Anatomy & Physiology
LAB #2
The Cell- Structure & Function
Cell Physiology- Movement of a Substance Across the Cell Membrane
1. Define:
a) cell-the basic structural & functional biological unit of all living organisms.
-contains a nucleus and a variety of organelles enclosed by a limiting
membrane
b) organelle-are small specialized structures that perform specific metabolic
functions for the cell as a whole - the metabolic machinery of the cell
- each organelle has specific functions
c) cytosol-composes of water, solutes, suspended particles, lipid, droplets, and
glycogen granules
d) inclusions-non-functioning units within a cell
-chemical substances that may or may not be present depending on
specific cell type - usually store nutrients or cellular products- ie. fat
droplets in fat cells or pigments in hair cells
2. In relation to the cytoskeletonal filaments - define:
a) microfilaments-thinnest filaments - locomotion and division - provide support for microvilli and
help to increase surface area of the cell (increase absorption ie. small intestine)
b) intermediate filaments-several different proteins - anchor organelles
c) microtubules-large cylindrical structures - flagella, cilia (cilia move fluids over a cell’s
surface; flagella move a entire cell
3. Fill in table
Organelle
ribosomes
smooth endoplasmic
reticulum (SER)
rough ER
golgi complex
lysosomes
Function
-packages of ribosomal RNA & protein - free ribosomes are loose
in cytosol - membrane bound ribosomes are attached to
endoplasmic reticulum (RER)
-protein synthesis
-not attached to ribosomes - synthesizes fatty acids, steroids detoxifies harmful substances (alcohol) - stores and releases
calcium ions in muscle cells
-covered with attached ribosomes - synthesizes, processes &
packages proteins for export - free ribosomes synthesize
proteins for local use
-convex side faces ER & concave side faces cell membrane processes & packages proteins produced by rough ER
-formed in golgi complex - filled w/ digestive enzymes - pH of 5 -
peroxisomes (don’t
need to label on
diagram)
mitochondria
nucleus
digest foreign substances - autophagy (recycles worn out
organelles) - autolysis (self destruct of cells after death or in a
pathological process)
-smaller than lysosomes - part of normal metabolic breakdown of
amino acids and fatty acids - oxidizes them(removes hydrogen
atoms) -detoxifies harmful substances such as alcohol,
produces hydrogen peroxide- contains the enzyme catalase
which decomposes H2O2 (hydrogen peroxide-a toxic byproduct)
-generation of ATP - power house of cell - they self-replicate w/
the increase in need for ATP (adenosine triphosphate)
-contains genes, which control cellular structure and direct
cellular functions
-“control centre of the cell”
4. Using the organelles from the table in question 3 label the following diagram.
5. Define mitosis.
-a cell undergoes a nuclear division, and ensures that each new daughter nucleus has
the same number and kind of chromosomes as the original parent nucleus
Define the 4 stages of actual division:
a) Prophase:
-chromatin fibers condense into paired chromatids; nucleolus and nuclear
envelope disappear; each centrosome moves to an opposite pole of the cell
b) Metaphase:
-centromeres of chromatid pairs line up at metaphase plate
c) Anaphase:
-centromeres split; identical sets of chromosomes move to opposite poles of
cell (once separated the chromatids are termed chromosomes)
d) Telophase:
-nuclear envelopes and nucleoli reappear; chromosomes resume chromatin
form; mitotic spindle disappears
Cell Physiology, Movement of a Substance Across the Cell Membrane
1. Define the following terms as they relate to cell membrane transport:
solution-in a solution, it contains a substance called a solvent that dissolves another
substance called the solute-usually there is more solvent than solute in a solution ie.
your sweat is a dilute solution of water (the solvent) plus small amounts of salts (the
solutes)
solvent-ie. water- liquid that dissolves a solute
solutes-ie. salts - substance to be dissolved
intracellular fluid-the fluid within the cell (ICF)
ADD - extracellular fluid ECF- The fluid outside of the body cell
interstitial fluid -is the narrow spaces between cells of tissues filled with ECF
permeable -is a membrane that allows substances to pass through
selectively permeable -is a membrane that permits some substances to pass more
readily than others
passive transport processes -a substance moves down a concentration ( [ ] ) gradient
across a membrane using only its own kinetic energy (from high [ ] gradient to a low
[ ] gradient)
active transport processes -energy is used to drive the substance “uphill” against a [ ]
gradient
2.Define: diffusion: -passive transport process - movement of substance due to kinetic
energy-molecules move from an area of high [ ] to low [ ] - down the [ ] gradient
Which of the following are examples of diffusion?
a) a perfume bottle is opened and soon you can smell it in the whole room. Yes / No
b) a sugar cube is dropped in your coffee and becomes sweet without stirring. Yes / No
c) water moves through a garden hose when the faucet is turned on. Yes / No
d) a person blow air into a balloon. Yes / No
3. Define: osmosis: -the diffusion of a solvent (usually H2O)) through a selectively
permeable membrane from an area of high water [ ] to an area of lower water [ ] until
equilibrium is reached
osmotic pressure: - pressure to resist further diffusion of a solvent into a cell
Which of the following involves osmosis?
a) garden grass wilts after being exposed to dry fertilizer Yes / No
b) air molecules escape from a punctured tire Yes / No
c) Plant seeds soaked in water become larger. Yes / No
How does osmosis differ from diffusion?
-osmosis is the diffusion of a solvent (H2O) through a selectively permeable
membrane
Predict & explain what would happen to the hydration (fluid) status of an infant if (s)he
received concentrated formula rather than an appropriate diluted one.
-H2O is pulled from cells
-infant becomes dehydrated
4. Define: facilitated diffusion -diffusion in which a substance in not soluble by itself
and diffuses across a selectively permeable membrane with the help of a transporter
protein
How does facilitated diffusion differ from osmosis and diffusion?
- osmosis and diffusion do not need a transporter
5. How does active transport differ from osmosis, diffusion and facilitated diffusion?
-uses ATP - goes against the [ ] gradients from low [ ] to high [ ]
-whereas diffusion and facilitated diffusion go from high to low [ ] - high to low
pressure
6. Define the following terms relation to vesicular transport:
Endocytosis: - bringing something into cell -examples: phagocytosis &
pinocytosis
Phagocytosis: - cell eating by macrophages & WBC’s - worn out cells, whole
bacteria or viruses are engulfed & later digested
Pinocytosis: - cell drinking- most body cells can ingest membrane-surrounded
droplets of interstitial fluid
Exocytosis: - release something from the cell - digestive enzymes, hormones,
neurotransmitters or waste products - replace cell membrane lost
by endocytosis
7. Define the following terms as they relate to solutions:
isotonic - water [ ] the same inside & outside of cell results in no net movement
of water across cell membrane
hypotonic - higher [ ] of water outside of cell -causes the cell to swell
hypertonic - lower [ ] of water outside of cell causes crenation (shrinkage)
8. In the drawings below, a red blood cell (RBC) is in solutions of various strength (isotonic,
hypertonic & hypotonic). The diagrams on the left show the size of the RBC before it was put
into the solution.
a) Using your knowledge of osmosis, describe what (if anything) happened to the RBC.
b) state what type of solution the RBC is in (isotonic, hypertonic, or hypotonic).
RBC
Solution A
The RBC___shrinks__________________
This solution is__hypertonic____________
RBC
Solution B
The RBC____same___________________
This solution is__isotonic_______________
RBC
Solution C
The RBC___swells____________________
This solution is__hypotonic______________