Download CELLS: ANIMAL CELLS 13 FEBRUARY 2013 Key Concepts

CELLS: ANIMAL CELLS
13 FEBRUARY 2013
Lesson Description
In this lesson we will discuss the following:
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The Cell Theory
Terminology
Parts of a Microscope
The definition of a Cell
Examples of Cells
Type of Cells
Plant and Animal Cells
Parts of Animal Cells: Organelles
Key Concepts
The Cell Theory
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All living things are made up of cells and are either unicellular or multicellular.
Cells are the smallest working units of all living things that show the characteristics and
properties of life.
All cells come from preexisting cells through cell division.
How do living organisms compare in size:
Diagram adapted from Via Afrika Life Sciences Grade 10 Learners Book
Important Terms:
Cell
Cell membrane
Centriole
Centrosome
Chromatin network
Cytoplasm
Endoplasmic reticulum
Golgi body
Mitochondrion
Nucleus
Nucleolus
Nuclear membrane
Organelle
Phagocytic
Pseudopodia
Ribosomes
Vacuole
Parts of a Microscope:
Diagram adapted from Via Afrika Life Sciences Grade 10 Learners Book
Examples of Cells
Diagram of a Red blood cell
Diagram of a Nerve cell
Diagram of a Bacterial cell
Diagram of an Amoeba cell
Type of Cells
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Prokaryotic
Eukaryotic
Prokaryotic Cells
Diagram of a Bacterial Cell
Characteristics of Prokaryotic cells
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No true nucleus ,have stands of DNA or RNA
Do not have structures surrounded by membranes
Few internal structures
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One-celled organisms, e.g. Bacteria
Eukaryotic Cells
Diagram of a Plant Cell
Characteristics of Eukaryotic cells
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Have a true membrane bound nucleus
Have structures surrounded by membranes
Complex internal structures
Typical Animal and Plant Cells
Diagram showing the cross section of a typical animal cell
Diagram showing the cross section of a typical plant cell
Parts of Animal Cells
A typical animal cell consists of the following parts:
 A Cell membrane
 A Nucleus
 The Cytoplasm
 The various organelles
Cell Membrane
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Outer membrane of cell that controls movement in and out of the cell
Double layer
Diagram showing the structure of a cell membrane
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The fluid mosaic model describes the structure of the plasma membrane.
Different kinds of cell membrane models have been proposed, and one of the most useful is
the Fluid-mosaic model. In this model the membrane is seen as a bilayer of phospholipids
in which protein molecules are embedded.
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Channels/pores - A channel in the cell's plasma membrane. This channel is made up of
certain proteins whose function is to control the movement of food and water into the cell.
These channels are made up of certain proteins.
Nucleus
Diagram showing the structure on a nucleus
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The nucleus is the control center of the cell. It is the largest organelle in the cell and it
contains the DNA of the cell. The DNA of all cells is made up of chromosomes.
DNA (Deoxyribonucleic Acid) contains all the information for cells to live, perform their
functions and reproduce.
Inside the nucleus is another organelle called the nucleolus. The nucleolus is responsible for
making ribosomes.
The circles on the surface of the nucleus are the nuclear pores. These are where ribosomes
and other materials move in and out of the cell.
The Cytoplasm
Diagram showing the internal contents of Cytoplasm
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Cytoplasm refers to the jelly-like material with organelles in it.
If the organelles were removed, the soluble part that would be left is called the cytosol.
It consists mainly of water with dissolved substances such as amino acids, vitamins and
nutrients in it.
Cellular Organelles
Mitochondrion
Diagram showing the electron micrograph of a mitochondrion
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Mitochondria are membrane-enclosed organelles distributed throughout the cytosol of most
eukaryotic cells.
Their main function is cellular respiration in which y convert the potential energy of food
molecules into ATP.
Every type of cell has a different amount of mitochondria. There are more mitochondria in
cells that have to perform lots of work, for example- your leg muscle cells, heart muscle cells
etc. Other cells need less energy to do their work and have less mitochondria.
Diagram showing the internal structure on a mitochondrion
Structure of Mitochondrion
Mitochondria have:
 an outer membrane that encloses the entire structure
 an inner membrane that encloses a fluid-filled matrix
 between the two is the intermembrane space the inner membrane is elaborately folded with
shelf like cristae projecting into the matrix.
Ribosomes
Diagram showing the structure of a ribosome
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Ribososmes are organelles that help in the synthesis of proteins.
Ribosomes are made up of two parts, called subunits.
They get their names from their size. One unit is larger than the other so they are called large
and small subunits.
Both these subunits are necessary for protein synthesis in the cell. When the two units are
docked together with a special information unit called messenger RNA, they make proteins.
Some ribosomes are found in the cytoplasm, but most are attached to the endoplasmic
reticulum. While attached to the ER, ribosomes make proteins that the cell needs and also
ones to be exported from the cell for work elsewhere in the body.
Endoplasmic Reticulum
Diagram showing the structure of the endoplasmic reticulum
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It is a network of membranes throughout the cytoplasm of the cell.
There are two types of ER.
When ribosomes are attached it is called rough ER and smooth ER when there are no
ribosomes attached.
The rough endoplasmic reticulum is where most protein synthesis occurs in the cell.
The function of the smooth endoplasmic reticulum is to synthesize lipids in the cell.
The smooth ER is also helps in the detoxification of harmful substances in the cell.
Lysosomes
Diagram showing the structure of Golgi and lysosomes.
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Lysosomes receive cellular and endocytosed proteins and lipids that need digesting.
The metabolites that result are transported either by vesicles or directly across the
membrane.
Lysosomes basically function as the cell's recycling compartment
Golgi Complex
Diagram showing the structure of Golgi complex
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It is organelle in the cell that is responsible for sorting and correctly shipping the proteins
produced in the ER.
Just like our postal packages which should have a correct shipping address, the proteins
produced in the ER, should be correctly sent to their respective address.
In the cell, shipping and sorting done by the Golgi complex. It is a very important step in
protein synthesis.
If the Golgi complex makes a mistake in shipping the proteins to the right address, certain
functions in the cell may stop.
Vesicles
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Vesicles- This term literally means "small vessel". This organelle helps store and transport
products produced by the cell.
Some vesicles deliver materials to parts of the cell and others transport materials outside the
cell in a process called exocytosis
Cilia
Diagram showing the structure of Cilia
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Cilia are thread-like projections of certain cells that beat in a regular fashion to create currents
that sweep materials along
Flagella
Diagram showing the structure of flagella
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Flagella may extend to the rear of a cell and push it forward by snakelike wriggling, or stick
out in front and draw it along.
We humans possess both flagella and cilia. Each sperm cell is propelled by a trailing
flagellum that accelerates the little torpedo forward in its quest to fertilize an egg.
Centrosome
Diagram showing the structure of centrosome and centriole
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The centrosome, is an area in the cell where microtubules are produced.
Plant and animal cell centrosomes play similar roles in cell division, and both include
collections of microtubules, but the plant cell centrosome is simpler and does not have
centrioles.
During animal cell division, the centrioles replicate (make new copies) and the centrosome
divides.
Centriole (animal cells only)
Diagram showing the structure of centriole
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Each centriole is a ring of nine groups of fused microtubules. There are three microtubules in
each group. Microtubules (and centrioles) are part of the cytoskeleton.
In the complete animal cell centrosome, the two centrioles are arranged such that one is
perpendicular to the other.
Questions
Question 1:
The following flow chart illustrates the relationship between two important processes found in the cells
of plants.
a.)
Identify the metabolic processes that organelles X and Y control respectively.
(2)
b.)
Name the carbohydrate that is formed by X and used by Y.
(1)
c.)
Provide labels for parts A, B and C.
(3)
d.)
Give ONE structural adaptation of each organelle and describe how this enables the
organelle to function efficiently.
(4)
[10]
Question 2:
The following diagram illustrates a light microscope used in a Life Sciences laboratory to study
microscopic structures. Study the diagram and answer the questions.
a.)
The table below contains a list of labels in column A. Match the letters in the diagram with the
correct labels and write the letter in column B.
Column A
i.
Objective lens
ii.
Fine adjustment knob
iii.
Body tube
Column B
(3)
b.)
The table below contains a list of different functions in column A. Match the letters in the
diagram with the correct function and write the letter in column B.
Column A
i.
This part moves the body tube to focus the object
clearly.(big movement)
ii.
The lower lenses, which are moveable, allowing
you to view objects under different magnification.
iii.
This part reflects light onto the slide.
Column B
(3)
Question 3:
Consider the following mind map:
Write a paragraph using the mind map above.
Ensure that you include all the topics and bullet points in the mind map.
Your paragraph should not be longer than one page.
The following rubric will be used to mark your paragraph.
Criteria
Ability to
express
themselves
scientifically
Biological
correctness
and use of
terminology.
1
2
3
Facts not
clear and not
linked. Many
grammatical
errors.
Confusion.
Many
biological
errors.
Some flaws of
information.
Some clear
facts. Few
errors.
Vague
understanding
and
interpretation
of mind map.
Clear facts,
but not all
linked yet.
Some errors.
Adequate
understanding
and
interpretation
of mind map.
4
Improved
linking of
facts. Few
errors of
impact.
Almost
everything
biologically
correct.
Links
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Magnification simulation http://www.cellsalive.com/howbig.htm
Animal / Plant Cell http://www.cellsalive.com/cells/cell_model.htm
3D animation of a cell: http://www.xvivo.net/the-inner-life-of-the-cell/
5
Facts clearly
expressed
and linked.
No errors.
Mind map
perfectly
understood
and
interpreted.
Additional
info used.
Total