Reading 2 - Human Physiology

Chapter 3: Cells and Biomolecules (Part 1)

What are the four types of organic compounds that are most important to human structure and function?

1. Carbohydrates

2. Lipids

3. Proteins

4. Nucleotides

How many valence electrons are in the valence shell of a carbon atom?

How do they complete their valence shells?

4 valence electrons

Complete their valence shells by covalently bonding and sharing electrons with other atoms

What is the carbon skeleton?

Long carbon chain

Which element does carbon always share electrons with?

What are groupings of Carbon and this element called?

Hydrogen

Hydrocarbons

What are the five functional groups that are important in human physiology?

1. Hydroxyl ( —OH )

2. Carboxyl ( —OCOH )

3. Amino ( —NH2 )

4. Methyl ( —CH3 )

5. Phosphate ( —PO4^2-)

Describe the importance of the five functional groups most important in human physiology.

1. Hydroxyl — polar components of all four organic compounds; involved in dehydration synthesis and hydrolysis reactions

2. Carboxyl — found in Fatty Acids, Amino Acids, and other acids

3. Amino — found in Amino Acids

4. Methyl — found in Amino Acids

5. Phosphate — found in Phospholipids and Nucleotides

What kind of molecules are the four organic compounds in this chapter?

How are the molecules structured?

Macromolecules

Structured from monomers covalently linking together to form long polymers

How are monomers formed into polymers?

How are polymers broken down into monomers?

How do the monomers all contribute?

Dehydration Synthesis — releases a molecule of water

Hydrolysis — bonds are broken via donation of a water molecule

In Dehydration Synthesis, one monomer gives up a Hydrogen and the other gives up a Hydroxyl group

In Hydrolysis, one monomer take a Hydrogen atom and the other takes a hydroxyl group from the molecule of water

What is the First Law of Thermodynamics?

Energy cannot be created nor destroyed— it can only change form

What is the basic function of us as an organism?

What two types of reactions help us accomplish this?

What is the name for the sum of these two reactions?

To consume energy and convert it into fuel to sustain our bodies and their functions

Anabolism and Catabolism

Metabolism

How can we easily remember Anabolism and Catabolism?

How do they occur?

Anabolism —> Add, from SMALL to LARGE

Catabolism —> Catastrophe, from LARGE to SMALL

Occur simultaneously and continuously

What compound is used to store and release energy?

How is it used?

ATP (Adenosine Triphosphate)

Cell stores energy in the synthesis (ANABOLISM) of the ATP, the the ATP is broken down (CATABOLISM) to release energy for the cell to use

What is a Carbohydrate?

What is the generic formula for a molecule of a carbohydrate?

Molecule composed of a carbon, hydrogen, and oxygen

Generic formula is (CH2O)n

What are Carbohydrates referred to as?

What three forms are most important for the human body?

Saccharides

Monosaccharides, Disaccharides, and Polysaccharides

What is a Monosaccharide?

What five monosaccharides are important?

Which of the five are Hexose sugars and which are Pentose sugars?

Monomer of carbohydrates

Glucose (H), Fructose (H), Galactose (H), Ribose (P), and Deoxyribose (P)

What is a Disaccharide?

What three disaccharides are important?

How are these disaccharides used by the body?

Pair of monosaccharides

Sucrose, Lactose, and Maltose

Because they cannot be used directly, they are split into their component monosaccharides via hydrolysis

What are Polysaccharides?

What three polysaccharides are important?

Polymers that can contain a many monosaccharides

Starches, Glycogen, and Cellulose

What form do the three important polysaccharides take?

Where are they found?

Are they easily digestible?

Starches — polymers of glucose, occur in long chains (Amylose) or branched chains (Amylopectin) that are stored in plant-based foods that are easily digestible

Glycogen — polymer of glucose, stored in the tissues of animals (muscles and liver)

Cellulose — primary component of the cell wall in green plants, referred to as fiber; not digestible in humans

How is excess Glucose stored in the human body?

Stored as Glycogen in the muscles and liver

How do our bodies obtain Carbohydrates?

Through plant-based foods

What cells in the body can use glucose?

What cells can only use glucose?

All body cells can use Glucose

Nerve cells and red blood cells can only use Glucose

What is produced when glucose is broken down for energy?

What is this product composed of?

How does this product create energy for the cell?

ATP

Ribose sugar, an Adenine base, and three phosphate groups

When the phosphate bonds are broken, energy is released

What is the relationship between oxygen presence and ATP production?

In the presence of Oxygen, more ATP is produced than in pathways that do not utilize Oxygen

What is the overall reaction for the conversion of the energy in glucose into energy in ATP?

C6H12O6 + 6 O2 —> 6 CO2 + 6 H2O + ATP (1)

What is formed when a carbohydrate bind to a protein? A lipid?

Where are these two products found?

Glycoprotein, Glycolipid

Both are found in the membrane enclosing the contents of body cells

Where are oxygen atoms typically located at in Lipids?

The periphery of the molecule

Are lipids hydrophobic or hydrophilic? Why?

When mixed with water, what type of solution is formed?

Hydrophobic, because the hydrocarbons present in the lipids are hydrophobic

An emulsion (mixture of solutions that do not mix well)

What are Triglycerides?

How are they formed?

What are the two types of molecules that form a Triglyceride like?

One of the most common dietary lipid groups that are found most abundantly in body tissues

Formed via the synthesis of a Glycerol backbone and three fatty acids

Glycerol backbone — consists of three carbons

Fatty Acids — long chains of hydrocarbons with a carboxyl group and a methyl group at opposite ends, extending from each of the carbons of the glycerol

What reaction forms Triglycerides?

How does this reaction carry out?

How many water molecules are involved in this reaction?

Dehydration Synthesis

Glycerol gives up H atoms from its hydroxyl groups at each bond, and the carboxyl group on each fatty acid chain gives up a hydroxyl group

Three water molecules are released