpoint:Setpoint: directly over the wiredirectly over the wireSensors:Sensors: nerve receptors nerve receptors

(eyes, inner ears, muscle (eyes, inner ears, muscle stretch receptors, etc.)stretch receptors, etc.)

Integrator:Integrator: brainbrainEffectors:Effectors: skeletal musclesskeletal muscles

High-wire artist uses negative High-wire artist uses negative feedback to maintain relatively feedback to maintain relatively constant position on wire.constant position on wire.

BiochemistryBiochemistry

The study of reactions and molecules The study of reactions and molecules which react to ensure life. which react to ensure life.

Organic compound :Organic compound : molecule that molecule that contains a significant amount of contains a significant amount of carbon C (except CO, COcarbon C (except CO, CO22, and CO, and CO33) ) or hydrocarbon groups. Molecules or hydrocarbon groups. Molecules which have a “skeleton” of carbon which have a “skeleton” of carbon and form an important part of living and form an important part of living cells.cells.

Essential nutrientsEssential nutrients

Fall under two categories: Fall under two categories:

1.1. MacronutrientsMacronutrients

2.2. Micronutrients.Micronutrients.

MacronutrientsMacronutrients

large complex organic molecules large complex organic molecules that must be digested by an that must be digested by an organism in order to be used. There organism in order to be used. There are 4 macronutrients: are 4 macronutrients: carbohydrates, proteins, fats, carbohydrates, proteins, fats, nucleic acidsnucleic acids (nucleic acids will be (nucleic acids will be studied in detail in grade 12).studied in detail in grade 12).

MicronutrientsMicronutrients

small, simple substances that do NOT small, simple substances that do NOT need to be digested by an organism need to be digested by an organism in order to be used. These molecules in order to be used. These molecules are already small enough to diffuse are already small enough to diffuse across a plasma membrane. There across a plasma membrane. There are 3 micronutrients: are 3 micronutrients: minerals, minerals, vitamins & watervitamins & water

1. Carbohydrates1. Carbohydrates

RoleRole : : structural compoundsstructural compounds and as and as energy energy reservesreserves to fuel life processes to fuel life processes - short and long - short and long term. (original source of energy)term. (original source of energy)

Composed of the elements Composed of the elements C, H C, H and and OO in a in a 1:2:11:2:1 ratio. Empirical formula is ratio. Empirical formula is CCmm(H(H22O)O)nn

Carbohydrates (Structure)Carbohydrates (Structure)Subunit (monomer)= Subunit (monomer)=

Monosaccharide or simple sugar :Monosaccharide or simple sugar : Formed of 3 to 7 atoms of Formed of 3 to 7 atoms of carbon. carbon. ex : glucose (ex : glucose (primary energy source for cells), fructose ), fructose (found in some fruit, semen), galactose , galactose (not normally found in nature). .

Disaccharide or double sugarDisaccharide or double sugar: 2 simple sugars together. Ex : : 2 simple sugars together. Ex : sucrose (table sugar) = glucose + fructose, maltose = glucose + sucrose (table sugar) = glucose + fructose, maltose = glucose + glucose, glucose, Lactose (in dairy) = glucose + galactose

Polysaccharide (Polysaccharide (AKA complex carbohydrates):: many simple many simple sugars together. sugars together.

Ex : starch (energy storage in plants), glycogen (energy storage in Ex : starch (energy storage in plants), glycogen (energy storage in animals), cellulose (makes up the cell walls of plants).animals), cellulose (makes up the cell walls of plants).

saccharidesaccharide and the suffix and the suffix oseose refer to sugar. i.e. gluc refer to sugar. i.e. glucoseose or or monomonosaccharidesaccharide..

Monosaccharide

(Monomer)

Disaccharide

Polysaccharide (Polymer)

2. Lipids2. Lipids

RolesRoles : stores nutritive substances and energy  : stores nutritive substances and energy long-term (2,25 times more energy than long-term (2,25 times more energy than carbohydrates), insulation and protections of carbohydrates), insulation and protections of organs, makes hormones et and structural organs, makes hormones et and structural component of the cell membrane. component of the cell membrane.

includes includes fatsfats and and oilsoils, , waxeswaxes, , phospholipidsphospholipids, , steroidssteroids, and some other related compounds., and some other related compounds.

Lipids (Structure)Lipids (Structure)Sub unit (monomer)= Sub unit (monomer)= Glycerol group + 3 fatty acids Glycerol group + 3 fatty acids

Fatty acids can be long, short, saturated (solid), or Fatty acids can be long, short, saturated (solid), or unsaturated (often liquid).unsaturated (often liquid).

All Lipids are All Lipids are hydrophobic hydrophobic (don’t mix with water). (don’t mix with water). Consist of cConsist of carbonarbon,, hydrogen hydrogen andand oxygen oxygen

Lipids Lipids withwith fatty acids fatty acidsTriglycerides (Fats and oils)Triglycerides (Fats and oils)PhospholipidsPhospholipidsWaxesWaxes

Lipids Lipids withoutwithout fatty acids fatty acidsSteroidsSteroids

Lipids (Lipids (Triglycerides)Triglycerides)

Fats (solid at room temperature) and oils (liquid at room temperature) are triglycerides.

Steroids (Sterols)Steroids (Sterols) Compact Compact hydrophobichydrophobic molecules molecules

containing containing fourfour fused hydrocarbon fused hydrocarbon ringsrings

Examples:Examples: Cholesterol-precursor Cholesterol-precursor

to sex hormones andto sex hormones and

vitamin Dvitamin D SexSex hormoneshormones

ProteinsProteins Where do we find Proteins?Where do we find Proteins? What do What do gelatingelatin dessertsdesserts, ,

hairhair, , antibodiesantibodies, , spider webs, spider webs, blood clots, egg whites, tofu, blood clots, egg whites, tofu, and fingernailsand fingernails all have in all have in common? They are all made common? They are all made of protein.of protein.

3. Proteins3. ProteinsRolesRoles :  : Makes enzymes which facilitate chemical Makes enzymes which facilitate chemical

reactions.reactions. Aids transport of substances across the Aids transport of substances across the

cell membrane or in the blood. cell membrane or in the blood. Chemical messengers (hormones), like Chemical messengers (hormones), like

insulin.insulin. The majority of cellular components are The majority of cellular components are

made of proteins. Ex: keratin (hair & made of proteins. Ex: keratin (hair & nails), bone, muscle, tendon, ligament, nails), bone, muscle, tendon, ligament, amylase (enzyme), haemoglobin, etc.amylase (enzyme), haemoglobin, etc.

Proteins (Structure)Proteins (Structure)Sub unit (monomer)= Sub unit (monomer)= Amino acidsAmino acids

Ex : amino acid + amino acid + a.a. + a.a. Ex : amino acid + amino acid + a.a. + a.a. +... = protein+... = protein

Amino acids form polypeptides which form Amino acids form polypeptides which form proteins. proteins.

There are 20 a.a., but only 8 a.a. essential There are 20 a.a., but only 8 a.a. essential (we cannot produce them, must consume (we cannot produce them, must consume them)them)

Amino acids > ProteinsAmino acids > Proteins

(Monomer) (Monomer) (Monomer)

(Polymer)

The Peptide BondThe Peptide Bond Amino acids are bonded together by Amino acids are bonded together by

peptide bonds. peptide bonds. So two amino acids So two amino acids bonded together form a dipeptide. Many bonded together form a dipeptide. Many amino acids bonded together form a amino acids bonded together form a polypeptide.polypeptide.

A polypeptide is many peptides joined together

Complex proteinComplex protein

4. Nucleic4. Nucleic acids acids

RolesRoles : manage growth and development of all  : manage growth and development of all living forms through a chemical code. Determines living forms through a chemical code. Determines characteristics and function of each cell (genetic characteristics and function of each cell (genetic code). code).

Ex: DNA, RNA

Nucleic acids (Structure)Nucleic acids (Structure)

Sub unit (monomer)Sub unit (monomer)= = NucleotidesNucleotides which are formed of a which are formed of a

phosphate group, sugar (ribose or phosphate group, sugar (ribose or deoxyribose) and a nitrogen base.deoxyribose) and a nitrogen base.

Ex:Ex: RNA: single strand of nucleotides RNA: single strand of nucleotides

which contain ribose. which contain ribose. DNA: double strand of nucleotides DNA: double strand of nucleotides

which contain deoxyribose. which contain deoxyribose.

Nucleic acidsNucleic acids

There are 5 nitrogen bases:There are 5 nitrogen bases: AdenineAdenine GuanineGuanine CytosineCytosine ThymineThymine UracilUracil

Nucleic acidNucleic acid

Nucleotide – sub unit or monomer of a nucleic acid

Covalent Bonds: Polar & Covalent Bonds: Polar & Non-PolarNon-Polar

A covalent bond is when A covalent bond is when two atoms two atoms shareshare electrons. This sharing electrons. This sharing holds then together.holds then together.

Some atoms hold onto Some atoms hold onto their atoms more tightly their atoms more tightly than others that is they than others that is they are more are more electronegativeelectronegative..

The relative The relative electronegativities of the electronegativities of the two atoms thattwo atoms that form a form a covalent bond determine covalent bond determine whether or not a bond is whether or not a bond is polarpolar or or non-polar.non-polar.

HH22O: two hydrogen atoms connected to an oxygen O: two hydrogen atoms connected to an oxygen atom by single covalent bonds.atom by single covalent bonds.

Oxygen is more Oxygen is more electronegativeelectronegative than hydrogen than hydrogen (oxygen has a stronger attraction for the electrons of (oxygen has a stronger attraction for the electrons of a covalent bond), so the electrons of the polar bonds a covalent bond), so the electrons of the polar bonds spend more time closer to the oxygen atom. This spend more time closer to the oxygen atom. This polar bond is a result of the polar bond is a result of the uneven sharing of uneven sharing of electronselectrons..

In other words, the bonds that hold together the In other words, the bonds that hold together the atoms in a water molecule are atoms in a water molecule are polar covalent polar covalent bonds.bonds.

The water molecule is a The water molecule is a polar moleculepolar molecule, meaning , meaning the ends of the molecule have opposite partial the ends of the molecule have opposite partial charges.charges.

Polar Molecules

The oxygen end of the molecule has a The oxygen end of the molecule has a partial negative charge, and the partial negative charge, and the hydrogens have a partial positive hydrogens have a partial positive charge charge

Structure of water

HydrolysisHydrolysis

Process by which a large polymers or macromolecules is cut into monomers with the addition of water.

Hydro= water So: Hydrolyse = cut

Lyse = cut with water

Condensation or dehydration Condensation or dehydration synthesissynthesis

Process by which monomers attach together to form large polymers or macromolecules, with the loss of a water molecule.

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