Test 2

• Can you list/describe the functions of the plasma membrane?

• Protection for the cell

• Gives the cell its shape

• Regulates transport in and out of the cell

• Prevents entry of harmful materials

• To be semi-permeable

• What are the major properties that affect a molecule’s ability to cross the cell membrane?

• Size

• Charge/polarity/lipid solubility

• Can you list/describe the major characteristics of channel proteins?

• Hydrophilic channel (small molecules or ions use as a tunnel)

• Aquaporins (for passage of water)

• “gated” channel (gate that opens or closes)

What is cystic fibrosis

• A genetic disorder where Cl- can not get through the membrane

Where does cystic fibrosis occur?

A channel protein

Can you describe the major characteristics and functions of carrier proteins?

• Transport molecules across the membrane by conformational change (shape change)

  • Specific to the type of molecule being transported

Can you describe the major characteristics and functions of receptors?

• Recognize + bind to specific molecules based on specific 3D structure

  • Lock-and-key binding

Can you describe the major characteristics and functions of docking-maker acceptors?

• Specialized proteins (on inner cell membrane), t-SNAREs, bind with v-SNAREs, results in secretion of vesicle into ECF

Can you describe the major characteristics and functions of membrane-bound enzymes?

• On inner or outer surfaces, control rate of specific chemical reactions

Can you describe the major characteristics and functions of CAMs?

• On inner or outer surfaces, control rate of specific chemical reactions

  • Stick out from cell surface, hold adjacent cells together, link cell membrane to cytoskeleton, relay regulatory signals through membrane (messenger)

Can you describe the major characteristics and functions of self-recognition proteins?

• Major histocompatibility complex, recognize self from non-self, important in immune response

  • Think organ transplant rejection or autoimmune disorders

• What is an MHC (major histocompatibility complex)?

A self-recognition protein

Why is the Major Histocompatibility complex (MHC) so important?

• recognizes self from non-self (immune responses)

  • autoimmune disorders, organ rejection

What are adhering junctions?

Desmosomes

How do adhering junctions differ from tight and gap junctions?

• Hold 2 adjacent, non-touching cells together

• In tissues that stretch

Examples of adhering junctions

skin, uterus, heart

Examples of tight (impermeable) junctions

digestive tract

Examples of gap (communicating) junctions

cardiac & smooth muscle

What is passive transport?

• Substances diffuse down a concentration gradient

• No energy required

What is active transport?

• Substances move across membranes against their concentration gradient

Describe the process of diffusion

• A passive transport, spontaneous movement, no energy required

Describe the process of osmosis

diffusion of water

Describe the processes of mediated/facilitated transport

• Passive movement across the membrane with the aide of a carrier or channel protein.

In Fick’s Law of Diffusion, the net rate of diffusion across the membrane is directly proportional to—-

• Substance’s concentration gradient

• How permeable the membrane is to the substrate

• Surface area of the membrane

In Fick’s Law of Diffusion, the net rate of diffusion across the membrane is indirectly proportional to—-

• Substance’s molecular weight

• Distance must travel to cross the membrane

What is a symport mechanism?

• Transport of 2 or + molecule types in the same direction (Na+/Glucose pump)

What is a antiport mechanism?

• Transport of 2 or + molecule types in the opposite direction (Na+/K+ ATPase pump)

What is primary active transport?

• Energy directly required to move a substance against its concentration gradient

What is secondary active transport?

• Energy required for the overall process, not directly required to run the pump (uses ion concentration pump)

Examples of primary active transport

Sodium Potassium pump

Examples of secondary active transport

Ion concentration gradient (Maybe????)

• What is “non-shivering thermogenesis”? 

• The generation of heat by chemical means without muscle contraction (shivering)

• How is brown adipose tissue (BAT) involved?

• BAT has a “heat producer” protein, thermogenin, that allows for  thermogenesis

• Newborns can’t shiver and must use BAT 

• Can you describe how mitochondria associated with this adipose tissue generate heat?

• Thermogenin (the heat producing protein) uncouples the ETC from the process of generating ATP

• Stops the ETC from producing ATP to instead make heat.

• What is fermentation? 

When oxygen is not available to form ATP.

• Can you describe the similarities in alcoholic and lactate fermentation? 

• Both used for edible things, go through similar formation processes, both have a pyruvate converted.

• Can you describe the differences in alcoholic and lactate fermentation? 

• Alcohol produces CO2 Lactic does NOT

• Which process normally occurs in your muscle cells? 

• Lactic acid fermentation

• What is the ultimate goal of these processes? (fermentation)

• To generate ATP to keep glycolysis going even with a lack of oxygen.

• During anaerobic respiration, how is creatine phosphate (PCr) involved in energy production? 

• Muscles store this high-energy phosphate in these molecules

  • Part of what is broken down in Lactic acid fermentation to produce ATP

  • PCr + ADP —> ATP + Creatine

What is the end product of lactate fermentation?

Net 2 ATP and lactate

How does your body deal with the end product of lactate fermentation?

• Lactate gets sent through the bloodstream to the liver to be converted back to glucose (gluconeogenesis)

• Why do your cells undergo anaerobic respiration (i.e. is it worth it energetically? – explain).

• When there is not enough O2 to perform aerobic respiration

• It is not very efficient

  • O2 is needed for ETC to work

  • No O2 ETC & oxidative phosphorylation stop

  • = no energy to power proton pumps

• Is glucose the only “crude fuel” that cells use for cellular metabolism? 

NO!

• At what point(s) do fatty acids enter cellular metabolism?

• Used in the citric acid cycle (KREBS)

  • Fats (monomer?) are digested in glycerol (used in glycolysis)

• At what point(s) do amino acids enter cellular metabolism?

• Enter before glycolysis & used for KREBS

How much ATP may be produced by a gram of fat vs. a gram of carbohydrate?

• 1g of fat produces more than twice as much ATP as 1g of a carbohydrate.

• What is metabolic rate? 

• Energy expenditure/unit of time

what is a calorie?

• basic unit of heat energy

• amount of heat required to raise temp. of 1g of H2O by 1 degree C

What is a Calorie?

• Used when discussing the human body

• Equivalent to 100 calories

• Describe BMR.

• Rate of energy conversion in mental & physical rest in a thermally neutral environment while in a fasting (postabsorptive) state.

• Can you list and describe two ways to measure metabolic rate?

Direct calorimetry and indirect calorimetry

Describe direct calorimetry

• Closed chamber with water circulating through walls

• Measure total amount of heat produced per unit time

• Dif. Temp. of water leaving chamber reflects amount heat liberated by the person.

Describe indirectly calorimetry

• More convenient

• Measures O2 uptake per unit of time

• During aerobic oxidation – amount heat produced is directly proportional to amount oxygen consumed

• What is the general function of muscle tissue? 

• Contraction and force generation

Describe skeletal muscle tissue

• Rode shaped fibers

• Attach to bones by tendons

• Move skeleton

• Striated, voluntary

Describe smooth muscle tissue

• Spindle shaped fibers

• Control movement of substances through hollow tubes & organs

• Not striated

• Involuntary

Describe cardiac muscle tissue

• Only in the heart

• Branches cells connected by intercalated disks

• Striated

• involuntary

• What is connective tissue?

• Tissues that connect, support, anchor

• Structural proteins

• Specialized glycoproteins

• Proteoglycans

• Can you identify/describe examples of connective tissue?

• Loose (holds organs in place)

• Tendons/ligaments (dense)

• Bone

• Cartilage

• Blood adipose

What are neurons?

• Functional unit of nervous system

• Dendrites, soma (cell body), axon, terminal bulbs

• Define a tissue.

• A cooperative unit of similar cells that perform one or more specific functions.

• Can you identify and describe the 4 major tissue types found in the human body?

• Epithelial

  • Sheets that line tubes/cavities or cover the body

  • Composed of many glands (exocrine or endocrine)

• Muscle

  • Cells (fibers) specialized for contraction & force generation

• Connective

  • Connects, supports, anchors

• Nervous

  • Initiation/transmission of electrical impulses

• How, specifically, is epithelial tissue named? 

• Layering (simple, stratified, pseudostratified)

• Shape (cuboidal, columnar, squamous)

What are neuroglia?

• nerve glue”

• Astrocytes, oligodendrocytes, microglia, ependymal cells

What is the primary function of the digestive system?

• Transfer nutrients, water, electrolytes from ingested food to cells of the body

Describe the general anatomy of the digestive system.

• A tube with two openings (mouth + anus) & many specialized sections (alimentary canal)

What is a lumen?

• A cavity of a tubular or other hollow structure

• Is the material within the lumen of this tract really inside the body? Why?

• No, because nutrients are not part of the body until they are absorbed in the blood or lymph

• How is the digestive system a hostile place?

• There is a gastric acid with a pH of ~1-2

What are the main processes that occur in the digestive system?

• Ingestion

• Motility

• Secretion

• Digestion

• Absorption

• Elimination

Describe the process of ingestion

• Taking in food to the digestive system

Describe the process of motility

• Move material through digestive tract (done by  smooth muscles in walls of tract)

• Tone (low level state of steady contraction)

• Mixing (exposure for chemical digestion + absorption)

• Propulsion (moving material through tract)

Describe the process of secretion

• Release specific materials by cells/glands of digestive tract

Describe the process of digestion

• Chem. + mech. Breakdown of ingested items into smaller units

Describe the process of absorption

• Active or passive transfer of nutrients across the epithelium to the blood or lymph

Describe the process of elimination

• Removal of undigested and/or unabsorbed materials from the body

What are the 4 major tissue layers of the digestive tract

• Mucosa

• Submucosa

• Serosa

• Muscularis externa

Define the Mucosa

• Innermost layer facing the lumen

• Highly folded

• Mucous membrane (epithelial cells)

• Lamina propria (loose connective tissue, small blood & lymph vessels, nerves)

• muscularis mucosa (smooth muscle)

Define the submucosa

• Thick layer of connective tissue (w/ elastin fibers)

• Larger blood, lymph vessels & nerve network (submucosal plexus)

Define the serosa

• Thin, membranous outer layer of conn. Tissue

• Secretes serous fluid (slippery lol) prevents friction between digestive organs + surrounding tissues

• Continuous w/ mesentery peritoneum

Define the muscularis externa

• major area of smooth muscle (inner circular + outer longitudinal) that allows for gut movement/contraction

What is a hernia?

• Part of an internal organ or tissue bulges through a weak area of muscle

What is mastication

• When food is crushed and mixed with saliva to form a bolus for swallowing

What are salivary glands?

• Glands in the mouth that produce saliva

What is saliva composed of?

• ~99% water

• Electrolytes & proteins

• Bicarbonate (HCO3-)

• Mucus

• Lysozyme

• Salivary amylase

Chemical digestion of what type of molecule begins in the mouth? 

Carbohydrates

What enzyme is involved in the chemical digestion of carbohydrates in the mouth?

Salivary amylase

What is a lysozyme?

• Breaks down some bacteria, an enzyme

• What is the pharynx? 

• Common area w/ tubes leading to the lungs and stomach

Can you describe how swallowing a bolus of food occurs? 

• Deglutition (swallowing)

• All-or-none reflux

  • can be voluntary (Bolus gets pushed into the pharynx)

  • Involuntary muscle contraction moves food into esophagus

What happens if the process of deglutition (swallowing) does not work correctly?

• Food goes into the nasal passages, choking (blocking of the airways)

What is the function of the mucus secreted by the esophagus?

Motility

What is peristalsis?

•  Wavelike contractions of circular + longitudinal muscles, moving bolus toward stomach

What are the three specific parts of the stomach?

1. Fundus

2. Body

3. Antrum

Describe the fundus part of the stomach

• Thin wall, gastric pits (contains secretory cells)

• Top

Describe the body part of the stomach

• Rugae (extensive folding of mucosal lining)

• Middle

Describe the antrum part of the stomach

• Thickest part of the stomach

• Bottom

What is retropulsion and how does it occur

• Chyme (bolus once it enters the stomach) is mixed back & forth & churned into a liquid mixture

What is gastric reflux?

Stomach acid that gets into the esophagus