Download bio 12 chem sept 21

UNIT A: Cell Biology
Chapter 2: The Molecules of Cells
Chapter 3: Cell Structure and Function: Section 3.2
Chapter 4: DNA Structure and Gene Expression
Chapter 5: Metabolism: Energy and Enzymes
Chapter 6: Cellular Respiration
Chapter 7: Photosynthesis
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Chapter 3: Cell Structure and Function
Chapter 3: Cell Structure and Function
In this chapter, you will learn about how cell structures have critical roles to play in the health of an organism.
What other cellular organelles have a similar function to the lysosome?
Why doesn’t the cell “clean up” the faulty lysosomes?
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Chapter 3: Cell Structure and Function
Section 3.2
3.2 Eukaryotic Cells
Eukaryotic cells are structurally complex, distinguished by the presence of a nucleus, which contains the
genetic material. They also contain organelles, which are sub-cellular structures with defined functions.
Structures include the plasma membrane, cytoplasm, cell wall, nucleus, ribosomes, endoplasmic
reticulum, Golgi body, lysosomes, vesicles, mitochondria, chloroplasts, and cytoskeleton
Animals, plants, fungi, and protists are composed of eukaryotic cells
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Chapter 3: Cell Structure and Function
Section 3.2
Figure 3.3 Animal cell anatomy.
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Chapter 3: Cell Structure and Function
Section 3.2
Figure 3.4 Plant cell anatomy.
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Chapter 3: Cell Structure and Function
Plasma Membrane and Cytoplasm
All cells are surrounded by a plasma membrane (cell membrane) consisting of a phospholipid bilayer
embedded with protein molecules. The cell membrane separates the living contents of the cell from the
surrounding environment.
Inside the cell is a semi-fluid medium called the cytoplasm, composed of water, salts, and dissolved
organic molecules.
The cell membrane regulates the entrance and exit of molecules into and out of the cytoplasm.
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From Figure 3.3 Animal cell anatomy.
UNIT A
Chapter 3: Cell Structure and Function
Section 3.2
Cell Walls
Some eukaryotic cells have permeable but protective cell walls in addition to cell membranes. Many plant cells
have primary and secondary cell walls.
primary cell walls contain cellulose
secondary cell walls contain lignin; some fungi have chitin
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From Figure 3.4 Plant cell
anatomy.
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Chapter 3: Cell Structure and Function
The Nucleus
The nucleus stores genetic information.
Chromatin contains DNA and proteins
Condensed chromatin forms chromosomes
The nuclear envelope separates the nucleus from the cytoplasm and contains nuclear pores
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Figure 3.5 Anatomy of the nucleus.
Section 3.2
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Chapter 3: Cell Structure and Function
Ribosomes
Ribosomes are responsible for protein synthesis.
Composed of large and small subunits, as well as rRNA
Associate with mRNA during protein synthesis
Can be found as polyribosomes (several associated with a single mRNA)
From Figure 3.3 Animal cell anatomy.
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Section 3.2
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Chapter 3: Cell Structure and Function
The Endomembrane System
The endomembrane system is the transportation and processing centre of the cell. It consists of
The nuclear envelope
The endoplasmic reticulum (ER): a system of membranous channels and sacs, where proteins are
synthesized and processed (rough ER) and phospholipids are made (smooth ER)
The Golgi apparatus: the “shipping centre” of the cell
Lysosomes and vacuoles (larger storage units, more prominent in plant cells)
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Section 3.2
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Chapter 3: Cell Structure and Function
Section 3.2
Figure 3.6 Endoplasmic reticulum (ER). Ribosomes are present on rough ER, which consists of flattened sacs, but not on
smooth ER, which is more tubular. Proteins are synthesized and modified by rough ER, whereas smooth ER is involved in
lipid synthesis, detoxification reactions, and several other possible functions
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Chapter 3: Cell Structure and Function
Section 3.2
The Golgi Apparatus
The Golgi apparatus: flattened sacs where collection, packaging, and distribution of proteins and lipids
occurs
Produces lysosomes, which contain hydrolytic digestive enzymes and act as the garbage disposal for the
cell
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From Figure 3.3 Animal cell anatomy. The Golgi Apparatus.
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Chapter 3: Cell Structure and Function
Figure 3.7 The Endomembrane
System
Section 3.2
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Chapter 3: Cell Structure and Function
Section 3.2
Peroxisomes
Peroxisomes, similar to lysosomes, are membrane-bound vesicles that enclose enzymes.
Typically peroxisomes contain enzymes that produce hydrogen peroxide, which is a toxic molecule that is
broken down by an enzyme to oxygen and water
Peroxisomes are most prevalent in cells that synthesize and break down fats, for example in the liver
Figure 3.8 Peroxisomes. Peroxisomes contain one or more enzymes that can oxidize various organic substances.
Peroxisomes also contain the enzyme catalase, which breaks down the hydrogen peroxide (H2O2) that builds up after
organic substances are oxidized.
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UNIT A
Chapter 3: Cell Structure and Function
Section 3.2
Energy-Related Organelles
Chloroplasts and mitochondria specialize in converting energy to a form the cell can use.
chloroplasts use solar energy to synthesize carbohydrates (photosynthesis)
mitochondria break down carbohydrates to produce energy in the form of ATP (cellular respiration)
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Chapter 3: Cell Structure and Function
Section 3.2
Chloroplasts
Present in plant and algae cells
Bound by two membranes that enclose the fluid-filled stroma
Within the stroma are thylakoids stacked as grana (chlorophyll in the thylakoid used for photosynthesis)
Figure 3.10 Chloroplast
structure.
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Chapter 3: Cell Structure and Function
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Section 3.2
Mitochondria
Present in all eukaryotic cells
Bound by two membranes that enclose the matrix, a fluid-filled region that contains
ribosomes and DNA
Inner membrane folds in on itself to form cristea
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Figure 3.12 Mitochondrion
structure
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Chapter 3: Cell Structure and Function
Section 3.2
Cont’d on next
slide
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Chapter 3: Cell Structure and Function
Section 3.2
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Chapter 3: Cell Structure and Function
Check Your Progress
Explain the function of the cell wall in eukaryotes.
2. Explain the function of select organelles within the cell.
3. Describe the advantages that different compartments provide for the cell.
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Section 3.2
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Chapter 3: Cell Structure and Function
Section 3.2
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Chapter 3: Cell Structure and Function
Section 3.2
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Chapter 3: Cell Structure and Function
Section 3.2