Unit 1 Lecture Review Questions - Human Physiology

For Lecture Exam #1

What is Homeostasis?

At what level of organization does it occur in the human body?

Homeostasis — ability to maintain a constant internal environment

Occurs at both cellular and organismal levels

What happens if cells cannot maintain homeostasis?

How does this affect higher levels of organization in the body?

Cells will die

If cells die, tissues die, organs die, organ system dies, and organisms die

What are some examples of physiological properties that must be controlled?

What happens if they are not controlled?

Some examples are:

• Body Temperature

• pH Level

• Glucose Levels

• Blood Pressure (Blood Volume)

• Nutrients

• Wastes

• Gases (Ex. O2, CO2)

If they are not controlled, can lead to diseases / disorders and even death

What is the purpose of feedback systems?

To detect changes and respond to the changes

How does a negative feedback system work?

How does a positive feedback system work?

What are some keywords to indicate which feedback system is being used?

What are some examples of both feedback systems?

Negative — restores the change back to normal; “returns”; Ex. blood glucose

Positive — enhances the change; “larger, smaller”; Ex. contractions during childbirth

What are the different players in a negative feedback system?

What do each of the players do?

Effector — brings about the desired response to restore the set point of the controlled variable

Controlled Variable — factor held within a narrow range of physiological values; the value that, when changed, sets off the feedback system

Sensor — also called a Receptor; monitors the controlled variable for the set point; when set point is changed, informs the control center of the change

Stimulus — set point that is beyond the desired range

Control Center — also called the Integrator; includes the CNS; compares the actual value to the set point, and sends an error signal if it is different from the set point

What is the order of the players in a Negative Feedback System?

1. Stimulus / Deviation in Controlled Variable

2. (detected by) Sensor

3. (informs) Integrator / Control Center

4. (sends instructions to) Effector(s)

5. (brings about) Compensatory Response

6. (results in) Controlled Variable Restored to Normal

7. (leads to) Negative Feedback System system shut off to relieve Stimulus

What happens during a Dehydration Synthesis reaction?

How does this relate to monomers and polymers?

Is it an Anabolic or Catabolic Reaction?

Does it consume or release energy?

Combines small molecules into larger molecules

Monomers —> Polymers

Anabolic

Consumes Energy

What happens during a Hydrolysis reaction?

How does this relate to monomers and polymers?

Is it an Anabolic or Catabolic Reaction?

Does it consume or release energy?

Breaks down large molecules into smaller molecules

Polymers —> Monomers

Catabolic

Releases Energy

What is Metabolism?

Sum of all chemical reactions that occur within an organism

What are Biomolecules?

Where do we get most of our biomolecules from?

Biomolecules — large macromolecules necessary for life

Get most from what we eat

What are the four forms of biomolecules important for the human body?

1. Carbohydrates (Sugars)

2. Lipids (Fats)

3. Proteins

4. Nucleic Acids / Nucleotides

What is the composition of Carbohydrates?

What are the different types of Carbs? What are they based on?

C:H:O in a 1:2:1 Ratio

Simple Sugars (monosaccharides and disaccharides)

Complex Sugars (polysaccharides)

Types of carbs are based on # of sugar molecules

What is the function of Monosaccharides / Simple Sugars?

What are the three kinds of Monosaccharides?

Function: immediate source of energy

1. Triose

2. Pentose (Ribose and Deoxyribose)

3. Hexose (Glucose, Fructose, and Galactose)

What is the name of the bond formed between two monosaccharides to form a disaccharides?

What type of bond is this?

Glycosidic Bond

Covalent Bond

What is the function of Disaccharides / Simple Sugars?

What are three examples of Disaccharides?

What will always be in a Disaccharide?

How is the energy stored in Disaccharides used?

Function: short-term source of energy

1. Maltose (2 Glucose)

2. Sucrose (1 Glucose + 1 Fructose)

3. Lactose (1 Galactose + 1 Glucose)

Glucose will always be in a Disaccharide

Have to break the bonds to use the energy they contain

What is the function of Polysaccharides / Complex Sugars?

What are three examples of Polysaccharides in the human body?

What are these three Polysaccharides made of?

Function: long-term source of energy

1. Cellulose

2. Starch

3. Glycogen

All three are made up of only Glucose monomers

For the three Polysaccharides:

• What are they made by?

• Are they digestible by humans?

• (Glycogen) Where is it stored?

Cellulose — made by plants, indigestible

Starch — made by plants, digestible

Glycogen — made by animals, digestible, and stored in the liver & skeletal muscles of animals

Explain why corn kernels are not fully digested by our bodies.

The actual corn kernel is made up of Cellulose (indigestible by humans), but the inside is made up of starch (digestible)

Can we break down Starch and Glycogen to use the stored energy?

If so, how?

Yes

Break them down into monosaccharides via Hydrolysis / Catabolic Reactions

Can we store excess Glucose as Glycogen?

If so, how?

Yes

Condense them with Glycosidic bonds via Condensation / Dehydration Synthesis / Anabolic Reactions, to be stored in Liver or Skeletal Muscles

What is the composition of Lipids?

What are the different types of Lipids?

What are the common traits of Lipids?

C:H:O NOT in a 1:2:1 ratio

Triglycerides, Cholesterol, Phospholipids, and Prostaglandins

Hydrophobic, Nonpolar, and make an Emulsion when mixed with water

What is the function of Triglycerides?

How are they structured?

Where are they stored?

Function: long-term source of energy

Composed of 1 Glycerol Backbone and 3 Fatty Acid Chains

Stored in Adipose (Fat) Tissues and the Liver (small amount)

What are Saturated Fats? Unsaturated Fats?

How do saturated and unsaturated fat chains appear?

In what state do both fat types appear at room temperature?

Saturated Fats — contains the maximum # of hydrogens on the carbon chain; no C=C bonds

• Chains stack neatly and fit closely together; straight chains

• Exists as a SOLID @ room temperature (Ex. Butter)

Unsaturated Fats — does NOT contain the maximum # of hydrogens on the carbon chain; contains C=C bonds

• Chains do NOT stack neatly; appear bent / kinked

• Exists as a LIQUID @ room temperature (Ex. Vegetable Oil)

Between Unsaturated and Saturated fats, which is healthier?

Unsaturated fats that exist as liquids at room temperature

What is the function of Phospholipids?

How are they structured?

What is the most important characteristic of Phospholipids that allows it to carry out its main function?

Function: makes up cellular membranes and the Phospholipid Bilayer

Contains a POLAR head (Phosphate Group + Glycerol Backbone) and 2 NONPOLAR Fatty Acid tails

Phospholipids are AMPHIPATHIC

What is the function of Cholesterol?

How are they structured?

What are the two kinds of Cholesterol?

Function: many purposes

Contains 4 interlocking Carbon rings

Low-Density Lipoproteins (LDLs) and High-Density Lipoproteins (HDLs)

Which form of Cholesterol is “good” cholesterol" and which is “bad” cholesterol?

What happens when there is too much “bad” cholesterol in our diet?

“Good” Cholesterol —> HDLs

“Bad” Cholesterol —> LDLs

If we have too many LDLs in our diet, it can lead to plaques in our blood vessels / arteries that limit blood flow

Where can we find Cholesterol?

Why is Cholesterol important in this structure?

Can find it in the Plasma Membrane / Phospholipid Bilayer

Stabilizes and adds fluidity to the Bilayer / Membrane

What are Cholesterol derivatives?

What are the three main Cholesterol Derivatives we talked about? What are their functions?

Products made from Cholesterol

Steroids — hormones

Vitamin D — aid in calcium absorption

Bile — made in the liver; important for lipid / fat breakdown

How are Steroids and Hormones related?

What are some examples of Steroids?

All Steroids are Hormones, but not all Hormones are Steroids

Examples include Cortisol, Aldosterone, and Testosterone

What is the function of Prostaglandins?

How are they structured?

Function: act as signaling molecules in order to cause lots of things to happen (cascades)

Contain 5 Carbon rings and 2 Fatty Acid Chains

What are Cells?

The functional units of the body

What is the function of the Nucleus?

Contains the genetic information of the cell, DNA, which serves as overall genetic info and the blueprints for proteins

What is the function of the Smooth Endoplasmic Reticulum?

Synthesizes Lipids and stores Calcium ions

What is the function of the Cytoplasm?

Consists of the Intracellular Fluid (ICF)

What is the function of the Rough Endoplasmic Reticulum?

Contains Ribosomes on its outside (rough) and is associated with Protein Synthesis via modification of the proteins

What is the function of Ribosomes?

Involved in Protein Synthesis / serves as the site for protein synthesis

What is the function of the Cell Membrane?

Separates the ICF and the ECF

What is the function of the Mitochondrion?

Generates ATP (energy currency) that is used by the cell for energy

What is the function of the Golgi Apparatus?

Packages materials from the Rough Endoplasmic Reticulum into secretory vesicles for transport

What is the function of Lysosomes?

Contain digestive enzymes that break down unwanted materials, such as old organelles or foreign invaders

What is the function of Peroxisomes?

Detoxify materials via Oxidation to turn them into Hydrogen Peroxide, which is then broken down by Catalase into water and oxygen

Materials —> H2O2 —> H2O + O2

What is the function of the Nucleolus?

Manufactures ribosomal RNA

What is the composition of Proteins?

What is the monomer of Proteins?

Composed of C H O N P S

Monomer = Amino Acids

What is the general structure of Amino Acids?

How are Amino Acids differentiated? How many are there?

Why are R groups so important for the properties of Amino Acids?

General Structure:

1. Central Carbon atom

2. Amino Group (—NH2)

3. Carboxyl Group (—COOH)

4. R group

R group in the Amino Acid differentiates the Amino Acids; there are 20 Amino Acids (20 R Groups)

If the R Group of the Amino Acid is polar, the Amino Acid will be polar as well; vice versa applies for nonpolar R Groups

What is the difference between Peptides and Polypeptides for this course?

How are Peptides formed?

Peptides = less than 100 Amino Acids

Polypeptides = greater than 100 Amino Acids

Peptides are formed via Peptide bonds (covalent) between Amino Acids

How are Peptides formed?

How are they broken down?

What bond is formed when Peptides are formed from amino acids?

Formed via Dehydration Synthesis / Anabolic Reactions

Broken Down via Hydrolysis / Catabolic Reactions

Peptide Bonds (covalent)

What are the four structures that influence how proteins fold?

1. Primary (1˚) Structure — linkage / sequence of amino acids via Peptide Bonds

2. Secondary (2˚) Structure — Hydrogen bonds of nearby amino acids

3. Tertiary (3˚) Structure — Attraction / Repulsion of R Groups

4. Quaternary (4˚) Structure — multiple polypeptides linked together

How is Protein function determined?

What are the various functions of Proteins?

Determined by its shape; proper shape = proper function

Functions:

• Enzymes

• Structural Support

• Immunity

• Muscle Contractions

• Transport

• Energy

• Hormones

How can Proteins change shape / function?

By breaking bonds / denaturing and renaturing

What is Denaturation?

What is Renaturation?

Denaturation — loss of biological activity via breaking of bonds

Renaturation — regaining biological activity via reforming bonds

What factors can denature a Protein?

Which two are most common?

pH, temperature, ionic strength, and solubility

pH and Temperature are most common

What is the composition of Nucleic Acids?

What is the monomer of Nucleic Acids?

Composition — C H O N P

Monomer = Nucleotides

What is the general structure of a Nucleotide?

Nitrogenous Base (A, T, G, C, or U)

1 or more Phosphate Groups

Pentose Sugar (Deoxyribose or Ribose)

What are the two groups of Nitrogenous Bases?

How many rings are in each group?

Which nitrogenous bases fit with which groups?

Purines (double-ringed) and Pyrimidines (single-ringed)

Purines — Adenine and Guanine (AGgies are PURe)

Pyrimidines — Cytosine, Uracil, and Thymine (CUT)

What is the energy currency of the cell?

What is the structure of this molecule?

What biomolecules is the energy currency?

Adenosine Triphosphate (ATP) — Nucleic Acid

Contains:

• 3 Phosphate Groups

• Pentose Sugar

• Adenine base (Purine / double-ringed)

What are Nucleic Acids?

Linking of many nucleotides

Compare DNA and RNA characteristics.

DNA (Deoxyribonucleic Acid)

• Make up Chromosomes (carry genetic info)

• Adenine-Thymine and Cytosine-Guanine

• Double Helix / Double-Stranded structure

• Deoxyribose (pentose sugar)

RNA (Ribonucleic Acid)

• Make up Ribosomes, mRNA, tRNA

• Adenine-Uracil and Cytosine-Guanine

• Single-Stranded structure

• Ribose (pentose sugar)

• Involved in Protein Synthesis

As many as 2 million Americans suffer from Mitochondrial disease. What molecule that is important for the body would be affected?

Adenosine Triphosphate (ATP)

If two Hexose sugars were covalently bonded, what type of molecule would be formed?

What reaction must have proceeded in order for this covalent bond to form?

.

What functional group contains —COOH?

What monomer contains this functional group that we know of?

Carboxyl Group

Saturated / Unsaturated Fats

In a healthy individual, the concentration of sugars is kept within a normal range within the body. What is the function of sugars in the human body?

Which player in a negative feedback loop system works to keep the concentration in a normal range?

Sugars are used for stored energy

Integrating / Control Center works to keep the concentration in a normal range

What cellular organelle synthesizes Triglycerides?

What is the purpose of Triglycerides?

Where are they stored?

Smooth Endoplasmic Reticulum

Energy

Stored in Adipose

What is Membrane Transport?

Which directions can membrane transport occur?

Membrane Transport — movement of solutes across the cell membrane

Either from ECF —> ICF or ICF —> ECF

Why is Membrane Transport important?

What are some examples of this importance?

Maintains Homeostasis

Examples:

• Move Glucose into cells to make ATP

• Absorb nutrients across the wall of the guy

What different things are contained in the Phospholipid Bilayer?

Phospholipids, Proteins, Cholesterol, Glycoproteins, and Glycolipids

Describe the main function of Glycoproteins / Glycolipids.

Integral membrane proteins that serve as “identity markers,” allowing cells to recognize other cells

The sugar portion of these proteins are exposed to the ECF

Describe the main function of Channel Proteins.

Transmembrane proteins that allow water soluble solutes to pass through, if the solute is small enough, without needing to undergo a conformational change

Help illustrate Specificity

Describe the main function of Carrier Proteins.

Transmembrane proteins that, when water soluble solutes bind to them, undergo a conformational change to deliver the solute to the opposite side of the membrane

Help illustrate Specificity

Describe the main function of Enzymes.

Integral proteins that can protrude from either the ECF or ICF side of the membrane that aid in catalyzing reactions

Describe the main function of Receptors.

Integral proteins that protrude toward the ECF for ligands to bind to them

What are the three driving forces?

Describe all three.

1. Chemical Driving Force

   • Based on # of particles / [conc.]

   • Always move molecules from HIGH conc. to LOW conc

2. Electrical Driving Force

   • Based on electrical charges

   • Move towards opposite charges / opposites attract

   • Similar charges repel / like dislikes like

3. Electrochemical

   • Combo of Chemical and Electrical

What is another name for Chemical Driving Force?

How do we determine which solution has the highest Chemical Driving Force?

Concentration Driving Force

Base it off the DIFFERENCE in concentrations (NOT THE RATIO!!!)

Using the analogy of bumper cars at a carnival, what concept is described?

Random Thermal Motion

What is Random Thermal Motion?

In what direction do molecules move according to Random Thermal Motion?

Concept that describes how molecules move

Molecules move randomly, colliding and transferring energy, and creating energized stuff or something

Molecules will move to areas of lower energy / fewer molecules

In an excitable cell, what is the net charge in the ICF?

ECF?

What would be the net charge of most neuron cells?

ICF — Negative

ECF — Positive

Most neurons will be -70 mV

What does it mean for the Cell Membrane to be Semi-Permeable / Selectively Permeable?

Why does this occur?

Some solutes freely diffuse across the membrane, while others require a transmembrane protein

Phospholipids are amphipathic; phospholipid bilayer has nonpolar inside area

Which kinds of solutes can freely diffuse across the plasma membrane?

Hydrophobic, lipophilic, nonpolar, and small polar solutes

Which kinds of solutes require a transmembrane protein to cross the plasma membrane?

Hydrophilic, lipophobic, and large polar solutes

What are some examples of chemicals that can freely diffuse across the plasma membrane?

What are some examples of chemical that require a transmembrane protein to cross the plasma membrane?

Freely Diffuse:

• Oxygen, CO2, fat soluble vitamins, fatty acids

Transmembrane Proteins:

• Proteins, Cations, Hydrogen ions, Glucose, amino acids, Anions, Water

What are the properties of Active Transport?

What are the properties of Passive Transport?

Active:

• Not spontaneous

• Requires Energy

• Solutes move against a gradient

• Requires a Transmembrane protein

Passive:

• Spontaneous

• Does not require energy

• Solutes move along a gradient

• May or may not require a transmembrane protein

Using the analogy of a rock and a hill, what are examples of Passive and Active Transport?

Passive — rock on top of a hill, only needing to go down the hill

Active — rock at the bottom of a hill, needing to go up and down the hill

During simple diffusion, what is the direction of movement?

From HIGH to LOW concentration

With / Down / Along the gradient

What kinds of solutes can freely diffuse across the membrane’s phospholipid bilayer?

Hydrophobic, Lipophilic, small polar, and nonpolar solutes

What is Facilitated Diffusion?

During Facilitated Diffusion, what is the direction of movement?

Facilitated Diffusion — form of mediated transport in which the molecule moves passively across the membrane with the aid of a transmembrane protein

From HIGH to LOW concentration, using a TM protein

What kinds of solutes would use Facilitated Diffusion to cross the phospholipid bilayer?

Which direction will these solutes move, in relation to the gradient?

Hydrophilic, Lipophobic, large polar solutes

Along / Down the gradient

What is a Solution?

In this class, what is the solvent and what is the solute in our solutions?

Solution — contains both solutes and solvents

Solvent = H2O / water

Solute = all other ions and molecules besides water

What is Osmosis?

In what direction does water move during Osmosis?

Does Osmosis require a transmembrane protein?

Osmosis — diffusion of water

Water moves from HIGH water conc. to LOW water conc. / LOW solute conc. to HIGH solute conc.

Yes; requires Aquaporins

When water diffuses via Osmosis, what happens to the volume on both sides of the membrane?

One side goes up in volume, while the other goes down in volume

BOTH go up / down the same volume as one another

What is Tonicity?

Specifically, what do we mean when we refer to Tonicity?

Tonicity — behavior of cells when placed in a solution

Specifically, focuses on changes in cell volume by comparing two areas in terms of solute conc. / # of particles

What are the three types of solutions / cells?

How do the concentrations of solutes and water change between the three types?

1. Hypotonic — low solutes, high water

2. Isotonic — equal amounts of solutes and water

3. Hypertonic — high solutes, low water

What happens when a cell is exposed to a Hypotonic Solution?

Water enters the cell, the cell grows / swells, and may burst

What happens when a cell is exposed to a Hypertonic Solution?

Water exits the cell and the cell shrinks / shrivels

Would it be appropriate to describe a cell as Hypo-, Hyper-, or Isotonic?

Are the terms only used to describe solutions?

Yes

No

What are the two types of Active Transport?

What types of molecules / ions do each of the types work on?

Primary (1˚) and Secondary (2˚)

Primary — Inorganic Ions (Na+, K+, Cl-)

Secondary — Organic Molecules (Glucose) and Ions (Na+)

What is the direction of solute movement for Primary Active Transport?

LOW conc. to HIGH conc. (against / up the gradient)

What are the requirements for Primary Active Transport?

Carrier Protein (ex. ATPase, used to hydrolyze ATP) and Direct Energy released via Hydrolysis of ATP

What is the equation for the hydrolysis of ATP?

What happens to the carrier protein in this equation?

ATP + ATPase —> ADP + carrier Protein—Pi + Energy released

The carrier protein is phosphorylated

What are some examples of Primary Active Transporters?

Na+ — K+ Pump

Ca(2+) — ATPase

H+ — ATPase (Proton Pump)

H+ — K+ ATPase