Transcript Chemical Compounds in Cells and in Our Food

Chemical Energy
Review of basic chemistry
• Element – any substance that cannot be broken
down into a simpler substance
– Ex – carbon, nitrogen, oxygen, hydrogen
• Atom – smallest unit of an element
• Compound – two or more elements chemically
combined
– Ex – water, sugar, starch
• Molecule – smallest unit of most compounds
– Ex – H2O, C6H12O6, O2, CO2
Inorganic Compounds
• Don’t contain Carbon, Hydrogen, and Oxygen
– Ex – water (H2O), salt (Sodium chloride), CO2
Organic Compounds
• Contain Carbon, Hydrogen and Oxygen
– Includes:
Carbohydrates
Proteins
Lipids
Nucleic Acids
Proteins
• Contain C, H, O, N and sometimes Sulfur
• Found in many foods
• In the cell, used as: part of cell membranes
structures of organelles
muscles in the body
Structure of Proteins
• Made of amino acids
– There are 20 different amino acids in living
things
• These aa’s link together to form a large molecule of
50-3000 aa’s in one protein.
• Change one aa, changes whole protein
Protein
Enzymes
• Special kinds of proteins
• Chemicals that speed up chemical reactions in the body
without being used up themselves.
• Here the enzyme helps break a large molecule into 2
smaller ones. Some enzymes join two small molecules to
make one larger one.
Enzymes
• Special kinds of proteins
• Chemicals that speed up chemical reactions in the body
without being used up themselves.
• Here the enzyme helps break a large molecule into 2
smaller ones. Some enzymes join two small molecules to
make one larger one.
Carbohydrates
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Energy rich
C, H, and O
Simple sugars - glucose
Complex carbohydrates – made up of many
simple sugars attached to each other
– Starch
– Cellulose – make up plant cell walls
Found in cell membranes, other cell parts, and
store energy
Lipids
• Fats, oils, waxes
• Store energy
• Made of C, H, and O
• Contain more energy
than carbs
Nucleic Acids
• DNA = deoxyribonucleic acid
• RNA – ribonucleic acid
• Made of C, H, O, N, and Phosphorus
• Contain instructions for cells to carry
out all their functions.
Water
• Makes up about two thirds of your body.
• Most chemical reactions occur in water.
• Essential for all life.
Food and Digestion• Why do we need food?
– Material for growth, repair
– Energy
– Allows body to maintain homeostasis
Nutrients – substances in food that
provides body with raw materials and
energy to carry out essential processes
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Carbohydrates
Fats
Proteins
Vitamins
Minerals
Water
Energy
• Carbs, fats and proteins provide body with
energy
• Amount of energy in food measured in
calories
– One calorie is the amount of energy to raise the
temperature of 1 gram of water 1 degree
Celsius
Calorie or calorie?
• Calorie – used to measure energy in foods.
• 1 Calorie = 1000 calories
– Ex – 1 apple contains 50 Calories or 50,000
calories.
– The more calories a food has, the more energy
it contains.
Amount of Calories needed?
• Depends on physical needs and age of the
person
– Very active people need more
– Infants and small children need more
– Older people need fewer
Carbohydrates
• 1 gram carbohydrates provides 4 Calories of
energy
• Provide raw materials to make cell parts
• Two groups:
– Simple carbohydrates
– Complex carbohydrates
Simple Carbohydrates = Sugars
• Found in fruits, vegetables, milk
• Glucose (C6H12O6) – major source of
energy for your cells.
• Another simple sugar = fructose in fruits
Complex Carbohydrates
• Made of many simple sugars connected
• Starch – found in potatoes, wheat, rice, corn
• Fiber (Cellulose) – found in plants, but
cannot be digested and passes through your
digestive system - helps keep things
moving along.
How much carbohydrates do you
need?
• 50-60% of Calories should come from carbs.
• Complex carbs are better to eat than simple carbs –
sugars give a quick burst of energy, but starches are a
longer, more even energy source.
• Foods high in complex carbs usually have other
useful nutrients
• Foods with lots of sugar usually have fewer other
useful nutrients
FATS
• Contain more than 2x
the energy of carbohydrates
• Store energy
• Parts of cells
• Protect internal organs
• Insulate the body
Types of Fats
• Unsaturated Fats
– Liquid at room temprerature
– Oils
– Considered good for you
• Saturated Fats
– Solid at room temperature
– From animals; a few plants –
coconut palm
– Bad for you
Cholesterol
• Saturated fat found in meat, eggs, cheese,
etc
• Necessary for cell membranes in animals
• Not needed in diet; liver makes all that is
needed.
• Can clog arteries and lead to heart attack
How much fat do we need?
• Should have no more than 30% of Calories
in diet from fat
• Should particularly limit intake of saturated
fats and cholesterol
• Read labels – look for palm or coconut oil,
hydrogenated or partially hydrogenated oils
– these are bad for you and you should
avoid them if you can
Proteins in the diet
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For tissue growth and repair
Enzymes speed up chemical reactions
Can be used for energy, but not usually
About 12% of your daily Calorie intake
should be protein
Amino Acids
• The body makes about half the amino acids it needs
• Remainder come from food
• Complete proteins -contain all
of the essential amino acids
– Meat and eggs
• Incomplete proteins – missing
one or more essential amino acid
– Beans, grains, and nuts
Vitamins
• Act as helper molecules for a variety of
chemical reactions in the body.
• The body makes some – K is made by
bacteria in intestine
• The rest come from foods – eating a wide
variety of foods provides all the vitamins
needed.
Types of Vitamins
• Fat soluble vitamins
– Dissolve in fatty tissue and are stored there.
– Excess buildup can be dangerous
– Includes vitamins A, D, E and K
• Water soluble vitamins
– Dissolve in water and not stored in body
– Needed in diet every day.
– Includes vitamins B and C
Fat-Soluble Vitamins
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Vitamin A
Vitamin D
Vitamin E
Vitamin K
Water-Soluble Vitamins
• Vitamin B-Complex
– Thiamin (vitamin B1)
– Riboflavin (vitamin B2)
– Niacin (nicotinamide,
nicotinic acid)
– Vitamin B6 (pyridoxine,
pyridoxal, pyridoxamine)
– Folacin (folic acid)
– Vitamin B12
• Vitamin C
Minerals
• Nutrients not made by living things
• In soil and absorbed by plants
• Body needs 15 minerals for cell
function and structure
• Includes calcium, phosphorus
and iron
• Large amounts can be toxic
Minerals
• Calcium: A mineral important for strong teeth and bones and for muscle and nerve
function. The major mineral constituent of bone.
– sources: milk and milk products, fish with bones that are eaten, turnip and
mustard greens, tofu, almonds and broccoli.
• Chloride: A mineral that regulates body fluid volume, concentration and acid-base
balance. Balance intertwined with that of sodium
• Chromium: A mineral important in regulating blood glucose. sources: brewer's
yeast, whole grains and meats
• Copper: A mineral that is important for nerve function, bone maintenance,
growth, blood formation and utilization of glucose.
– sources: organ meats, sea foods, nuts and seeds
Minerals
• Fluoride: A mineral that is important to dental and bone health. Greatly
improves resistance to cavities
– sources: fluoridated water, foods cooked in or containing fluoridated
water, fish with bones that are eaten, and tea
• Phosphorus: A mineral essential to bone formation and maintenance,
energy metabolism, nerve function and acid balance.
– sources: meat, poultry, fish, eggs, dairy products and cereal products.
• Potassium: A mineral that is essential for nerve function, muscle
contraction and maintenance of normal blood pressure.
- sources: fruits and vegetables.
Vitamin and Mineral
Deficiencies
• Lack of Vitamin D disrupted absorption of
calcium as a child.
Vitamin and Mineral
Deficiencies and Diseases
Vitamin and Mineral
Deficiencies
Toxicity of Minerals
and Vitamins
• High levels of fluoride can be toxic
– Fluorosis
– Kidney Disease
– More harmful to
babies
Water
• People die within days of not having water
• Makes up about 65% of your body weight
• The body’s most important functions take place in
water
• Makes up most of the body’s fluids
• Nutrients are dissolved in water in blood and
transported around the body
• Perspiration
• Need about 2 liter s of water per day
– Need more if weather is hot or your are exercising
Water releases a lot of
heat as it cools. During
freezing weather, farmers
protect citrus crops by
spraying them with
water.
Because it is mostly
water, the filling of a hot
apple pie is much more
likely to burn your
tongue than the crust.
Thermochemistry
Thermochemistry is the study of energy changes
that occur during chemical reactions and
changes in state.
• The energy stored in the chemical bonds of a
substance is called chemical potential energy.
• Heat, represented by q, is energy that transfers
from one object to another because of a
temperature difference between them.
• Heat always flows from a warmer object to a
cooler object.
Energy Transformations
• In an endothermic process, the system gains heat
as the surroundings cool down.
• In an exothermic process, the system loses heat
as the surroundings heat up.
• A system as the part of the universe on which
you focus your attention.
• The surroundings include everything else in the
universe.
• The law of conservation of energy states that in
any chemical or physical process, energy is
neither created nor destroyed.
Heat Flow
• Measured in two common units
1. the calorie
1 cal = 4.184 J
2. the joule
1 J = 0.2390 cal
• The energy in food is usually expressed
in Calories.
• (1 Calorie = 1 kilocalorie = 1000 calories)
Heat Capacity
• Depends on both its
– mass
– chemical composition.
• The amount of heat needed to increase
the temperature of an object exactly
1°C is the heat capacity of that object.
Specific Heat
The specific heat capacity, or simply the specific
heat (“c”), of a substance is the amount of heat it
takes to raise the temperature of 1 g of the
substance 1°C.
q  m  c  Δt
Specific heat typical unit of measure is
degrees Celsius is used!
J
gC
Calorimetry
Calorimetry is the precise measurement of the heat
flow into or out of a system for chemical and
physical processes.
• In calorimetry, the heat released by the system is equal
to the heat absorbed by its surroundings. Conversely,
the heat absorbed by a system is equal to the heat
released by its surroundings.
The insulated device used to measure the absorption or
release of heat in chemical or physical processes is called a
calorimeter.
The heat content of a
system at constant pressure
is the same as a property
called the enthalpy (H) of
the system.
Energy Transformations: Digestion
• Begins in Mouth
– Mechanical – Grinding of food, muscles in mouth
– Chemical - Digestion of starches begins with enzymes in
salivary glands
To Esophagus
Mechanical - Peristalsis – Involuntary
Movement of food through the esophagus
To Stomach
Chemical – Triggered by hormones, Acids and Enzymes
breakdown foods
Mechanical – Stomach churns food into chyme
Electrical – Nerves signal movement of organs
Energy Transformations: Digestion
• To Small Intestines
– Mechanical – Peristalsis moves food , fluid absorption
– Chemical – Pancreatic and Liver Enzymes breakdown
food/chyme
To Large Intestines
Mechanical – Peristalsis and salts and fluid
absorption
To Colon
Mechanical – Wastes are “egested”/ excreted
Task: Energy Transformations
of Digestion
• Choose an organism with a different
digestive system than a human
– Must be complex – not like a sponge or worm
• Draw a flow chart that diagrams the Energy
Process and Transformations
• Use pictures/drawings/ diagrams to enhance
description
• Work must be neat and thorough
THE END