Ch 4 Test Yourself Flashcards
List three fluid compartments in the body
Intracellular, interstitial, intravascular
What is an electrolyte?
A charged particle (an anion or a cation) capable of conducting an electric current in solution
Give specific examples of both cation and anions
Cations:
* Potassium (K+)
* Magnesium (Mg2+)
* Calcium (Ca2+)
* Sodium (Na+)
Anions:
* Sulfate (SO42−)
* Hydrogen phosphate (HPO4 2−)
* Chloride (Cl−)
* Bicarbonate (HCO3−)
Which electrolytes are normally more concentrated outside the cell and which ones are more concentrated inside the cell?
Potassium is more concentrated inside the cell, sodium is more concentrated outside the cell
What is the relationship between solutes and osmolality?
Osmolality is a measurement of the concentration of solute in fluid; as the concentration of solute increases, osmolality also increases
Give specific examples of solutes in the body
Soluble proteins, phospholipids, cholesterol, triglycerides, sulfate, hydrogen phosphate, chloride, bicarbonate, magnesium, calcium, potassium, sodium
Why do changes in osmolality cause fluid to move from one compartment to another?
Water moves freely between fluid compartments based on changes in osmolality; fluid moves toward the compartment with the highest concentration of solutes
Give two examples of conditions that result from fluid shifts
Pulmonary edema, cutaneous edema
How do changes in the osmolality of body fluids affect an animal’s desire to drink?
An increase in osmolality stimulates the desire to drink and the release of antidiuretic hormone (ADH)
What is diffusion? Is it an active or a passive membrane process?
Diffusion is the passive movement of solute down a concentration gradient
What molecules are more likely to diffuse into a cell? What three principles are involved?
Molecules: Very small molecules (e.g., water), lipid-soluble molecules (e.g., alcohol, steroids), dissolved gases (e.g., O2, CO2)
Principles:
* Molecular size
* Lipid solubility
* Molecular charge
How is facilitated diffusion different from simple diffusion?
Facilitated diffusion requires the assistance of an integral protein or carrier protein; the number of available carrier proteins limits the rate of facilitated diffusion
What effect does a hypotonic solution have on a cell?
Water flows into the cell causing it to swell and possibly burst
What is the relationship between hydrostatic pressure and filtration?
Filtration is based on a pressure gradient; liquids are pushed through a membrane if the pressure on one side is greater than the other
What is another name for hydrostatic pressure in the body?
Blood pressure
What defines a passive membrane process?
A passive membrane process is one that does not require energy (ATP)
When is a membrane process considered active?
When the process requires energy
How do electrolytes enter the cell?
Via active transport
What is the difference between a symport and an antiport system?
Symport moves substances in the same direction; antiport moves substances in opposite directions
Describe how sodium and potassium enter and exit the cell
Potassium tends to diffuse out, sodium diffuses in; the cell must actively pump potassium in and sodium out
Describe the three types of endocytosis
Phagocytosis (solid material engulfing), pinocytosis (liquid engulfing), receptor-mediated endocytosis (specific ligands engulfing)
What is the difference between excretion and secretion?
Excretion is waste removal; secretion is movement of manufactured molecules; both are examples of exocytosis
What are the principal ions involved in maintaining a cell’s resting membrane potential?
Sodium and potassium
Is there normally a higher concentration of sodium inside or outside the cell?
Outside the cell
Where is there a higher concentration of potassium?
Inside the cell
What are the two major periods that comprise the life cycle of the cell?
Interphase and mitotic phase
Is interphase a time when the cell is resting? Why or why not?
No, interphase is a period of intense metabolic activity
What are the four stages of the mitotic phase?
Prophase, metaphase, anaphase, telophase
What happens in prophase?
Chromatin coils into chromosomes, cytoplasm becomes viscous, and a mitotic spindle forms
What happens in metaphase?
Chromosomes line up at the equator of the spindle, forming the metaphase plate
What happens in anaphase?
Centromeres split, chromatids are pulled apart, and the cell elongates
What happens in telophase?
Chromosomes unwind, nuclear envelopes form, and cytokinesis begins
What two major molecular components make up chromatin?
DNA and histone proteins
Why is it important for chromatin to supercoil and form discrete chromosomes before cell division?
To enable equitable division of genetic material without tangling or breaking
Why is protein and enzyme synthesis more likely to occur during interphase?
Chromosomes unwind, allowing access to DNA for transcription
What three factors play a role in the control of cell division?
Contact inhibition, growth-inhibiting substances, checkpoints during cell division
What is the genetic basis of cellular differentiation?
The position of genes in chromosomes determines gene accessibility for transcription
Of the thousands of different proteins that a cell could make, how many does it actually produce?
A few hundred kinds due to different cell functions
Where does protein synthesis begin?
In the nucleus
What is a nucleotide and how is it structured?
A nucleotide consists of a sugar, phosphate group, and nitrogenous base
Compare and contrast the structures of DNA and RNA
DNA has thymine; RNA has uracil; DNA is double-stranded; RNA is single-stranded
What are the nucleotides found in DNA?
Adenine (A), cytosine (C), guanine (G), thymine (T)
What are the nucleotides found in RNA?
Adenine (A), cytosine (C), guanine (G), uracil (U)
What is the term for mRNA formation?
Transcription
What are codons and what role do they play in transcription?
A codon is a set of three nucleotides in mRNA that specifies an amino acid or signals the end of synthesis
Can you describe the events that occur in translation?
Translation is the process of making protein from mRNA with the aid of ribosomes in the cytoplasm
What is the process of messenger RNA (mRNA) formation called?
Transcription
Transcription occurs in the nucleus.
What is a codon?
A set of three adjacent nucleotides in an mRNA molecule
Codons specify the incorporation of an amino acid or signal the end of peptide synthesis.
What role do codons play in transcription?
They specify the incorporation of an amino acid into a peptide or signal the end of peptide synthesis.
What is the process of making protein from mRNA called?
Translation
Translation occurs in the cytoplasm with the aid of ribosomes.
Where does translation occur in the cell?
In the cytoplasm
Ribosomes facilitate the translation process.
What do ribosomes do during translation?
They attach to mRNA and read the genetic sequence.
What is the function of transfer RNA (tRNA) in translation?
To bond to mRNA and bring amino acids for protein synthesis.
Fill in the blank: The ‘reading’ process in translation involves the bonding of a specific _______ on the tRNA to a complimentary codon on the mRNA.
anticodon
What forms on the ribosome during translation?
A polypeptide chain
This chain forms as amino acids bond together.
What happens to the polypeptide chain once it reaches its required length?
It disconnects from the ribosomal docking station.
When does DNA replication occur in the cell cycle?
During the synthetic (S) phase of interphase.
