Chapter 4, Cell Physiology Flashcards

1
Q

Fluid compartments in the body include

A

intracellular
Interstitial - surrounding cells, and
intravascular -found in lymphatic and blood vessels)

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2
Q

What is an electrolyte

A

An electrolyte is a charged particle (an anion or a cation) capable of conducting an electric current in solution.

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3
Q

Give examples of cations found in the body

A

Cations are positively charged and include potassium (K+), magnesium (Mg2+), calcium (Ca2+), and sodium (Na+).

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4
Q

Give specific examples of solutes in the body

A

Large molecules such as soluble proteins, phospholipids, cholesterol, and triglycerides
Smaller electrolytes such as sulfate, hydrogen phosphate, chloride, bicarbonate, magnesium, calcium, potassium, and sodium.

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5
Q

What is the relationship between solutes and osmolaty

A

Osmolality is a measurement of the concentration of solute in fluid. As the concentration of solute increases (or decreases), so too does the osmolality. In other words, fluids that have a high concentration of solutes have a high osmolality.

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6
Q

Why do changes in osmolaty cause fluids to move from one compartment to another

A

Normally, osmolarity in the intracellular fluid and extracellular fluid is equal. If either side ever has a few more solutes, than water will flow in that direction to lower the concentration slightly and maintain the balance. This process is called osmosis.

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7
Q

Give 2 examples of conditions that result in fluid shifts

A

Pulmonary edema and cutaneous edema

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8
Q

How do changes in osmolaty of body fluids affect an animals thirst and it’s ability to concentrate or dilute it’s urines.

A

A hormonal feedback loop helps maintain the osmolality of body fluids within a very narrow range of normal.

An increase in the osmolality of blood, for example, stimulates the desire to drink and the release of antidiuretic hormone (ADH). ADH then stimulates the kidney to resorb water from protourine resulting in the concentration of urine.

The opposite happens if the osmolality of blood becomes too low. The release of ADH in the brain is repressed and urine becomes concentrated via active removal of water from protourine in the kidney.

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9
Q

What is diffusion? Is it active or passive?

A

Diffusion is the passive movement of solute down a concentration gradient. (Greater to lesser until equilibrium).

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10
Q

What molecules are more likely to diffuse into a cell?

A

Small molecules, lipid soluble and charged molecules (through channel proteins).

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11
Q

How is facilitated diffusion different from simple diffusion? What is the limiting factor in the rate of facilitated diffusion

A

Facilitated diffusion requires the assistance of an integral protein or carrier protein located in the bilayer. The number of available carrier proteins limits the rate of facilitated diffusion.

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12
Q

What effect does a hyportonic solution have on a cell? What passive membrane process causes this effect?

A

If the extracellular fluid is hypotonic, the inside of the cell contains a higher concentration of solutes, so water would flow by osmosis into the cell and cause it to swell and possibly burst.

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13
Q

What is the relationship between hydrostatic pressure and filtration

A

Filtration is based on a pressure gradient. Liquids may be pushed through a membrane if the pressure on one side of the membrane is greater than that on the other side. The force that pushes a liquid is called hydrostatic pressure.

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14
Q

What is another name for hydrostatic pressure in the body

A

Blood pressure

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15
Q

What defines passive membrane process

A

A passive membrane process is one that does not require energy (ATP).

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16
Q

When is a membrane process considered active

A

The movement of molecules and substances across the cell membrane is considered active when the process requires ATP.

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17
Q

How do electrolytes enter the cell

A

Electrolytes enter cells via active transport (without the assistance of a concentration gradient).

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18
Q

What is the difference between a symport and an antiport system

A

Both symport and antiport move more than one substance at a time.

Symport- If all the substances are moved in the same direction, the system is called a symport system.

Antiport- when some substances are moved in one direction and others moved in the opposite direction, the system is called an antiport system.

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19
Q

Describe how potassium and sodium enter and leave the cell

A

Because of the concentration gradients of sodium (Na+) and potassium (K+), potassium tends to diffuse out of the cell and sodium diffuses in. To maintain appropriate levels of intracellular potassium and extracellular sodium, the cell must pump potassium into the cell and pump out sodium. The rate of transport depends on the concentration of sodium ions in the cell.

Because diffusion is ongoing, the active transport system must work continuously. ATP is provided by cellular respiration and, with the assistance of the enzyme ATPase, is broken down for use as energy on the inner surface of the cell membrane. The pump can cycle several times using just one molecule of ATP, so that for every molecule of ATP, two potassium ions are moved intracellularly and three sodium ions are moved extracellularly.

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20
Q

What is Endocytosis.

A

Endocytosis transports large particles or liquids into the cell by engulfing them. An example is neutrophils (White blood cells)

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21
Q

What is excretion? Secretion? They are examples of what?

A

Excretion is the movement of waste products from the intracellular to the extracellular environment, and secretion is the movement of manufactured molecules from the intracellular to the extracellular environment. Both are examples of exocytosis.

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22
Q

What are the principle electrolytes (ions) involved in maintaining a cells resting membrane potential

A

Sodium and Potassium

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23
Q

Is there normally a higher concentration of Sodium inside or outside the cell? What about Potassium

A

Sodium is 10 to 20 times higher outside the cell than it is inside. Potassium is 10 to 20 times higher inside the cell than outside.

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24
Q

What are the two major phases of a cell’s life

A

Interphase, when the cell is growing, maturing, and differentiating; and mitotic phase, when the cell is actively dividing.

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25
Q

Is the cell resting during interphase? Why or why not

A

No. Before each cell can divide, a perfect copy of the DNA must be created to pass on to the daughter cells In addition, all of the enzymes and other proteins needed to drive cell division must be created during interphase.

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26
Q

Describe prophase

A

Invisible chromatin- turns into two identical chromatids linked in middle by centromere
Spindle apparatus forms with centriole’s astal fibers
Nuclear envelope disintegrates

P- Chromatid Pops up, Centrioles Pushed apart

Less important-
Chromatin visible with light microscopy.
Cytoplasm becomes more viscous as microtubules from the cytoskeleton are disassembled and the cell becomes round.
Microtubules lengthen, they push the centrioles farther and farther apart.
Mitotic spindle is formed.
Because transcription and protein synthesis cannot occur while the DNA is tightly coiled, the appearance of chromosomes marks the cessation of normal synthetic processes. Prophase is thought to conclude with the disintegration of the nuclear envelope.

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27
Q

Describe Anaphase

A

The centromeres of the chromosomes split apart and each chromatid becomes its own chromosome as they move away from each other

Anaphase - Apart and Away

Less important -The
Spindle fiber separates & each spindle segment shortens
Chromosomes take on a V shape as they are dragged at their midpoint toward the centrioles at opposite ends of the cell.
The cell becomes elongated, and the cytoplasm begins to constrict along the plane of the metaphase plate.
Shortest phase

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28
Q

Describe Metaphase

A

Chromosomes line up randomly in the exact center of the spindle, known as the equator.

Metaphase- middle

Less important
Evenly spread chromosomes form what is called the metaphase plate midway between the poles of the cell.
The centromere of each chromosome is attached to a single spindle fiber. (In meiosis there are two successive divisions, ultimately producing four daughter cells. In mitosis, there is only one division and it produces two daughter cells.)

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29
Q

Describe telophase

A

Two new nuclei form
Chromosomes reach the poles unravel, elongate and become threadlike (chromatin)

T- Two and threadlike

Less important
Begins when chromosomal movement stops.
A nuclear envelope appears around each new set of chromosomes, and nucleoli appear in each nucleus.
Microtubules that made up the spindle disassemble,
A ring of peripheral microfilaments begins to squeeze the cell into two parts.

30
Q

Why is it important for chromatin to coil and form discrete chromosomes before cell division

A

DNA is a very long, cumbersome, and delicate molecule. The formation of duplicate, supercoiled chromosomes enables the cell to divide its genetic material without tangling or breaking the long, delicate chains of genetic code.

31
Q

What 3 factors play a role in the control of cell division

A
  1. Normal cells stop dividing when they come into contact with surrounding cells. This phenomenon is called contact inhibition.
  2. Growth-inhibiting substances may be released from cells when their numbers reach a certain point.
  3. A number of checkpoints are reached during cell division when the cell reassesses the division process. These checkpoints occur during the G1 and G2 phases of interphase.
32
Q

What is the genetic basis of cellular differentiation

A

The position of genes in chromosomes determines the genetic basis of cellular differentiation. Some genes may be located on a region of the chromosome that is available for transcription, whereas other genes may be located inside the molecule and cannot be reached by transcription molecules. Differentiation involves the temporary or permanent inhibition of genes that may be active in other cells.

Reference histones from chapter 3 for a better answer

33
Q

Of the thousands of different proteins a cell can make, how many does it actually produce? Why

A

Of approximately 100,000 proteins that a cell could make, it makes only a few hundred because cells have different functions. The number of proteins made depends on the function of the cell.

34
Q

Compare and contrast DNA and RNA

A

DNA and RNA are both made of a phosphate group, a sugar and a nitrogenous base. In DNA the sugar is deoxyribose, and in RNA the sugar is ribose.

In DNA these bases are weakly bonded to nitrogenous bases on an opposing strand. In this way, DNA forms a double-stranded molecule, in which the vertical poles are composed of alternating sugar and phosphate groups and the horizontal rungs are paired nitrogenous bases.

DNA’s molecular structure is therefore called the double helix. RNA, however, is a single-stranded molecule that has no opposing strand. The single strand of RNA is similar in structure to each of the strands found in DNA.

35
Q

What nucleotides are found in DNA? In RNA?

A

The nucleotides found in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T). The nucleotides found in RNA are adenine (A), cytosine (C), guanine (G), and uracil (U).

36
Q

What is the term for mRNA formation

A

Messenger RNA (mRNA) formation is known as transcription, which occurs in the nucleus.

37
Q

What are codons and what role do they play in transcription

A

A codon is a set of three adjacent nucleotides in an mRNA molecule that specifies the incorporation of an amino acid into a peptide or polypeptide chain or that signals the end of peptide synthesis.

38
Q

What occurs in translation (big picture)

A

Translation is the process of making protein and occurs in the cytoplasm with the aid of ribosomes. Protein synthesis can occur either in cytosol, using free-floating ribosomes, or on rough endoplasmic reticulum (rRER), using fixed ribosomes.

  • the steps of the process
    Binding
    Pairing
    Linking
    Elongation
    Coils
    Release
39
Q

When in the cell cycle does DNA replication occur

A

DNA replicates during the synthetic (S) phase of interphase

40
Q

Osmosis

A

Diffusion of water through semi-permeable membrane. (Tonicity - amount of solute (particles dissolved in a solution. Isotonic is balanced)

41
Q

Hypertonic

A

ECF is more concentrated than cytoplasm. Water shifts into ECF and cell shrinks

42
Q

S phase

A

DNA is replicated. New histones are formed and assembled into chromatin.

43
Q

G1 Phase

A

Cell is active. Organelles duplicate. Cell doubles in size. Cetrioles begin to replicate

44
Q

G2 Phase

A

Is very brief. Centrioles complete their replication. Enzymes and proteins necessary for cell replication are synthesized.

45
Q

Meisosis

A

Cell division process where we go from 1 mother cell to 4 daughter cells and each daughter cell has different DNA. ( Diploid to haploid (2n to 1n)) Creation of gametes- sperm and egg.

Unlike metaphase in mitosis, Meiosis 1 paired chromosomes move to the middle.

46
Q

Genetic mutations

A

Errors in DNA replication. Mutagens are anything that causes an error - viruses, radiation, chemicals, spontaneous mutation

47
Q

Fluid therapy

A

Used to maintain hydration
Used to treat ongoing fluid loss
Commonly used to maintain venous access during surgical procedures and in patients receiving IV meds
During emergencies used to increase osmotic pressure, improve urine output, correct acid/base imbalances, correct electrolyte imbalances

48
Q

Active Transport Types

A

Sodium/Potassium Pump
Endocytosis - WBC phagocytosis
Exocytosis - Neurotransmitter release

49
Q

List types of Passive Transport

A

Diffusion- Movement of O2 through membrane
Facilitated Diffusion - Movement of glucose into cell
Osmosis- Movement of water in and out
Filtration- needs hydrostatic pressure- Formation of kidney filtrate

50
Q

Mitosis

A

Cellular division of non-sex cells. Going from 1 mother cell to daughter cells. Daughter cells have same DNA as mother cells

51
Q

Give examples of anions found in the body

A

Anions are negatively charged and include sulfate (SO4(2)-), hydrogen phosphate (HPO4(2)-), chloride (Cl-), and bicarbonate (HCO3-).

52
Q

What 3 principles of diffusion

A
  1. Molecular size: Very small molecules, such as water (H2O), may pass through cellular membrane pores (approximately 0.8 nm in diameter), but larger molecules, such as glucose, cannot.
  2. Lipid solubility: Lipid-soluble molecules (e.g., alcohol and steroids) and dissolved gases (e.g., oxygen [O2] and carbon dioxide [CO2]) can pass through the lipid bilayer with ease, whereas other molecules may not.
  3. Molecular charge: Ions are small, but their charge prevents easy passage through the membrane pores. Specialized pores called channels selectively allow certain ions to pass through but not others.
53
Q

Describe the 3 types of endocytosis

A

The three types of endocytosis are phagocytosis (solid), pinocytosis (liquid), and receptor-mediated endocytosis.

54
Q

Cytokinesis

A

Occurs after telophase- the cell pinches itself in half, dividing the cytoplasm and forming two completely separate daughter cells.

55
Q

2nd stage of transcription

A

Elongation- RNA polymerase moves along the DNA strand and coordinates pairing of corresponding RNA to DNA. Linked by mRNA

Steps of transcriptions
Initiation
Elongation
Separation
Termination

56
Q

1st stage of transcription

A

Initiation- RNA polymerase binds to a DNA molecule and initiates separation of the DNA molecule. A specific section of DNA is exposed

Steps of transcriptions
Initiation
Elongation
Separation
Termination

57
Q

3rd stage of transcription

A

Separation - RNA polymerase reaches the end of the gene, and the newly formed mRNA molecule is released and travels to the cytoplasm

Steps of transcriptions
Initiation
Elongation
Separation
Termination

58
Q

4th stage of transcription

A

Termination- The separate strands of DNA in the nucleus form a double helix again

Steps of transcriptions
Initiation
Elongation
Separation
Termination

59
Q

1st stage translation

A

Binding- (In cytoplasm) A ribosome binds to the beginning of the mRNA strand

  • the steps of the process
    Binding
    Pairing
    Linking
    Elongation
    Coils
    Release
60
Q

2nd stage translation

A

Pairing - Transfer RNA moves in. The tRNA codon is paired with the appropriate mRNA codon

  • the steps of the process
    Binding
    Pairing
    Linking
    Elongation
    Coils
    Release
61
Q

3rd stage of translation

A

Linking- the amino acid carried by the tRNA is released and linked to the neighboring amino acid

  • the steps of the process
    Binding
    Pairing
    Linking
    Elongation
    Coils
    Release
62
Q

What are tetrads and why are they important

A

Tetrads are a group of two homologous chromosomes, which come together undergoing the crossover event. The tetrad occurs during the first phase of meiosis. It is the foursome of chromatids that forms when replicated homologous chromosomes align. It must be formed for crossing over to occur. Meiosis 2 then occurs which is like Mitosis.

63
Q

4th stage translation

A

Elongation - the ribosome continues to move along the mRNA molecule until all codons have been paired

  • the steps of the process
    Binding
    Pairing
    Linking
    Elongation
    Coils
    Release
64
Q

5th stage translation

A

Coils- The developing chain of amino acids lengths, coils, and folds into structural proteins

  • the steps of the process
    Binding
    Pairing
    Linking
    Elongation
    Coils
    Release
65
Q

6th stage translation

A

Release -When translation is complete the new protein is released and later modified. The mRNA, tRNA and ribosome can now make more proteins

  • the steps of the process
    Binding
    Pairing
    Linking
    Elongation
    Coils
    Release
66
Q

Describe Osmosis

A

Passive movement of water through a semipermeable membrane to a solution with a lower water concentration (opposite direction of diffusion, water is moving)

67
Q

Describe the process of active transport

A

Active transport requires ATP. It relies on a carrier protein with a specific binding site. A major example is the NaK pump

68
Q

Endocytosis

A

Large particles brought into cell by being engulfed. The cell involutes (goes in and surrounds). Phagocytosis means it engulfs a solid, pinocytosis means it engulfs a liquid

Extra- macrophage is found in mammals for swallowing debris/dead cells/etc

69
Q

Exocytosis

A

Cells export substances from intracellular environment.

70
Q

Describe the role of ions in a cells resting potential

A

A cell generally has a more negative charge inside the cell than outside . The principal ions responsible for establishing the resting membrane potential are those of chloride, potassium, and sodium.