Biology Exam 2

Define an Enzyme.

Define an Enzyme.

A biological catalyst that speeds up the rate of chemical reactions in a cell

Which types of biological molecules are enzymes?

proteins or RNA molecules called Ribozymes, which catalyze biochemical reactions.

Which part of the enzyme catalyzes a specific chemical reaction?

The Active Site

• Which part of the enzyme reduces the Activation Energy for a chemical reaction?

The substrate

• What is a Catalyst?

a substance that accelerates biochemical reactions without being consumed by the reactions they catalyze.

Why are biological systems completely dependent on enzymes?

to enable organisms to perform biochemical reactions rapidly, in less than a second, which is required for the existence of life.

Why must your Cells precisely regulate enzyme activity?

To ensure that each enzyme generates the precise concentration of product, at the proper time, and in the proper cellular or extra-cellular location (blood clotting in the blood, for example).

• When do your Cells activate an enzyme?

When the cell needs a specific product.

• When do your Cells inhibit an enzyme?

When it does not need a specific product.

• Why must enzyme regulation be rapidly “reversible”?

To maintain all product levels within their proper concentration range required for proper Cell function.

Describe Competitive Enzyme Inhibition.

interferes with the active site of enzymes so substrates cannot bind.

Describe Allosteric regulation by a Noncompetitive Inhibitor.

changes the shape of the enzyme so it cannot bind to the substrate.

How does a Kinase enzyme rapidly change the activity of other enzymes?

Catalyzes the transfer of y-phosphate from ATP.

• How does a Phosphatase enzyme rapidly change the activity of other enzymes?

Catalyzes the transfer of the phosphate from a phosphoprotein to a water molecule

• What is Phosphorylation?

the addition of a PO4 Group

• What is Dephosphorylation?

is the removal of a PO4 Group

Why do some Predators produce Venom that contains permanent Enzyme Inhibitors in their Prey?

Because those enzyme inhibitors cause immobilization and allow for easy digestion. Think of snakes and spiders and how they eat their prey.

What are enzyme Cofactors?

vitamins and minerals that we get through our diet and must bind to enzymes to activate them.

• Why must our diet contain Vitamins and Minerals for proper enzyme function?

they are cofactors with which enzymes lock the reacting substrate into its respective active site so a reaction can take place.

Why is each enzyme in a specific cellular location or extracellular location?

it performs optimally under the conditions (Temperature, pH, Salt Concentration) of its cellular or extracellular environment.

• What is an example of an enzyme located in the blood?

Vitamin K

What is an example of an enzyme located in the nucleus of your Cells?

Nuclease + protease (involved in apoptosis).

Why is the Cell the most basic biological unit of Life?

because it is the smallest and most fundamental building block of all living organisms. It can acquire energy and process energy independently; repair itself independently; and reproduce independently.

What are the three parts of the Cell Theory?

1) Cells Are the Most Fundamental Units of Life

2) All Single-Cell Species Are Composed of One Cell & All Multi-Cell Species Are Composed of Two Or More Cells

3) All Cells Are Produced from The Reproduction of a Preexisting Parent Cell

• Why aren’t viruses considered the most fundamental units of life?

cannot reproduce, repair, or acquire energy on their own.

Describe why a Cell is as “Complex as the Universe”.

To Function as A Coherent Biological System, The Human Body Requires the Precise interaction Among All Its > 220 Cell Types. 220 different cell types, 60-200 trillion total cells.

Eukaryotes

-Large and complex

-Membrane-bound organelles

-Nucleus

Prokaryotes

-Small and less complex

-No membrane-bound organelles

- no nucleus

• Which internal structures are absent in Prokaryotic Cells?

No nucleus, no membrane-bound organelles

• Which type of Cell typically is larger?

Eukaryotic Cells

Are there more Single-Cell Species or Multi-Cell Species on Earth?

Single-celled species.

Why is each Organelle in a Eukaryotic Cell able to perform a unique set of cellular functions?

Each organelle contains a distinct set of proteins that mediate its unique functions.

• Why does a Eukaryotic Cell require a complete set of functional Organelles?

Organelles serve specific functions within eukaryotes, such as energy production, photosynthesis, and membrane construction.

• Are the Organelles surrounded by one or more Membranes or a Protein Layer?

Yes

Why is each Microcompartment in a Prokaryotic Cell able to perform a unique set of cellular functions?

It has a unique set of enzymes and other chemicals.

• Why does a Prokaryotic Cell require a complete set of fully functional Microcompartments?

Makes a biochemical contribution to cell function.

• Are the Microcompartments surrounded by one or more Membranes or a Protein Layer (Shell)?

surrounded by a protein shell.

What is the source of Human Totipotent Stem Cells?

Human embryo

• What is Human Totipotent Stem Cells unique ability?

Can develop into a complete human body as well as form any of the ~220 human cell types.

Which Human Cell Types can be produced using Totipotent, Pluripotent, Multipotent, or iPS Stem Cells?

220 human cells

• What are the sources of each type of Stem Cell?

totipotent stem cells, pluripotent stem cells, adult stem cells, and pluripotent stem cells produce through genetic engineering technology called Induced pluripotent stem cells (iPSCs).

• What are some medical uses of iPS?

creating replacement body parts

What type of Stem Cell(s) would you use to develop a therapy that could replace any of the 220 Cell Types in the Human Body?

Pluripotent and Totipotent

Why are the Pluripotent Stem Cells in the umbilical cord blood of infants collected at birth and stored?

Helpful in treating a wide variety of malignant and nonmalignant diseases.

What are the medical advantages of cord blood banking?

It contains all the natural elements of blood and is rich in blood-forming stem cells.

What are the functions of Adult Stem Cells in the Human Body?

They Are Strategically Located in Regions of Growth & Regions That Experience Injury to supply the body with new cells.

• Where are Adult Stem Cells located in your Body?

Intestine,Liver, Lung, Muscle, Olfactory Mucosa, Skin, Teeth (In Dental Pulp), Testes

• How could Adult Stem Cell Therapy improve the quality of life?

treat diseases such as leukemia, spinal cord injury, and diabetes.

• What are some potential Adult Stem Cell Therapies?

Anti-aging, Neurological, Cancer, Liver, Kidney, Immune Disorders etc.

• Why is Adult Stem Cell injection into the Body a medical risk?

tumor formation, inappropriate stem cell migration, and immune rejection of transplanted stem cells

What are Organoids?

tiny, self-organized three-dimensional tissue cultures that are derived from stem cells.

What are some practical uses of Organoids?

used to study mechanisms of disease acting within human tissues, generating knowledge and tools applicable to preclinical studies, including drug testing.

• Which type of Stem Cells are used to make Organoids?

Pluripotent and adult stem cells.

• Why are the Stem Cell Niches critical to maintain proper Adult Stem Cell function?

provides an anatomical space to host stem cells but provides signals to maintain the stem cell state.

Where Adult Stem Cells in the Human Body?

“Stem Cell Niches”

Why must multi-cellular organisms precisely regulate Mitotic Cell Division?

by multi-cellular organisms so that the body can reproduce, repair, and replace cells properly.

• When does the Body instruct its Adult Stem Cells to divide (reproduce)?

Whenever a specific type of cell needs to be replaced.

• Why does the Body frequently require a supply of new Cells?

millions of Cells are dying, and they must be replaced.

What is the Cell Cycle?

a series of events that occur in Eukaryotic Cells, resulting in the duplication of the genetic material and the division of the Cell into two identical daughter cells.

What are the Cell Cycles Phases?

Interphase and Mitotic Phase

What is the G0 Phase?

“Quiescent Phase” Or The “Non-Dividing Phase.

Can some Cells in the G0 Phase be instructed to re-enter the Cell Cycle when the Body requires new Cells?

When The Body Instructs an Adult Stem Cell in the G0 Phase to Re-Enter the Cell Cycle, it will enter the Cell Cycle in The G1 Phase.

which phase does the commitment to divide?

G1 (Interphase)

which phase Increase in Size?

G1 (Interphase)

which phase Replicates DNA? Synthesize Nucleotides?

G1 (Interphase)

which phase Makes its final preparations before dividing?

G2 (Interphase)

which phase Divides (reproduce) by Mitotic Cell Division?

M Phase

What is the function of each Cell Cycle Checkpoint?

To verify that essential cellular events were completed accurately.

• Do some cancer cells ignore one or more Checkpoints?

Yes

How do mutations enable cancer cells to ignore one or more Checkpoints?

DNA is damaged and mutations are more likely to occur which disable checkpoints.

What factor would activate each Checkpoint?

Go-Signals

A Checkpoint is activated. How will the Adult Stem Cell respond after the biochemical error is repaired?

the creation of a new cell will continue to the next phase

What is the result of defective Cell Cycle Checkpoints?

Cancer cells and genetic instability.

What is Apoptosis?

programmed cell death

Do some mutations prevent Apoptosis in cancer cells?

Yes

What are some practical applications of Go-Signals like Human Growth Factor?

Stimulates cell growth, differentiation, and tissue repair.

• The Adult Stem Cells must recognize the proper Go-Signal to pass which Checkpoint?

G1/S Phase checkpoint

What are some types of Signals (Ligands) that your Cells must recognize?

• Injury-Related Molecules

• Hormones

• Mechanical Pressure (Touch)

• Neurotransmitters

• pH

• Pathogen (Virus, Bacteria, Fungi, Protozoa) and Parasite (Worm) Molecules.

What are Receptors?

proteins on the cell surface, or inside the cell, that bind to specific Ligands, such as hormones or neurotransmitters and alert the Cell that a specific signal has been recognized.

Which biological molecules serve as Receptors?

• G Protein Coupled Receptors (GPCR)

• Tyrosine Kinase Receptors (RTK)

• Histidine Kinase Receptors

• Ligand-Gated Ion Channel Receptors • Riboswitches (RNA Molecules)

Describe how the G-Protein Coupled Receptors and Tyrosine Kinase Receptors are activated

Enable Your Cells to Recognize Go-Signals & Other Types of Signals (Ligands). The GPCRs Are Required for Cell Cycle Regulation, Immunity, Sensory Stimuli (Olfaction/Smell, Taste, Vision), Hormone, And Neurotransmitter Perception When the Signal Binds to the GPCR, The G Protein Is Activated. The Activated G Protein Alerts the Cell that the Signal Has Been Perceived.

Describe how the G-Protein Coupled Receptors and Tyrosine Kinase Receptors are deactivated.

After the activated G-Protein instructs the Cell to respond to the Signal, the G-Protein must deactivate to prevent abnormal Cell Signaling. The activated G-Protein has the remarkable ability to self-deactivate to stop the Signaling Process.

How can a defective G-Protein cause cancer?

Unregulated G-Proteins That Are Constantly Activated (Constitutive)

How can the Tyrosine Kinase Receptors cause cancer?

They may acquire transforming functions due to mutation and overexpression.

Which type of Receptor is targeted by many Pharmaceuticals?

G-Protein

Where does the Cell place the Receptors that recognize the Hydrophobic signal molecules?

Inside the Cell

Where does the Cell place the Receptors that recognize the Hydrophilic signal molecules?

Outside the Cell

Describe why Signal Transduction is essential for Cell Signaling.

Enable the Cell to Respond Properly to A Signal (Ligand) Recognized by A Receptor

What is the purpose of the Protein Kinase Cascade?

Enables a Single White Blood Cell to Respond Rapidly to A Single Coronavirus Particle Recognized by A Receptor to Prevent Infection & Disease Development