Download Unit 4 ~ Learning Guide Name

BCLN BIOLOGY 12 – Rev July 2014
Unit 4 ~ Learning Guide
Name:
INSTRUCTIONS
Complete the following notes and questions as you work through the related lessons.
You are required to have this package completed BEFORE you write your unit test. Do
your best and ask questions about anything that you don't understand BEFORE you
write the unit test.
U4L1 NOTES: INTRODUCTION (web notes and video)
YOU SHOULD WATCH THE OSMOSIS LAB
VIDEO BEFORE PROCEEDING ANY FURTHER!
Cell Membrane Structure
•
•
Early Theory: Proteins were sandwiched between 2 layers of phospholipid
molecules.
Problem: Since the phospholipid tails are hydrophobic (hate water) this theory
did not explain how water can travel freely through membranes.
Fluid Mosaic Model:
• Accepted Theory: There is a double layer of phospholipids but the
•
Water travels through the pores formed by the proteins
YOU SHOULD WATCH THE FLUID MOSAIC MODEL VIDEO
BEFORE PROCEEDING ANY FURTHER!
•
The proteins have
accounts for their placement among the
,
which
.
Some of the proteins and phospholipids have carbohydrate chains attached
to them.
Protein + Carbohydrate chain =
Phospholipid + Carbohydrate chain =
Page 1 of 17
BCLN BIOLOGY 12 – Rev July 2014
These
carbohydrate
chains function
. A body will
as
cells with the wrong markers.
Example: Organ rejections in transplants
YOU SHOULD WATCH THE CELL MEMBRANE AND STRUCTURE
VIDEO BEFORE PROCEEDING ANY FURTHER!
Page 2 of 17
BCLN BIOLOGY 12 – Rev July 2014
U4L1 PRACTICE: INTRODUCTION
1. Describe the fluid mosaic model. (2 marks)
2. What prefix is used to indicate a protein or lipid that has a carbohydrate chain
attached? (1 mark)
3. Please label the following cell membrane diagram with as much detail as
possible. (5 marks)
Page 3 of 17
BCLN BIOLOGY 12 – Rev July 2014
U4L2 NOTES: CELL MEMBRANE FUNCTION (web notes and
video)
Following are some definitions you should understand:
•
•
•
Impermeable Permeable Semi-permeable -
.
.
.
**SELECTIVELY PERMEABLE** .
•
Certain smaller and certain large molecules can pass through.
Cell Membranes are selectively permeable (also called differentially
permeable).
YOU SHOULD WATCH THE MOVEMENT ACROSS THE CELL MEMBRANE
VIDEO BEFORE PROCEEDING ANY FURTHER!
Movement Across Membranes:
4 main ways:
1. DIFFUSION:
from an area of
high concentration to an area of low concentration until evenly distributed. No
membrane, carrier, or ATP required.
*A Solute is made up of solid particles or
molecules suspended in air or liquid.*
•
•
•
•
Diffusion Example: A foul odour in the corner of a room will spread out
until it is evenly distributed
Diffusion Example: Cream in coffee will diffuse until concentration are
balanced
Diffusion refers to the process by which molecules intermingle as a result
of their
of random motion. Consider two
containers of gas A and B separated by a partition. The molecules of both
gases are in constant motion and make numerous collisions with the
partition.
If the partition is removed as in the illustration, the bases will mix because
of the random velocities of their molecules. In time a
Page 4 of 17
BCLN BIOLOGY 12 – Rev July 2014
of A and B molecules will be
produced in the container.
2. OSMOSIS:
.
•
•
•
Pressure caused by the
between two different solutions is called
. Hydrostatic pressure offsets osmotic
pressure. (Gravity)
The solute cannot spread out because it is
the membrane. Therefore,
water moves across the membrane from [high water] to [low water].
Recall: square brackets represent the term "concentration" as in [high
salt] = high salt concentration
Water moves through the protein-lined pores of the cell membrane.
Hypertonic, Hypotonic and Isotonic Solutions
Hypertonic Solutions:
Hypotonic Solutions:
Isotonic Solutions:
Water will always move from a
solution to a
solution. There is no net movement of water
between
solutions.
Tonicity:
.
Page 5 of 17
BCLN BIOLOGY 12 – Rev July 2014
You should watch the OSMOSIS videos and animations and identify the
hypertonic and hypotonic solutions in the video before proceeding any further!
3. FACILITATED TRANSPORT: (
• Solutes
move
across
a
membrane
[
] to and area of [
the help of a carrier molecule (protein).
)
from
an
area
of
] with
.
•
Example of Solute: Glucose
Molecules
4. ACTIVE
needed
by
the
TRANSPORT:
cell such as
from the blood.
Solutes
move
glucose,
from
enter
an
through
area
of
across a membrane with the aid of
•
.
Example of Solute: Ions such as Na+
Since
the
gradient,
o
o
movement
is
against
is required.
the
concentration
Example:
is removed from the urine,
by active transport, into the blood. Since there is already a lot of glucose in
the blood, it is traveling
the concentration gradient.
Example:
. Found in nerve and muscle cells.
Same carrier, but changes shape to fit Na+ and K+.
Page 6 of 17
BCLN BIOLOGY 12 – Rev July 2014
Transport Across the Membrane Summary
There are always four points to consider when comparing the types of movement
across a membrane. Is a membrane, carrier, or energy in the form of ATP required, and
is transport with or against the concentration gradient.
Factors Affecting Diffusion
Surface Area Vs. Volume
Nutrients (
) enter a cell while wastes (carbon
dioxide and urea) exit a cell across the cell membrane.
The amount of cell membrane - =
•
Inside the cell, organelles use up nutrients and produce
The larger the cell, the more
.
.
The size of the cell (# of organelles) =
•
•
•
•
•
•
Small cells have a
SA:Volume ratio. They
supply the organelles
plenty of nutrients
remove wastes.
Large
cells
have
high
can
with
and
a
because volume increases
faster than surface area. If a
cell gets too big, wastes will
build up and nutrients will
run out.
Therefore, cells are limited in
size. Active cells must be
than less active cells. Active cells need
more
.
Cells reproduce by mitosis to become smaller
Some cell are able to get larger than they should be able to by producing
These folds allow the cell to gain more surface area without a large increase in
volume
Page 7 of 17
BCLN BIOLOGY 12 – Rev July 2014
Factors That Will Increase Diffusion
Movement of the medium •
Example: Stirring cream in coffee.
Endocytosis versus Exocytosis
Endocytosis - process in which large materials enter a cell
.
• Phagocytosis --"Cell eating" -very large pieces
•
Pinocytosis - A type of endocytosis in which molecules such a proteins are
taken in (liquid).
--"
" -smaller "larger" pieces
Exocytosis
• Exocytosis - A
process by which products or
wastes exit
.
YOU SHOULD WATCH THE FACILITATED TRANSPORT
VIDEO BEFORE PROCEEDING ANY FURTHER!
Page 8 of 17
a cell.
BCLN BIOLOGY 12 – Rev July 2014
U4L2 PRACTICE: CELL MEMBRANE FUNCTION
1. Please define the following terms and provide one example where it is involved in
transporting a substance in the human body:
a. diffusion (2 marks)
b. osmosis (2 marks)
c. facilitated transport (2 marks)
d. active transport (2 marks)
2. There are several ways to transport substances across the cell membrane.
Please complete the table below, indicating whether the form of transport
requires a membrane, carrier, energy in the form of ATP, and is with the
concentration gradient. (8 marks)
Type
Transport
of
Membrane
Required
( or )
Carrier
Required
( or )
Diffusion
Osmosis
Facilitated
Transport
Active
Transport
Page 9 of 17
Energy/ATP
Required
( or )
With
concentration
Gradient
( or )
BCLN BIOLOGY 12 – Rev July 2014
3. Which mode of transport is used to move the following molecules across the cell
membrane? (4 marks)
a. oxygen molecules
b. water
c. sodium ions
d. glucose
4. Why is the cell membrane important to the cell? (2 marks)
5. What factors influence the rate at which specific molecules diffuse across the cell
membrane? (3 marks)
6. Why does winter road salt cause damage to plants on the roadside? (1 mark)
7. Salting fish was a common practice. How did this practice prevent the fish from
rotting? (1 mark)
8. Compare and contrast
pinocytosis,and exocytosis.
the body. (4 marks)
endocytosis, including both phagocytosis and
Include an example of the use of each process in
PLEASE REMEMBER:
YOU MUST PERFORM AND SUBMIT THE OSMOSIS LAB BEFORE
THIS UNIT IS COMPLETE! REFER TO THE UNIT 4 DROP-DOWN
MENU TO ACCESS THE LAB GUIDE AND LAB.
~ END OF BIOLOGY 12 UNIT 4 LEARNING GUIDE ~
Page 10 of 17
BCLN BIOLOGY 12 – Rev July 2014
UNIT 4 ANSWER KEY
U4L1 PRACTICE: INTRODUCTION
1. Describe the fluid mosaic model. (2 marks)
= states that the cell membrane (aka the plasma membrane) is made up of a semifluid (dynamic and changing) phospholipid bilayer with a variety of proteins floating
within that bilayer
2. What prefix is used to indicate a protein or lipid that has a carbohydrate chain attached? (1 mark)
= glycol as in glycoprotein or glycolipid
3. Please label the following cell membrane diagram with as much detail as possible. (5 marks)
Page 11 of 17
BCLN BIOLOGY 12 – Rev July 2014
U4L2 PRACTICE: CELL MEMBRANE FUNCTION
4.
Please define the following terms and provide one example where it is involved in transporting a
substance in the human body:
a.
diffusion (2 marks) = the movement of particles from areas of higher concentration to areas
of lower concentrations until equilibrium is met
b. osmosis (2 marks) = the movement of water molecules from areas of lower concentration
(note lower concentration of solution actually means greater amounts of water) to areas of
higher concentrations (note higher concentration of solution actually means greater amounts
of water) across a semi-permeable membrane until equilibrium is met…instead of
concentration simply think of the movement of water from areas with greater/higher
amounts of water to areas of lesser/lower amounts of water
5.
c.
facilitated transport (2 marks) = any form of diffusion that requires the assistance of a
carrier or channel protein, the protein's assistance is generally required to either limit the
transported substance's interactions with the cell membrane (such as with negative ions
that would be repelled by or positive ions that would be attracted to the negative membrane
without the assistance ) or because the transported substance is simply too large to diffuse
directly across the membrane, process is energy-independent as it is diffusion and particles
are moving along their concentration gradient from high to low
d.
active transport (2 marks) = any form of transport that requires energy (typically supplied in
the form of ATP) such as when substances are moved against their concentration gradients
(from lower concentrations to higher concentrations) of moved within vesicles
There are several ways to transport substances across the cell membrane. Please complete the
table below, indicating whether the form of transport requires a membrane, carrier, energy in the form
of ATP, and is with the concentration gradient. (8 marks)
Type of
Transport
Diffusion
Membrane
Required
( or )

Carrier
Required
( or )

Energy/ATP
Required (
or )

With
concentration
Gradient
( or )

 (with respect to
Osmosis

Facilitated
Transport
Active
Transport



 (or channel)

Page 12 of 17

water moving from
areas of higher
water to areas of
lower water)




BCLN BIOLOGY 12 – Rev July 2014
6. Which mode of transport is used to move the following molecules across the cell
membrane? (4 marks)
a. oxygen molecules
_
b. water
_
c. sodium ions
d. glucose
_
4. W hy is the cell membrane important to the cell? (2 marks)
= defines the boundaries of the cell from the surrounding environment
= controls what enters and exits the cell
5. What factors influence the rate at which specific molecules diffuse across the cell
membrane? (3 marks)
Answer should include any 3 of the following:
= surface area…greater surface are = faster diffusion
= temperature…higher temperature = faster diffusion
= concentration gradient…greater gradient (the greater the difference between the
higher and lower concentration areas) = faster diffusion
= size of diffusing particle…smaller particle = faster diffusion
= diffusion medium…solid=slower, liquid = faster, gas = fastest
6. Why does winter road salt cause damage to plants on the roadside? (1 mark)
= the excess salt mixes with water in the environment and essentially places
the plant in a hypertonic solution that then causes water to exit the plant cell
thereby damaging the plant
7. Salting fish was a common practice. How did this practice prevent the fish from rotting?
(1 mark)
= the excess salt mixes with water in the environment and essentially places
any potential bacteria that could lead the fish to rot in a hypertonic solution
that draws the water from the bacteria causing it to die
8. Compare and contrast endocytosis, including both phagocytosis and pinocytosis, and
exocytosis.
Include an example of the use of each process in the body. (4 marks)
Page 13 of 17
BCLN BIOLOGY 12 – Rev July 2014
= endocytosis and exocytosis both active transport processes that use ATP and
vesicles to transport substances
= endocytosis specifically refers to the use of vesicles to actively
move substances into the cell and includes phagocytosis or "cell eating"
whereby larger particles are brought into the cell and pinocytosis or "cell
drinking" whereby fluids and smaller particles are brought into the cell; also
includes receptor-mediated
endocytosis which only occurs in response to a ligand of some sort
specifically
binding to a receptor to initiate the process of
endocytosis
= exocytosis specifically refers to the use of vesicles to actively
move substances out of the cell and includes constitutive exocytosis or secretion
whereby a substances is continually secreted from the cell and receptormediated or regulated exocytosis whereby a substance is only moved out of the
cell in response to some sort of ligand specifically binding to a receptor to
initiate the process of exocytosis
= phagocytosis…uptake of bacteria pathogens for destruction within the cell
= pinocytosis…uptake of nutrients by cells in the small intestine
= receptor-mediated endocytosis…iron and cholesterol uptake
= constitutive exocytosis…collagen and plasma membrane lipids
= regulated exocytosis…
Page 14 of 17