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Pathophysiology > Chapter 3: Cell Structure and Function > Flashcards

Chapter 3: Cell Structure and Function Flashcards

1
Q

Cytoskeleton

A

A protein network that maintains the cells shape, allows cell to move, and directs movement of substances within the cell

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2
Q

What is the cytoskeleton composed of?

A

Proteins such as actin filaments, microtubules, intermediate filaments

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3
Q

Nucleus

A
  • Contains DNA (genes —> proteins)
  • Controls the cell by regulating proteins synthesis (controls what proteins the cells needs to make)
  • Proteins made by cells can function as enzymes, be structural components of the cell part of membrane receptors or serve other functions
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4
Q

Ribosomes

A

Part RNA and part proteins

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5
Q

What is the role of ribosomes and where can we find them in the cell?

A
  • This is where proteins synthesis occurs.

- We find ribosomes in the cytoplasm of the cell OR on the rough ER

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6
Q

Endoplasmic reticulum

A

Interconnecting membrane network within cell includes rough ER and smooth ER

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7
Q

Rough ER

A
  • Contains ribosomes which are the site of protein synthesis
  • Used for making proteins that will be exported out of the cell or will become part of the cell membrane
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8
Q

Smooth ER

A

Lacks ribosomes and is the site of lipid metabolism for storage of calcium ions (muscle cells)

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9
Q

Golgi apparatus

A

Modifies and packages proteins and lipids into vesicles for transport

the UPS of cells

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10
Q

Lysosomes

A

Vesicles formed by the Golgi that are filled with hydrolytic enzymes

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11
Q

What types of cells do we find lots of hydrolytic enzymes?

A

Neutrophils and macrophages (phagocytosis)

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12
Q

Mitochondria

A

Organelle that converts chemical energy into the form of ATP energy

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13
Q

Aerobic Respiration

A
  • Occurs in mitochondria

- Reaction where energy of glucose and other food molecules are converted into ATP (requires oxygen for final step)

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14
Q

True for False:

ATP is a stable molecule that can be stored for later expenditure in the cell.

A

False

ATP must be continuously synthesized, therefore if the cell is deprived of oxygen it cannot make sufficient ATP to meet its energy demands, so the cell dies.

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15
Q

Plasma membrane

A

A phospholipid bilayer surrounding cells

Is embedded with proteins that perform many of the membranes functions

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16
Q

List the functions of the plasma membrane.

A
  • Regulates what gets into or out of the cell
  • Generates membrane potential
  • Cell to cell recognition (WBC, antigens, glycoprotein…)
  • Communication between cells (Nervous & endocrine)
  • Sensor to environment (enables cell to sense environment)
  • Growth (cell division) regulation (mitosis/neoplasia)
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17
Q

Simple diffusion

A

Occurs when molecules freely across the plasma membrane

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18
Q

What kind of molecules pass through the PM via simple diffusion? Why can they pass so freely?

A

Small, lipid soluble (nonpolar) substances.

They can pass through because they are nonpolar just like the hydrophobic inner layer of the plasma membrane

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19
Q

List molecules of simple diffusion

A

Steroids, gases (O2 & CO2), and alcohols

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20
Q

True or False:

Simple diffusion does not require energy or carrier proteins.

A

True; they flow down the concentration gradient

flow from high concentration to low concentration

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21
Q

Facilitated diffusion

A

Used by small polar molecules that need assistance to pass through the membrane (making them polar mlcs)

High to low; down concentration gradient

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22
Q

What structures are needed for facilitated diffusion? Why do we need them?

A

Carrier proteins/transport proteins

Molecules passing through are polar and do not mix with the hydrophobic layer like nonpolar substances

23
Q

Any energy required for facilitated diffusion?

A

Nope, all flow down the concentration gradient

24
Q

How do carrier proteins actually move polar substances down the gradient?

A

Substances of high conc. bind to the protein, changing that protein’s shape and therefore its function, which is to now transport the molecule into the cell

25
Q

True or False:

Carrier proteins can carry any polar molecule into the cell.

A

False:

Carrier proteins can only transport one specific type of molecule due to specific protein conformation, making transport a highly specific process

26
Q

True or False:

The number of carrier proteins in the cell membrane limits the rate of diffusion by facilitated diffusion (transport maximum)

A

True; you can have oodles of molecules and substances that can pass the membrane, but there are only so many carrier proteins in the membrane. This limits how quickly substances can pass through.

27
Q

Active Transport

A

Movement of molecules across the membrane that requires energy via ATP or an ion gradient

28
Q

What does the flow of substances look like in active transport?

A

With active transport, the cell can move substances from where the substance has a low concentration to an area where the substance has a high concentration

29
Q

Do we still need transport proteins for active transport?

A

YES!

30
Q

Active transport allows the cell to concentrate certain ions either inside or outside of the cell. Why is this so important?

A

It’s important for maintaining the normal resting membrane potential

We see this commonly and Na/K pumps where active transport is used to maintain normal concentration gradients of sodium and potassium in an outside of the cell

31
Q

What are the concentrations of sodium and potassium in a cell?

A

Outside cell = more Na

Inside cell = more K

32
Q

Osmosis

A

The movement of water across the plasma membrane

33
Q

What proteins are involved in osmosis?

A

Aquaporins (protein channels)

34
Q

Is energy required for osmosis? Why or why not?

A

Nope because water will diffuse from the side of the membrane with higher water concentration to the side with lower water concentration

35
Q

How are substances moved into and out of the cell if they are much larger molecules?

A

Via vesicle formation

36
Q

What is the point of using vesicles?

A

It protects the cell and prevents it from damage/interruption.

The vesicles are formed by the plasma membrane, therefore the vesicles ARE the plasma membrane.

37
Q

Endocytosis

A

The process of substances being brought into a cell via vesicles

pinocytosis and phagocytosis

38
Q

Pinocytosis

A

When the cell takes in extracellular fluid and the molecules in that fluid //”cellular drinking”

Occurs in most cells

39
Q

What substances are taken in by the vesicles in pinocytosis?

A

Fat droplets or polypeptides

40
Q

Phagocytosis

A

“cell eating”

Used to take in very large substances such as cell fragments or microbes (ex: WBC like neutrophils or macrophages)

41
Q

Exocytosis

A

Moves vesicles out of the cell

Also called cell secretion

42
Q

The coordination between cells that allows for growth, cell division, and the functions of various tissues and organs systems is accomplished by what three ways?

A
  • Gap junctions
  • Direct cell to cell contact
  • Secretion of chemical mediators that influence distant cells
43
Q

Gap junctions

A

Direct connection of cytoplasm of adjacent cells that allows direct passage of small molecules and ions between cells

44
Q

What do gap junctions allow for a group of cells?

A

It allows them to act in unison

ex: used by cardiac muscle cells and some smooth muscle in the G.I. tract to coordinate contractions

45
Q

How do cells have direct contact with each other?

A

Cells use glycoproteins are glycolipids on their membranes to identify cells

We see this a lot in our immune system (ex: MHC cells, B-lymphocytes etc…)

46
Q

How do cells influence each other from great distances?

A

They secrete chemicals

47
Q

What is synaptic signaling?

A

When a neuron secretes a neurotransmitter diffuses across the synaptic cleft and ask on a post synaptic receptor to relay a message

48
Q

Where do we find synaptic signaling in our body cells?

A

Only in the nervous system

49
Q

Paracrine signaling

A

When cells secrete chemicals that only affect LOCAL cells before the chemical signals are destroyed

50
Q

Can you give an example of paracrine signaling?

A

Growth factors. They promote wound healing without affecting the entire organism. Only local cells grow to repair the wound.

51
Q

Endocrine signaling

A

When cells secrete hormones that travel throughout the bloodstream influencing only those cells which have the appropriate receptor for that hormone

52
Q

Autocrine signaling

A

When cells respond to the molecules they themselves secrete

53
Q

Well functioning in the autocrine signaling pathway can be involved with what type of disease?

A

Cancers

Pathophysiology (3 decks)

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