Download Cell Biology FR Review

Cell Biology
Sample Free Response Questions
The following data were collected by
observing subcellular structures of three
different types of eukaryotic cells.
RELATIVE AMOUNTS OF ORGANELLES IN THREE CELL TYPES
Based on an analysis of the data, identify a likely primary
function of each cell type and explain how the data support
the identification. (3)
Cell Type
Smooth ER
Rough ER
Mitochondria
Cilia
Golgi Bodies
X
Small amount
Small amount
Large number
Present
Small amount
Y
Large amount
Large amount
Moderate number
Absent
Large amount
Z
Absent
Absent
Absent
Absent
Absent
This was a 3 point question on last
year’s exam…
Cell
Type
X
Identify function
• Locomotion •
Movement / surface
transport
• Secretion / exocytosis
• Protein synthesis
Y
•
•
Lipid/hormone
synthesis
Detoxification
Explain how data support
identification (1 point
each correct pair).
NOTE: No points for identification
without explanation.
Has cilia for movement and large
amounts of mitochondria to provide
energy for locomotion of cell itself
AND
(ciliated protist) or movement of
particles (mucus /oocyte) along cell
surface
AND
Has large amounts of rough ER and Golgi
to produce and package proteins
AND
Has large amounts of smooth ER to
produce lipids / hormones
Cell Z
Oxygen transport in
animal cells
AND
•
Water transport in
plant cells
• Epidermal cells (stratum
AND
corneum, cork, nails)
•
Ground tissue
(schlerenchyma)
AND
•
Vascular tissue
(xylem)
• Maximizes volume /
AND
space available
(hemoglobin, oxygen)
• Is a dead cell/is
AND
undergoing apoptosis
•
• Transport
OR
• Protection
OR
• Support
OR
• Storage
OR
• No function
OR
Does not
require
these
organelles
The membranes of the rough endoplasmic
reticulum have a very large surface area.
In one or two sentences, describe how a large
surface area aids the activities of the structure.
(2)
• Large amounts of surface area provide ample
areas for membrane bound enzymes to carry
out catalytic functions.
• These enzymes can modify and package
proteins for export.
Glycoproteins produced in the rough
endoplasmic reticulum may ultimately
be exported from the cell.
• In two or three sentences, describe the pathway of the
glycoprotein from the ER to the outside of the cell. (3)
• Glycoproteins are placed in vesicles, which are actively
transported to the Golgi apparatus for further
processing.
• In the Golgi, the glycoproteins are readied for leaving
the cell, then transported to the cell membrane by
vesicles which bud off the trans side of the Golgi body.
• The vesicles fuse with cell membrane, releasing the
glycoprotein into the intercellular matrix.
Living cells are highly organized and regulated.
Describe the structure of the plasma membrane.
• Plasma membranes are composed of a lipid
bilayer. Phospholipids are amphipathic; the
phosphate head faces the interior and exterior
of the cell, and the non-polar tail forms a
hydrophobic barrier that keeps out ions and
large polar molecules.
Explain how the plasma membrane
contributes to the regulation of the cell.
• Membrane proteins allow for large polar
molecules and ions to enter the cell via
specific channels.
• Non-polar molecules are free to diffuse into
the cell.
• Pump proteins are able to “grab” substances
using active transport (ATP) to pump
substances in or out of the cell, as needed.
What evidence supports the theory
that chloroplasts and mitochondria are
evolved from prokaryotic cells?
• Chloroplasts and mitochondria have their own
circular pieces of DNA, like prokaryotes.
• Their ribosomes, which are produced by the
organelles themselves, are similar to
prokaryotes and different from the rest of the
ribosomes in the cell.
• Chloroplasts and mitochondria divide by
binary fission, like prokaryotes.
The idea of surface area is an important
concept in biology.
• Explain how surface area plays a critical role in
the digestive system.
• Large amounts of surface area allow for
maximum nutrient absorption in the stomach
and small intestine.
In 1941, Daveson and Danielli proposed a
trilaminar structure of the cell membrane. The
model consisted of a layer of lipid with a layer
of protein on either side.
Describe the current model for the cell membrane.
The fluid mosaic model consists of a lipid bilayer with proteins embedded throughout.
Polysaccharides (glycogen in animals) are often attached to phospholipids and proteins,
and have regulatory functions, acting as receptors for incoming messages and recognition
markers for immune cells.
Membrane proteins can also be enzymes, portals for entry of molecules that do not pass
easily, and pumps that can import or export substances.
Describe and discuss THREE differences
between prokaryotic and eukaryotic cells.
• Eukaryotes contain organelles, which perform
specialized functions within cells. Prokaryotes do
not have organelles.
• Eukaryotes have chromosomes contained within
a nuclear membrane. Prokaryotes have a single
circular chromosome that is not bound within a
membrane.
• Eukaryotic cells are 10-100 times larger than
prokaryotic cells, grow more slowly, and have a
lower surface area/volume ratio. Eukaryotes use
oxygen for respiration, which prokaryotes do not.
Identify the cell organelle shown in the
micrograph below.
• Mitochondrion
Identify the structure labeled A and
explain how it is adapted for the organelle
to function efficiently.
• Cristae (inner membrane) provide additional
surface area for the enzymatic reactions of
respiration.