Jan21 Carbs Lipids

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© 2014 Pearson Education, Inc. Biol 1306

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Biology

Transcript of Jan21 Carbs Lipids

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Biol 1306

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• His body mass index went from 28.8,

considered overweight, to 24.9, which

is normal. He now weighs 174 pounds.

• Haub's "bad" cholesterol, or LDL,

dropped 20 percent and his "good"

cholesterol, or HDL, increased by 20

percent. He reduced the level of

triglycerides, which are a form of fat,

by 39 percent.

• He also took a multivitamin pill and

drank a protein shake daily. And he

ate vegetables, typically a can of green

beans or three to four celery stalks.

• Before his Twinkie diet, he tried to eat

a healthy diet that included whole

grains, dietary fiber, berries and

bananas, vegetables and occasional

treats like pizza.

• "There seems to be a disconnect

between eating healthy and being

healthy," Haub said. "It may not be the

same. I was eating healthier, but I

wasn't healthy. I was eating too much."

• Mark Haub, professor of human

nutrition at Kansas State University

• A man of Haub's pre-dieting size

usually consumes about 2,600

calories daily

• For 10 weeks, he limited himself to

less than 1,800 calories a day

• Ate one of these sugary cakelets

every three hours, instead of meals

• To add variety in his steady stream

of Hostess and Little Debbie snacks,

Haub munched on Doritos chips,

sugary cereals and Oreos

http://www.cnn.com/2010/HEALTH/11/08/twinkie.diet.professor/

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• Observation/question?

• Haub’s hypothesis?

• Prediction?

• Experiment?

• Conclusion?

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Carbon can bond with _______ atom(s).

a. 1

b. 2

c. 3

d. 4

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Carbon can bond with _______ atom(s).

a. 1

b. 2

c. 3

d. 4

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Carbon’s ability to bond with up to four other atoms is significant because ___________.

a. it enables the synthesis of inorganic molecules

b. it allows molecules to assume complex shapes,

and form long chains, rings, and helices

c. all biological molecules have four covalent bonds

d. it leads to the creation of large monomers from

smaller polymers

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Carbon’s ability to bond with up to four other atoms is significant because ___________.

a. it enables the synthesis of inorganic molecules

b. it allows molecules to assume complex shapes,

and form long chains, rings, and helices

c. all biological molecules have four covalent bonds

d. it leads to the creation of large monomers from

smaller polymers

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3.3 What Are Carbohydrates?

Where do you find carbohydrates?

What are carbohydrates?

– Sugars and polymers of sugars

– So then….what is a sugar?

What functions/purposes do carbohydrates serve?

– Energy

– Storage of energy

– A structural part of nucleic acids

– A structural part of some organisms

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3.3 What Are Carbohydrates?

What is a sugar? Some examples…

– Glucose

– Most common sugar in living organisms

– monosaccharide

– Sucrose

– Table sugar

– Disaccharide (glucose-fructose)

– Fructose

– Fruit, honey, corn syrup

– monosaccharide

– Lactose

– Milk

– Disaccharide (glucose-galactose)

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3.3 What Are Carbohydrates?

Polysaccharides are chains of monosaccharides

– Storage polysaccharides include

– Starch, an energy-storage molecule in plants, formed in roots and

seeds

– Glycogen, an energy-storage molecule in animals, found in the

liver and muscles

– Both starch and glycogen are polymers of glucose

molecules

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3.3 What Are Carbohydrates?

Polysaccharides as a structural material

Cellulose (polymer of glucose) is one of the most important structural

polysaccharides

– It is found in the cell walls of plants

– It is indigestible for most animals

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3.3 What Are Carbohydrates?

Polysaccharides as a structural material

Chitin (a polymer of modified glucose units) is found in

– The outer coverings of insects, crabs, and spiders

– The cell walls of many fungi

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Why is it so hard for most animals to break down cellulose?

a. The lipid monomers of this polymer are connected by bonds with unique orientations.

b. It must be eaten with large amounts of fiber.

c. Most animals lack the enzymes that break the bonds between the glucose molecules of this polymer.

d. The high pH of cellulose denatures the digestive enzymes of most animals.

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Why is it so hard for most animals to break down cellulose?

a. The lipid monomers of this polymer are connected by bonds with unique orientations.

b. It must be eaten with large amounts of fiber.

c. Most animals lack the enzymes that break the bonds between the glucose molecules of this polymer.

d. The high pH of cellulose denatures the digestive enzymes of most animals.

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Examples

carrot spinach apple banana

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Examples carrot

spinach

apple

banana

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• Why is it thought that too much sugar is bad for

you?

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• Why is it thought that too much sugar is bad for

you? • Promotes tooth-decay

• Calorie-dense (contains a lot of calories)

• Displaces more nutritious food in your diet

• May increase risk of high blood pressure

• May increase risk of poor lipid (fat) profile

• Increases triglyceride level in blood

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3.4 Where do you find Lipids?

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3.4 Where do you find Lipids?

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3.4 What Are Lipids?

Lipids are classified into three major groups

– Oils, fats, and waxes

– Phospholipids

– Steroids containing rings of carbon, hydrogen, and

oxygen

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3.4 What Are Lipids?

Lipids are a diverse group

of molecules that contain

regions composed almost

entirely of hydrogen and

carbon

– All lipids contain large

chains of nonpolar

hydrocarbons

– Most lipids are therefore

hydrophobic and water

insoluble

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3.4 What Are Lipids?

What are the functions of lipids?

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3.4 What Are Lipids?

Lipids are diverse in structure and serve a variety

of functions

– They are used for energy storage

– They form waterproof coverings on plant and animal

bodies

– They serve as the primary component of cellular

membranes

– Still others are hormones

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3.4 What Are Lipids?

Lipids are classified into three major groups

– Oils, fats, and waxes

– Phospholipids

– Steroids containing rings of carbon, hydrogen, and

oxygen

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3.4 What Are Lipids?

Oils, fats, and waxes are lipids containing only

carbon, hydrogen, and oxygen

– Oils, fats, and waxes are made of one or more fatty

acid subunits

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3.4 What Are Lipids?

Oils, fats, and waxes are lipids containing only

carbon, hydrogen, and oxygen (continued)

– Fats and oils

– Are used primarily as energy-storage molecules,

containing twice as many calories per gram as

carbohydrates and proteins

– Are formed by dehydration synthesis

– Three fatty acids glycerol triglyceride

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Figure 3-12 Synthesis of a triglyceride

triglyceride

fatty acids glycerol

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3.4 What Are Lipids?

Oils, fats, and waxes are lipids containing only carbon, hydrogen, and oxygen

– Fats that are solid at room temperature are saturated (the carbon chain has

as many hydrogen atoms as possible, and mostly or all C–C bonds)

– Examples?

– Fats that are liquid at room temperature are unsaturated (with fewer

hydrogen atoms, and many CC bonds)

– Examples?

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Omega-3 and Omega-6 fatty acids

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Olive oil

Oleic acid is also the primary fatty acid in avocado

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Trans fats

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3.4 What Are Lipids?

Oils, fats, and waxes are lipids containing only carbon, hydrogen, and oxygen (continued)

– Waxes are highly saturated and solid at room temperature

– Waxes form waterproof coatings such as on

– Leaves and stems in plants

– Fur in mammals

– Insect exoskeletons

– Waxes are also used to build honeycomb structures

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3.4 What Are Lipids?

Phospholipids have water-soluble “heads” and water-insoluble “tails”

– These form plasma membranes around all cells

– Phospholipids consist of two fatty acids glycerol a short polar functional group

– They have hydrophobic and hydrophilic portions

– The polar functional groups form the “head” and are water soluble

– The nonpolar fatty acids form the “tails” and are water insoluble

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3.4 What Are Lipids?

Steroids contain four fused carbon rings

– Steroids are composed of four carbon rings fused together with various functional groups protruding from them

– Examples of steroids include cholesterol

– Found in the membranes of animal cells

– Component of male and female sex hormones

– Makes up 2% of human brain

– Excessive cholesterol contributes to cardiovascular disease

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Figure 3-16 Steroids

Estrogen

Testosterone Cholesterol

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Which is NOT a type of lipid?

a. Triglyceride

b. Wax

c. Oil

d. Peptide

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Which is NOT a type of lipid?

a. Triglyceride

b. Wax

c. Oil

d. Peptide

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Assignment

• I will post this assignment and the due date (Mon, Jan 26)

on the “schedule of assignments” file on blackboard

• Find any news article, blog, or advertisement about how

carbohydrates or fat affect health (called article 1)

• Read it

• Find an article supporting or debunking the claim (called article 2)

• Must be from a credible, scientific source

• Turn in a hard copy that contains

• The date, source, article name, author(s) of article 1

• One to three bullet points describing the claim in article 1

• The date, source, article name, author(s) of article 2

• One to three bullet points about how article 2 supports or debunks the claim in article 1