Chapter 6: Interactions Between Cells and the Extracellular Environment

- Facilitated diffusion

- Active transport

Identify the methods of carrier-meditated membrane transport

Diffusion

The process of _________ occurs when molecules move down a concentration gradient due to random molecular motion

False

Water in the body occupies two main fluid compartments. Most fluid is in the intracellular fluid (ICF) compartment. ICF is fluid found inside of cells. The rest of our body water is in the extracellular fluid (ECF) compartment. The ECF consists of plasma and interstitial fluid (IF), the fluid in the spaces between tissue cells.

True or False: Most of the fluid in the body is located within the extracellular compartment

- Movement of molecules of an area from a lower concentration to a higher concentration

- Requires expenditure of metabolic energy in the form of ATP

Active Transport

False

True or False: Passive transport requires metabolic energy

Solvent; Solutes

A solution consists of the ________ and ________.

2; In

For every three sodium molecules that are transported out of the cell in the Na+/K+ pump, ______ molecules of K+ are transported ________.

- Passive transport process

- Uses a carrier protein

Facilitated Diffusion

Rate

The ______ of diffusion is dependent upon the surface area and permeability of the membrane, temperature and steepness of the concentration gradient.

Extracellular Matrix

The _______ is compromised by protein fibers and a gel-like ground substance

- Polysaccharides

- Fluid

- Protein

Components that can be found in the extracellular matrix

1. Cytoplasmic calcium binds to the pump

2. ATP is hydrolyzed

3. The carrier protein changes shape

4. Calcium passes through the carrier protein to the other side of the membrane

5. P is realses and the carrier protein returns to its initial state

Steps of the calcium pump in order

Specificity

What is the characteristic, shared by enzymes and carrier proteins, in which the proteins interact only with certain molecules?

Glucose

Which of the following substances will only cross a plasma membrane using facilitated diffusion?

Isotonic

No change in volume will occur in a cell placed in a ________ solution.

- Between adjacent cells

Paracellular transport is the movement of substances:

Selective Permeable

Membranes exhibit _______ in that only some molecules are allowed to pass through the membrane.

Plasma Membrane

What is another name for cell membrane?

- Anchor cells to extracellular matrix

- Relay signals between the cells and the extracellular matrix

What are the functions of integrins?

Osmosis

______ is the specific term referring to the net movement of water across a selectively permeable membrane

- Tight junctions

- Adherens junctions

- Desmosomes

Junctions between adjacent epithelial cells, through which paracellular transport is limited, are

Extracellular

The ________ environment is comprised of fluid compartment containing dissolved molecules and a matrix of polysaccharides and proteins that give form to the tissues.

Aquaporins

________ are special channels that allow the movement of water across a membrane.

Neurons

________ cannot function properly if osmolality is disrupted.

ATP

Primary active transport is directly achieved by hydrolysis of ________.

Paracellular Transport

Junctional complexes allow for:

- Ground substances

- Collagen fibers

- Elastin fibers

Extracellular matrix is comprised of:

False

True or False: Passive transport requires metabolic energy

- Specificity

- Saturation

Choose the characteristics that carrier proteins and enzymes have in common

Blood; Interstitial

Nutrients and oxygen are transferred from the _______ to the _______ fluid.

Osmotic

_______ pressure is the pressure required to halt the process of osmosis.

Transport Maximum

The _____ _____ has been reached when every carrier protein is saturated at the rate of transport cannot increase further

Gated

Some ions move across a membrane using ion channel proteins that are open all the time. Others use _____ ion channel proteins, which have the ability to open and close.

- Na+/ K+

- Ca2+

What membrane transport pumps function through primary active transport?

A. The set point for blood pH is 7.4, so 7.2 is relatively acidotic.

Why is a blood pH of 7.2 considered to be a sign of acidosis?

A. The set point for blood pH is 7.4, so 7.2 is relatively acidotic.

B. A pH of 7 is neutral, 7.2 is greater and is an indicator of increased acids.

C. It is not, a blood pH of 7.2 is considered to be alkalotic.

C. Nonpolar and insoluble in water

Which of the following characteristics are shared by all lipids?

A. Nonpolar and highly soluble in water

B. Have twice as many hydrogen atoms as they do carbon or oxygen

C. Nonpolar and insoluble in water

D. Usually polar and insoluble in water

A. Phospholipid

Which of the following is a polar lipid molecule?

A. Phospholipid

B. Triacylglycerol

C. Micelle

D. Protein

C. Protein

A __ is a structure that can form when phospholipids interact with water.

A. Glycerol molecule

B. Micelle

C. Protein

D. Fatty acid

B. Tertiary

The __ of a protein is/are its three-dimensional structure.

A. Primary

B. Tertiary

C. Amino acids

D. Solubility

D. Triglyceride

The lipid known as __ is the main form of lipid in adipocytes.

A. Fatty anions

B. Cations

C. Disaccharide

D. Triglyceride

B. Monosaccharide - polysaccharide

Glucose is a __ while glycogen is a __ formed from many glucose molecules.

A. Phospholipid -- triglyceride

B. Monosaccharide - polysaccharide

C. Monosaccharide - phospholipid

D. Cell membrane

Which of the following is another term for plasma membrane?

A. Epithelium

B. Epidermis

C. Phospholipid

D. Cell membrane

C. 66%

Approximately what percentage of body fluid is in the intracellular compartment?

A. 75%

B. 20%

C. 66%

D. 33%

C. Exocytosis

During the process of ___ large proteins are moved from the intracellular fluid to the extracellular fluid.

A. Endocytosis

B. Carrier mediated transport

C. Exocytosis

C. Selective permeability

Membranes exhibit__ because only some molecules are allowed to pass through the membrane.

A. Homeostasis

B. Active transport

C. Selective permeability

D. Osmolality

A. Substances bind to membrane proteins and the substance is then transferred across the cell membrane.

Facilitated diffusion and active transport are examples of carrier mediated transport. What does this mean?

A. Substances bind to membrane proteins and the substance is then transferred across the cell membrane.

B. Carrier transport mechanisms require energy, usually in the form of ATP.

C. All of these apply to facilitated diffusion and active transport.

D. Substances using carrier mediated transport are not soluble in polar solvents so must bind to carriers for transport in blood.

B. Osmosis

The term for movement of substances directly through (i.e. into or out of) the cytoplasm of epithelial cells is __

A. Paracellular transport

B. Osmosis

C. Bulk transport

D. Transcellular transport

C. Active transport

A general process of movement of molecules against a concentration gradient using the energy provided by the hydrolysis of ATP is__

A. Hydrolysis

B. Paracellular transport

C. Active transport

D. Facilitated diffusion

B. The shape of the solute

The rate of diffusion through a membrane is dependent upon a number of features of the system. Which of the following DOES NOT affect the rate of diffusion?

A. The permeability of the membrane

B. The shape of the solute

C. The surface area of the membrane

D. The steepness of the concentration gradient

E. The temperature of the solution

B. Most extracellular fluid is interstitial, fluid between cells.

What is interstitial fluid?

A. Fluid in the body

B. Most extracellular fluid is interstitial, fluid between cells.

C. This is another term for blood plasma

D. This is another term for blood plasma

D. Likely, there will be no net osmosis so nothing will happen to the cell

What will happen to a cell if it is placed in an isotonic solution?

A. The cell will lose water by osmosis, and will shrink

B. The cell will gain water by osmosis, and burst

C. The cell will lose water by osmosis and will burst

D. Likely, there will be no net osmosis so nothing will happen to the cell

B. A region of high solute concentration to a region of low solute concentration

In the process of FACILITATED diffusion, solutes will move from__

A. The extracellular fluid to plasma or interstitial fluid

B. A region of high solute concentration to a region of low solute concentration

C. A region of low solute concentration to a region of high solute concentration

D. The intracellular fluid to the extracellular fluid

D. A region of high solute concentration to a region of low solute concentration

In the process of simple diffusion, solutes will move from __

A. The extracellular fluid to plasma or interstitial fluid

B. A region of low solute concentration to a region of high solute concentration

C. The intracellular fluid to the extracellular fluid

D. A region of high solute concentration to a region of low solute concentration

D. ATP is being used to force water and other molecules to cross between cells

What is happening during the process of cotransport?

A. Molecules are passing between cells, not across cell membranes

B. Two or more different molecules or atoms are being moved across a cell membrane.

C. A molecule is binding to a protein and causing the protein to undergo transport

D. ATP is being used to force water and other molecules to cross between cells

True

True or False: Tonicity describes the effect of a solution on the movement of water

B. When oxygen demand increases, the blood vessels in the muscle will widen, bringing in more blood and oxygen.

Muscles are regulated by both intrinsic and extrinsic factors. Which of the following is intrinsic?

A. The energy for muscle contraction is creatine phosphate stored in muscles.

B. When oxygen demand increases, the blood vessels in the muscle will widen, bringing in more blood and oxygen.

C. When a skeletal muscle is required to contract and relax to allow a movement such as walking, the signal for initiating contraction originates in the central nervous system.

D. When you step on a sharp stone, you reflexively contract muscles to avoid pain.

D. Transcellular and paracellular pathways.

Which of the following are ways in which water can move from the digestive tract into the interstitial fluid near blood capillaries?

A. Water is polar so is unable to pass through cell membranes.

B. Mostly transcellular pathways

C. Paracellular pathways only

D. Transcellular and paracellular pathways.

C. Ketosis is a form of acidosis, but her blood pH is probably normal or only slightly acidotic due to homeostatic responses and blood buffers.

One of Angela's goals is to lose weight with a high fat / high protein diet. To measure her success, she tries to get herself into a state of ketosis. This is measured by urine test strips which in her case, shows a pH of 7.0. Urine includes waste, material you are trying to remove from the bloodstream. How is the ketosis affecting her blood pH?

A. Ketosis is a form of acidosis so her blood pH would register as above 7.4.

B. If urine strips show ketosis, her blood pH is probably alkaline, with a pH of 7.6 or lower.

C. Ketosis is a form of acidosis, but her blood pH is probably normal or only slightly acidotic due to homeostatic responses and blood buffers.

D. A blood pH of 7.0 is normal, so she is not experiencing ketoacidosis.

C. It will decrease osmosis by blocking gaps between phospholipids.

How does cholesterol affect the water permeability of a typical phospholipid bilayer?

A. Cholesterol has no effect on cell permeability to water.

B. It will increase osmosis by creating gaps between phospholipids.

C. It will decrease osmosis by blocking gaps between phospholipids.

D. It will decrease osmosis by creating more tight junctions in a cell's membrane

B. Water will have a lower osmotic pressure. Water will have a higher osmotic pressure.

What is the osmotic pressure of fresh water relative to your extracellular fluid?

A. Water and extracellular fluid have the same osmotic pressure.

B. Water will have a lower osmotic pressure. Water will have a higher osmotic pressure.

C. Water will have a higher osmotic pressure.

B. 3 Na+ bind intracellular sites on the transporter, ATP hydrolysis occurs, Na+ is transported across the cell membrane, K+ can then fill 2 binding sites, and are transported into the cell.

Which of the following describes the action of the sodium/potassium Na/K ATPase?

A. 3 Na+ bind intracellular sites on the transporter, ATP hydrolysis occurs, Na+ is transported across the cell membrane, K+ can then fill 2 binding sites, and ATP fills the 3rd site, hydrolysis occurs, and the K+ are transported into the cell.

B. 3 Na+ bind intracellular sites on the transporter, ATP hydrolysis occurs, Na+ is transported across the cell membrane, K+ can then fill 2 binding sites, and are transported into the cell.

C. 2 Na+ and 1 ATP bind three binding regions of the protein facing the extracellular fluid, and 3 K+ bind sites on the intracellular side, transport and ATP hydrolysis occurs

D. 3 K+ bind extracellular sites on the transporter, ATP hydrolysis brings these into the cell, the binding sites now can accept 3 Na+ from the intracellular fluid, and using another ATP, move them out of the cell.

C. Calcium has to be moving down it's gradient from the extracellular fluid to the intracellular fluid.

The movement of calcium ions through calcium channels often results in calcium entering cells. For this to occur__

A. Calcium is moving up it's concentration gradient as it enters the cell.

B. The concentration of calcium inside the cell has to be high, and, the channel has to use ATP hydrolysis to move the calcium.

C. Calcium has to be moving down it's gradient from the extracellular fluid to the intracellular fluid.

D. Calcium has to fit perfectly or nearly so into a binding site, induce a conformational change in the channel protein, and then transport by the channel can occur.

D. Glands are in the dermal layer.

Exocytosis used by certain epithelial structures results in the movement of sebum to the epidermal surface. In which layer of skin is this exocytosis occurring?

A. The basolateral region of the epithelial layer.

B. Sebum is a lipid found in the hypodermis, so that is where exocytosis occurs.

C. Gland open onto the epidermis.

D. Glands are in the dermal layer.

C. They are isotonic to each other, and plasma is about 30% of the ECF.

What is the relationship between blood plasma and extracellular fluid (ECF)?

A. They are isotonic to each other and plasma is about 7-8% of the ECF.

B. Total body water is 1/3 plasma and 2/3 ECF, and plasma is usually hypertonic to ECF.

C. They are isotonic to each other, and plasma is about 30% of the ECF.

D. Total body water is 1/3 plasma and 2/3 ECF, and plasma is usually hypotonic to ECF.

A. Negative feedback counteracts change.

What makes negative feedback responses a process that promotes homeostasis?

A. Negative feedback counteracts change.

B. Negative feedback stimulates a response that will increase the state of a system.

C. Negative feedback lowers the state of a system.

B. Epidermis

Which layer of skin corresponds to the epithelial layer?

A. Hypodermis

B. Epidermis

C. Basodermis

D. Melanodermis

C. Amino acids are often small enough to use carrier mediated transport, but proteins are too large for this.

In the digestive tract, the uptake of proteins and amino acids differs. Which of the following will work for amino acids but will not work for proteins, and why?

A. Because most amino acids and proteins are non-polar, both can use simple diffusion to pass through plasma membranes.

B. Amino acids, depending on their charge, can use channels. Proteins are often uncharged and are not efficiently able to use channels.

C. Amino acids are often small enough to use carrier mediated transport, but proteins are too large for this.

D. Amino acids are usually in high concentration in the GI tract, so are able to use channels, proteins are rare, they are often digested.

B. The Na/K pump.

The SGLT is a symporter that binds both Na+ and Glucose to bring Glucose into a cell. What other membrane protein is required for the SGLE to function in secondary active transport?

A. A GLUT, a glucose channel.

B. The Na/K pump.

C. A Na+/Glu pump that binds with ATP to fuel the pump