Practice Quest
Biology 12
Name: ______________
Date: _______________
Block: ______
Cells: Learning Goals 3-5
Learning Goal #5: Explain the relationship between cell size & surface area to volume ratio.
Your mission: a) Use the visual prompts below to explain limitations to cell size & which
types of cells are likely to be the most efficient.
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Cells are very small (usually less than 1 mm across) due to the SA:V ratio
As cell size increases the proportion of surface area available for the
diffusion of nutrients, wastes etc decreases dramatically in comparison
to cell’s larger volume. Ex. SA=6 V=1 =high ratio vs the large cell SA=24
V= 8 , larger cell ratio is lower 3:1 ratio, bigger cell is NOT as efficient
To function efficiently the cell must keep a high surface area compared
to a relatively low volume
Small cells have more surface are available for exchange compared to
the volume (distance) the materials need to travel
As cells increase in size, they may fold, flatten or lengthen to achieve
more surface area compared to volume
A larger cell can be efficient if it is somehow able to maintain a high
surface area compared to volume ratio
The 8 small cells are more efficient than 1 large cell
The larger cell C with microvilli on it’s surface is more efficient than cell A
which has less surface area because no microvilli (no folding)
Application: small intestine has villi to increase SA for nutrient absorption
Protozoan B can stay largehigh surface area made by it’s folded shape
Beginning
Developing
Accomplished
Exemplary
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Difficulty demonstrating
a basic understanding of
concepts.
Needs support to explain
& show knowledge using
key terms, images&
examples.
Struggles to relate &
apply knowledge to
other concepts
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
Demonstrates a basic
understanding of
concepts.
Needs to improve use
and connection of key
terms, images and
examples.
Partially relates and
applies knowledge to
other concepts
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
Demonstrates a solid
understanding of
concepts.
Able to connect some
key terms, images and
examples.
Moderately extends
knowledge through
connections &
applications to other
contexts.
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
Demonstrates a
complete and deep
understanding of
concepts.
Can connect key terms,
images & examples.
Thoroughly extends,
relates and applies
knowledge to a variety of
contexts & concepts
b) A biologist determined the surface area and volume of four cells:
Two flat cells with the same thickness and two spherical cells. Which
of the following four cells would have the greatest surface area to
volume ratio and why? Explain your answer.
i) A large, flat cell with a volume of 10 microlitres.
ii) A small, spherical cell with a volume of 5 microlitres.
iii) The small, flat cell with a volume of 5 microlitres.
iv) The large, spherical cell with a volume of 10 microlitres.
ANSWER: (iii) The small flat cell with a volume of 5 microlitres
REASONING:
The less volume a cell has, the less distance materials need to diffuse to enter and exit the cell.
This helps increase the cell’s efficiency at obtaining nutrients and excreting wastes.
Therefore, the options are either a small spherical cell with Volume of 5microlitres or a small flat
cell with the same volume
Flattening is one way that cells can increase their surface area compared to volume. A long flat
cell has more surface area available compared to it’s volume than a spherical cell.
The more surface area available compared to volume = a higher SA: V Ratio
Beginning
Developing
Accomplished
Exemplary






Difficulty demonstrating
a basic understanding of
concepts.
Needs support to explain
& show knowledge using
key terms, images&
examples.
Struggles to relate &
apply knowledge to
other concepts


Demonstrates a basic
understanding of
concepts.
Needs to improve use
and connection of key
terms, images and
examples.
Partially relates and
applies knowledge to
other concepts


Demonstrates a solid
understanding of
concepts.
Able to connect some
key terms, images and
examples.
Moderately extends
knowledge through
connections &
applications to other
contexts.


Demonstrates a
complete and deep
understanding of
concepts.
Can connect key terms,
images & examples.
Thoroughly extends,
relates and applies
knowledge to a variety of
contexts & concepts
Learning Goal #4: Describe cell structures, their functions & inter-relationships
Your mission: a) Describe how structures above: W, X, Y and Z work together.
STEP 1: Identify organelles
W: Endoplasmic Reticulum covered in Ribosomes X- Golgi Body with vesicles surrounding it
Y: Vesicles
Z- Cell (plasma membrane)
STEP 2: Clarify Functions & Structures of each organelle
W: system of membranous canals, used as a transport system for proteins. Rough ER has
ribosomes and ribosomes are like construction workers that assemble proteins based on the
genetic code
X: Golgi Body “PMS” : Packages, modifies and Sorts proteins. Also made up of membranes
& usually found near ER
Y: membranous sacs that transport materials around cell and to outside
Z: Cell membrane- entry & exit, controls what leaves/enters cell
STEP 3: Make connections & describe relationships
All of these structures are involved in making and secreting (transporting) proteins.
All of them are made up of membranes, and without one proteins could not be made or
delivered & the cell could not function properly.
b) How are the organelles shown in the electron micrographs above both similar and
different? How are they related?
STEP 1: Identify organelles
Mitochondria & Chloroplast
STEP 2: Clarify Functions & Structures of each organelle
Mitochondria- carries out cellular respiration to make “ATP” (the energy currency of the cell)
C6H12O6
+
6O2
 6CO2 + 6H2O + ATP
Glucose (carb) + oxygen  carbon dioxide + water + energy
System of folded membranes, double membraned organelle
Chloroplast- make food energy for plant cells FROM sun energy photosynthesis
Sun energy + 6CO2 + 6H2O  C6H12O6 + 6O2
Thermal energy + carbon dioxide + water  food energy + Oxygen
Double membraned organelle, made up of stacks (thylakoids) & grana
STEP 3: Make connections & describe relationship
Similarities- both double membranes & found in eukaryotic cells
- Both make a form of energy
Differences- chloroplast found only in plant cells  make food energy
- Chloroplast preforms photsynthesis vs mitochondria = cellular respiration
- -Mitochondria produces chemical energy
Related- Both are energy producers, yet also both require source of energy to function, a
plant cell requires both of these organelles to survive
STEP 4: EXTEND & APPLY KNOWLEDGE
Mitochondria & choloroplasts are similar to bacteria in size and structure. Their similar
double membrane structure supports the endosymbiont hypothesis that the outer
membrane may’ve come from being engulfed by an initial prokaryote.