nutrition why do we need to eat? what do we need to eat? what happens to food we eat?

Nutrition

Why do we need to eat?

What do we need to eat?

What happens to food we eat?

Nutrition

Why do we need to eat?

energy

building blocks

calories

macronutrients

micronutrients

Macronutrients

carbohydrates

proteins

lipids (fats)

Micronutrients

vitamins, minerals

Carbohydratesstarches and sugars

most calories for most people

wheat, rice, oats, corn,…

Contain:

Cn(H2O)n

carbon, hydrogen, oxygen

Carbohydrates

building blocks are called:

monosaccharides

aka., simple sugars

e.g., glucose, fructose

Fig. 10-1

Carbohydrates

Put two -saccharides together:

disaccharide

e.g., lactose, sucrose, maltose

Carbohydrates

Put many -saccharides together:

glucose polysaccharides

glycogen

starch

cellulose

Carbohydrates

glycogen

starch

cellulose plant, unbranched

plant, branched

animal, branched

All made from glucose

Why do we need glucose ?

ingestive heterotrophs

cellular respiration

glucose + O2 H20 + CO2 + ATPenergy

Macronutrients

carbohydrates

lipids

lipids (fats, oils, steroids)

molecules that do not mix with water

made of hydrocarbon chains

non-polar

water is polar

HH

O-

+

+

unequally shared electrons

Some other molecules are “polar” and will mix well with water:

hydrophilic

Some molecules are not polar (non-polar) and don’t mix well with water:

hydrophobic

Some lipids are made from fatty acids:

Fig. 10-2


fats and oils

Fig. 10-3


Some are made from cholesterol:

fats and oils

Fig. 10-3


Some are made from cholesterol:

fats and oils

steroids

cell membranes are made of:

phospholipids

Fig. 10-4


phospholipids bilayer

Fig. 10-4


phopholipids

cholesterol

bilayer

Fig. 10-4


phopholipids

cholesterol

proteins

bilayer

Macronutrients

carbohydrates

proteins

lipids (fats)

Proteins:

building blocks are called:

amino acids (20)

e.g., glycine, valine

(8 are essential)

Fig. 10-5

Proteins:

Functions:

structure collagen, keratin

transport through membrane

Fig. 10-4

Proteins:

Functions:

structure

protection

collagen, keratin

antibodies

enzymes DNA Polymerase

transport through membrane

Fig. 10-7

Fiber

not a source of calories

helps “move” stuff through gut

lower blood cholesterol

carbohydrate (cellulose)

Micronutrients

Vitamins (table 10.2)

Micronutrients

Vitamins (table 10.2)

too much (bottom pp. 336 and 338)

too little

diseases

diseases

beri-beri thiamine

a vital aminevitamin

diseases

beri-beri thiamine (B1)

scurvy C

rickets D

Micronutrients

Vitamins

Minerals

Na+, K+, Cl-, Ca++, iron, etc.

“vegetarian” vs. omnivore

plants material are good sources for most nutrients except:

meat-avoiders meat-eaters

balance of amino acids

vitamin B12 (cyanocobalamin)

REVIEW

Chapter 10 Nutrition

A. Human nutritional requirements

– Macronutrients

Carbohydrates, Proteins, Lipids

– Micronutrients

vitamins and minerals

B. Digestive system– Anatomy and chemistry– absorbing nutrients– Cellular respiration

Digestion

chemical breakdown food using enzymes

physically break food into smaller pieces

vs

mechanical

Digestion

Tube from mouth to anus

Fig. 10-8

Fig. 10-9

Chemical reactions:

reactants

enzymeproducts

Protein digestion:

stomach

protein peptidespepsin

(stomach)

Protein digestion:

small intestine

protein peptidestrypsin

(pancreas)

peptides amino acidspeptidase

blood

(small intestine)

Absorption

from “gut” into body

some things diffuse

concentration gradient Fig. 10-11a

Absorption


some things are transported

facilitated transport Fig. 10-11b

Absorption


some things are transported

active transport Fig. 10-11c

Absorption


some large particles are transported

endocytosis

(exocytosis)

Fig. 10-11d



– Macronutrients


– Micronutrients



Production of energy

Remember cellular respiration?

Cellular respiration (includes Kreb’s cycle):

Glucose + O2 CO2 + H2O + ATP (energy)

Production of energy

cellular respiration

three subpathways

glycolysis

Kreb’s cycle

Electron transport chain

Fig. 10-12

Glycolysis split glucose in half

pyruvate gets converted to acetyl-CoA

Other ways to make pyruvate/acetyl CoA

Kreb’s cyclein mitochondria

Glycolysisin cytoplasm

Fig. 10-12

Kreb’s cyclein mitochondria

Glycolysisin cytoplasm

Electron transport chainin mitochondria

Fig. 10-13

three subpathways

glycolysis

Kreb’s cycle

Electron transport chain

use glucose

make CO2

use O2

Cellular respiration

Glucose CO2 (energy)ATP+H2O+O2+

make H2Omake ATP



– Macronutrients


– Micronutrients




C. Circulatory system– Anatomy – distributing nutrients– Cardiovascular disease

D. Malnutrition and Poor health

Circulatory system

Blood

platletswhite blood cells

red blood cellsCells:

(plasma; water, protein, ions, etc.)Fluid

transport O2

immune systemblood clotting

Circulatory system

Vessels

veins

carry blood from heartarteriescarry blood to heart

capillaries exchange of materials

Fig. 10-14

Circulatory system

Heart

4 valves

R + L atria

4 chambers

R + L ventricles

receive blood

pump blood

2 AV valves

2 semilunar valves

Fig. 10-15

Circulatory system

Two circuits

pulmonary

O2-rich blood from left ventricle

systemic

out to the systems of the body

to lungs to exchange gasesO2-poor blood from the right venticle

Figure 10.14 CO2

O2

O2CO2

lungs(air)

cells

externalrespiration

internalrespiration

internalrespiration

Aside on chapter 14 (respiration)

Fig. 14-1

internal vs. external respiration

Where do they occur ?What happens there ?

alveolus

high O2

low CO2

externalrespiration

internalrespiration

high O2

low CO2

low O2

high CO2

low O2

high CO2

cells/tissuesair

low O2

high CO2

high O2

low CO2

Back to chapter 10 (and the heart)

Circulatory system

Heart

Signal to beat comes from withinBeats about 1/second

pacemaker

Has its own blood vesselscoronary vessels

Cardiovascular Disease

Heart and/or vessels

number one cause of death/year

Risk factors:

gendergeneticshypertension

Behavior:

smokingdiet (bad)exercise (lack of)stress

epidemiology

study of disease factors in large populations

AustrailiaNew ZealandUSA

high meat intake

(saturated fats)

high incidence of CV disease

Mediterranean countries

olive oil(unsaturated fats)

lower incidence of CV disease

Japan

Japanese in Hawaii or CA

low consumption of saturated

fats

lower incidence of CV disease

higher consumption of saturated

fats

higher incidence of CV disease

These studies indicate that diet (fats) is more of a factor than genetics (heredity)

Atherosclerosis

Fat deposits in walls of blood vessels

contribute to:

hypertension heart attacks

Fig. 10-16

Lipid transport

Lipids-not soluble in H2OBlood is mostly H2O

Carrier proteins in blood

HDL

LDL

high-density lipoprotein

low-density lipoprotein

Lipid transport



HDL

LDL

carry cholesterol from tissue

carry cholesterol to tissue

Lipid transport



HDL

LDL

“good”

“bad”

ratio(1)

(4)

Malnutrition

povertywareating disorders

“bad nutrition”

Malnutrition

Industrialized nations

obesity

too many calories

too much high-fat food

diet

reduce calorieintake

exercise

increase calories used

+BALANCE

Malnutrition


obesity

anorexia nervosa

“When she weighed 65 kg (140 pounds), Melanie thought of herself as fat and ugly. Her menstrual periods stopped when her weight dropped to 45 kg (100 pounds). Now that she weighs 40 kg (90 pounds), all her friends tell her she is too skinny, but she is sure they are wrong because she still thinks of herself as chubby. She wants to lose even more weight. Melanie has an eating disorder called anorexia nervosa. Her body is not getting the nutrition it needs. She could die the the situation remains untreated.” (BT3, pg. 326)

Fig. 10-17

Malnutrition


obesity

anorexia nervosa

bulimia

BMI body mass index

[ ]weight/height2

pounds/inches2 x 703.7

weight/height2

kg/m2

>=25 overweight>=30 obese

Malnutrition

worldwide:

starvation

too many people

crop failure

political struggle …



– Macronutrients


– Micronutrients




C. Circulatory system respiration

– Anatomy chapter 14– distributing nutrients– Cardiovascular disease

D. Malnutrition and Poor health

nutrition why do we need to eat? what do we need to eat? what happens to food we eat?

Documents

fatty acids

oilssteroids0cell membranes

hydrophobic0some lipids

enzymesphysically break

hydrophilicsome molecules

digestive systemanatomy

good sources

omnivoreplants material