Unit 5: Internal Systems Grade 11 AP Bio

Human composition:

Water 60%

Protein 20%

Minerals 10%

Fat 9%

Carbohydrates 1%

Vitamins <1%

Herbivores

organisms that eat autotrophs (plants & algae)

Carnivores

organisms that eat other animals

Omnivores

Organisms that eat animals & plants

Human vegans are omnivores apparently

4 Required Materials:

Energy

- diet provides fuel for chemical energy, converted into ATP

Growth & repair

- organic carbon + organic nitrogen = organic molecules

- organic = any molecule with carbon

Insulation

- regulates body temperature, shock absorption

Health

- essential nutrients - cannot be produced, must be consumed

Energy

when from food, measured in Joules (J) SI units (Calories)

1 Calorie =

= 4.2 J

1 gram of carbohydrate & protein =

= 16.8 J

1 gram of fat

= 37.8 J

4 Factors That Affect Energy

Age

Gender

Occupation

Climate

Age

Growing children need more energy than elderly

Gender

- men generally need more food that women except for pregnant/lactating female

- the female body is more efficient for energy use

Occupation

Physically demanding occupations require more energy

Climate

Cold climate require more energy for warmth(only applies if actually living outside)

Basal Metabolic Rate (BMR)

the minimum amount of calories required for your body to function

Energy Expenditure Breakdown

Liver 27%

Brain 19%

Other Organs 19%

Skeletal Muscle 18%

Kidneys 10%

Heart 7%

Other requirements for nutrition

Water - for cellular activity

Essential nutrients - help other mechanisms in the body

Fibre - healthy colon

Monomer

basic building block of a repeating chain

Polymer

many monomers attached together

Organic molecule

Covalent compounds composed of carbon atoms in rings/long chains

Attached to other atoms (hydrogen, oxygen, nitrogen)

4 Classes of Essential Nutrients

Essential amino acids

Essential fatty acids

Vitamins

Minerals

Essential amino acids

- Form protein

- Animals require 20 amino acids - 9 are essential for humans

- Must be obtained from food in a preassembled form

Protein deficiency(malnutrition)

caused by insufficient essential amino acids

9 essential amino acids

Threonine

Histidine

Tryptophan

Methionine

Phenylalanine

Lysine

Valine

Leucine

Isoleucine

Valine + Leucine + Isoleucine

30-40% of essential amino acids

Complete protein

A food that has all essential amino acids - meat, eggs & cheese

Incomplete protein

- A food that does not have all essential amino acids

- Most plant proteins are incomplete - specific plant combinations can be combined to get all essential amino acids

- Corn + beans

Protein

Polymer made of amino acids

Essential fatty acids

- some unsaturated fatty acids that must be obtained from the diet

- deficiencies are rare - fatty acids are contained in everything

- Animals can synthesize most fatty acids

Vitamins

- Organic molecules required in the diet in small amounts

- Act as coenzymes in chemical reactions

- Assist in growth and development

- Maintains health of tissue/immune system

# of Essential Vitamins

13

Water soluble vitamins

- Need water to be dissolved and absorbed

- Not stored in large amounts - do not typically cause toxicity/poisonous effects

- Easy damaged by cooking, exposure to air/light

Fat soluble vitamins

- Need fat to be dissolved and absorbed

- Low fat diets are at increased risk of vitamin deficiency

- Stored in the liver and body fat - toxicity can occur if you eat too much

Minerals

Simple inorganic nutrients (required in small amounts, periodic table elements)

Body fluids

- Inorganic & organic

- Stored in cytoplasm, intercellular fluid, blood plasma

- Mostly water

- Can move freely between cells

Inorganic Body Fluid in Humans

water, phosphates, hydrogen ions, sodium ions

Molecular compounds

Atoms share electrons - form covalent bonds

Most are macromolecules - composed of thousands of atoms

Macromolecules

- Raw materials human body need for energy and cellular functions

- Contain essential nutrients

- Fuels body's metabolism

4 Types of Macromolecules

Carbohydrates

Lipids

Proteins

Nucleic Acid

Carbohydrates

Provides materials to build cell membranes & quick energy for use by cells

Monomer: sugar

Examples of Carbohydrates

Glucose

Monosaccharide

Disaccharide

Polysaccharide

Glucose

ring structure when wet, line when dry (always ringed in biology)

Monosaccharide

One sugar (glucose, fructose)

A specific type of monomer for carbohydrates

Disaccharide

two sugars (sucrose, maltose, lactose)

Polysaccharide

Many sugars (starch/cellulose in plants, glycogen in animals)

Enzymes

Many proteins together, usually ends in -ase

Proteins that speed up reactions

Amylase

- A type of enzyme

- Produced in the salivary glands

- Splits large molecules through hydrolysis

Starch

- Digestible polysaccharide made of glucose

- Glucose molecules are linked by glycosidic bonds

Dehydration synthesis

- How plants assemble molecules (glucose)

- Remove H2O to attach two molecules (dehydration + synthesis)

- Formation of a covalent bond between two molecules by a chemical reaction

- Removal of an H atom and an OH group

- Water is produced

- Energy input is required

- Reaction is anabolic

Anabolic Reaction

Larger molecule is created from smaller subunits

Hydrolysis(animals)

- Chemical reaction that results in the cleavage of a covalent bond with the addition of a water molecule

- How animals digest carbohydrates

- Adds an OH and H to each molecule to split them

Lipids

- Stores energy reserves for later use by cells

- Insulates internal organs and builds cell membranes

- Fats, oils, waves

- Broken down by lipases

- ex. Triglycerides

Lipase Example

Pancreatic lipase

- breaks lipids into glycerol & fatty acids in the small intestine

Triglycerides

- Glycerol + 3 identical fatty acid tails

- Bonded through ester linkages

- OH's on glycerol reacts with carboxyls on fatty acids - dehydration synthesis

- Broken by hydrolysis

Proteins

- An amino acid linked by peptide bonds

- Provides structure & support

- Catalysts for chemical reactions

- Provides immunity

- Transports ions and muscle movement

- Insulin, hemoglobin, collagen, antibodies, enzymes

- Broken down by proteases

Protease Example

Pepsin - breaks peptide bonds

Nucleic acids

- Directs growth and development of all organisms

- Composes DNA & RNA

- DNA monomer - nucleotide

- Broken down by nucleases

Nuclease Example

Pancreatic nuclease - breaks nucleic acids

Carbohydrase

Breaks down carbohydrates, produces sugars

Amylase: produced in salivary glands, located in mouth

Lipase

Breaks lipids, creates glycerol + fatty acids

Pancreatic lipase: produced in pancreas, used in small intestine

Protease

Breaks proteins, creates amino acids

Pepsin: produced & used in stomach

Nuclease

Breaks nucleic acids, creates nucleotides

Pancreatic nuclease: produced in the pancreas, functions in the small intestine

Enzyme action

Temperature & pH affects rate at which enzymes function

Pepsin pH level

pH of 0-4

Trypsin pH level

pH of 7-11

Epidemiology

The study of human health and disease in populations

Allows us to understand human nutrition

Ingestion

The act of eating

Suspension Feeders

- Sifting small food particles from the water

- Rely on movement of water to bring them food - do not create their own water currents

- Many aquatic animals are suspension feeders

Substrate Feeders

Organisms that live in or on their food source

Caterpillars

Fluid Feeders

Suck nutrient-rich fluid from a living host

Mosquitos

Bulk feeders

Eat relatively large pieces of food

Rock pythons

Digestion

The process of breaking food down into molecules small enough to absorb

Mechanical digestion

The process of physically tearing material apart

Chemical digestion

The process of enzymatic hydrolysis that splits bonds in molecules with the addition of water

Absorption

The uptake of nutrients by body cells

Nothing is actually in the body until absorption occurs

Elimination/Egestion

The passage of undigested material out of the digestive compartment

Removal of leftover waste

Digestive system =

alimentary canal + accessory organs

Digestive tube

A complete digestive tract/alimentary canal

Can have specialized regions that carry out digestion & absorption in steps

Peristalsis

Rhythmic contractions of muscles surrounding the digestive tract

Sphincters

Valves that regulate the movement of material between compartments

Mechanical Digestion

Where food is broken down and enters the mouth

Salivary glands in the mouth secrete saliva (chemical digestion)

4 salivary glands

Amylase Enzyme

Breaks down carbohydrates (starch) into simple sugars

Broken into oligosaccharide (3-8 rings)

Stomach

Contains gastric juice - salts, enzymes, HCL, water, mucus

Bolus is turned into chyme

Contains pepsin

Chyme leaves stomach through the pyloric sphincter

Absorption - some medicines can be absorbed through the stomach

Pepsin

- Secreted for protein digestion

- Only works at a pH of 2 (HCL is necessary)

- Breaks proteins into small chains of amino acids

- A type of protease

Rugae

Folds in the stomach

Allows stomach to stretch and condense

Pyloric Sphincter

prevents chyme from entering the esophagus and regulates entry into small intestine

Acid (HCl)

Kills off invading bacteria and viruses

Activates pepsin - extremely acidic

Enzymes in the stomach

break down proteins and lipids (chemical digestion)

Mucus

Prevents stomach lining from being eaten away by acid

Goblet cells

Creates mucus in the stomach

Small Intestine (3 parts)

Duodenum

Jejunum

Ileum

Small Intestine Function

Where the majority of absorption occurs

Liver & pancreas helps

Duodenum

Where most digestion occurs

Contains NaHCO3 (sodium bicarbonate, base) to neutralize pepsin & chyme

Where bile enters to emulsify fats

Peristalsis moves chyme along small intestine

Bile (duodenum)

Enters from the gallbladder through the bile duct

Emulsifies fats

Pancreas (duodenum)

Secretes pancreatic juices to reduce acidity of chyme

Responds to hormones in the stomach

Brush border

Epithelial lining of the duodenum

Produces several digestive enzymes

Jejunum

Where the majority of absorption occurs

Contains villi

Villi

- Network of blood vessels & a small lymphatic vessels called a lacteal

- Tiny fingerlike projections

- Increases surface area for nutrient absorption

- Each one has microvilli

- Capillaries - carries blood to absorb nutrients

Lumen

Inside of the intestine

Ileum

Has fewer villi

Compacts leftover into the cecum(into the large intestine)