Download 3 Unit 1

Cells
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Unit 1
Chapter 3
Cell Structure
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• Plasma membrane
• Cytoplasm: cytosol + organelles
• Nucleus
Figure 3.1
Cell Membrane
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• Phospholipid bilayer
• Cholesterol
• Proteins
• attached carbohydrates
Figure 3.2
Membrane Function
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Barrier between inside and outside of cell
Controls entry of materials- Transport
Receives chemical and mechanical signals
Transmits signals between intra- and extra
cellular spaces
• Note the various proteins in figure
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Terminology: Body Fluid Pools
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• Intracellular (ICF)
• Extracellular (ECF) ->
• Between cells = Interstitial
• In blood vessels = Plasma
• In lymphatic vessels = Lymphatic
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2/3 of total
Terminology: Solutions
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• Solvent- doing the dissolving
Mostly water
• Solute- material dissolved
• Concentration
• Concentration gradient
Difference in concentration between 2 areas of
solution
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Amount of solute in a given amount of solvent
Figure 3.3
Passive transport: Diffusion
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Requirements for Simple Diffusion
Concentration gradient of solute
Can diffuse across a membrane
either dissolve in the lipid membrane
e.g. O2, C O2, lipid soluble vitamins
Specialized ion channels that can open and shut =
(gated channels)
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• if charged must go through channels
Figure 3.4
Figure 3.5
Facilitated Diffusion
Requires a carrier in membrane
Only goes down concentration gradient
Saturates = maximum speed
Maximum speed dependent on carrier
number
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Figure 3.6
Osmosis
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• Diffusion of water
• Must have a membrane
• Membrane impermeable to a solute
Figure 3.7
Figure 3.8
• Requires a carrier
• Requires energy (ATP)
• Can transport up a concentration
gradient
• Critical for moving important ions
• Major active transport in most cells =
• Sodium-potassium (Na+/K+) pump
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Active Transport
Figure 3.9
Transport in Vesicles
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• Requires energy
• Involves small membrane sac
• Endocytosis- importing materials
• Exocytosis- exporting materials
Table 3.2
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Cytoskeleton- Fig 3.11
Flagella, Cilia & Centrioles- Motion
Endoplasmic reticulum- Fig. 3.14
Golgi apparatus- Fig. 3-15
Mitochondrion- Fig 3-16
Nucleus, nucleolus, nuclear envelopeFig. 3-17
• Vesicles, e.g. lysosome-
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Cell organelles
Cytoplasm
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• Cell contents
• Includes organelles and Cytosol
• Excludes nucleus
• Maintain shape of cell
• locate organelles
• change cell shape
• Includes: microfilments,
intermediate flilments, microtubules
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Cytoskeleton
Figure 3.11
Centrosome
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• Centriole
• Pericentiolar material
Figure 3.12
Cilia and flagella
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• Specialized for motion
• Flagella- single
• Cilia in groups
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Found in respiratory system- move mucus
• Sites of protein synthesis
• Ribosomal RNA (rRNA)
• Ribosomal Proteins
• Can be attached to endoplasmic
reticulum or free in cytosol
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Ribosomes
• Synthesis and intracellular transport
• lipid synthesis- all
• Protein synthesis- rough E.R.
• Protein modification
• transport around cell
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Endoplasmic Reticulum-
Figure 3.14
Golgi Complex
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• Modify and package proteins
• E.g. lipoproteins and glycoproteins
• Some packaged into vesicles=>
• Lysosomes or export by exocytosis
Figure 3.15
Small bodies
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• Lysosomes- contain digestive
enzymes
• Peroxisomes- oxidize for
detoxification
• Proteasomes- digest proteins
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Abundant in liver
Mitochondrial function
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• Energy (ATP) production
• Where oxygen is consumed
• where nutrients are “burned”
Figure 3.16
• Round or oval structure
• Surrounded by nuclear envelope
• Openings = Nuclear pores
• Can include a nucleolus- make
ribosomes
• Store genetic material
• copy information for transfer
to new cells
to the cytosol for protein synthesis
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Nucleus
Figure 3.17 part 1
Figure 3.17 part 2
Protein Synthesis
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• 2 steps
• Nuclear =
transcription
• Cytoplasmic =
translation
Figure 3.19a
Figure 3.19b
Transcription
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• In nucleus
• RNA polymerase transcribes DNA into
RNA=>
• 1. messenger RNA (mRNA)
• 2. Ribosomal RNA
Part of ribosomes
• Transfer RNA (tRNA)
Carries amino acids to ribosome for reaction
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Directs synthesis of polypeptide
Translation
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• Requires 3 different RNAs
• Message RNA -from nucleus
(mRNA)
• Transfer RNA to carry amino acids
(tRNA)
• Ribosomes to do the actual work
containing ribosomal RNA (rRNA)
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Figure 3.20
Figure 3.20 part 1
Figure 3.20 part 2
Figure 3.20 part 3
Figure 3.20 part 4
Figure 3.20 part 5
Figure 3.20 part 6
Cell Cycle
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• Interphase
Growth and development of cell
prepare for reproduction-DNA synthesis,etc.
4 phases
• Cytokinesis= division of cell
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• Mitotic Phase = division of
nucleus and cell
• Centrioles move to opposite ends
• Nuclear envelope disappears
• Chromosomes appear with
centromeres
• Chromosomes move to spindles
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Prophase
Figure 3.21b
Metaphase
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• Chromosomes lined up in center=>
• Metaphase plate
Figure 3.21c
Figure 3.21c
Anaphase
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• Sister chromosomes move to
opposite ends of spindle
Figure 3.21d
Telophase
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• Nuclear envelopes reappear
• Cytokinesis is completed
• May be programmed genetically
• Number of factors contribute
• Protein cross-links by glucose
• Free radical damage
• Cessation of mitosis
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Aging