CHAPTER 2 The Chemistry of Living Things

1
LECTURE OUTLINES
CHAPTER 3Structure and FunctionOf Cells
2
Cells Are Classified by Internal Organization

• Eukaryotes have
• plasma membrane
• nucleus information center
• cytoplasm fluid within membrane
• organelles structures with specialized functions
• Prokaryotes have no nucleus or true
  organelles(pro before, kary nucleus)
• Prokaryotes are the bacteria (Kingdom Monera)

Slide 3.1
3
Cell Structure Reflects Cell Function

• Muscle cells contain numerous organelles
  providing energy needed for muscle contraction
• Nerve cells are long and thin to carry impulses
  over distance
• Cells of renal tubule lining are cube-shaped
  (helps with their function of absorption/secretion
  )

Slide 3.2
4
The Plasma Membrane
self markers
Fluid Mosaic Model of Plasma Membrane
Figure 3.4 Slide 3.3
.
5
Structural Features of the Plasma Membrane

• Lipid bilayer
• Phospholipids polar head and nonpolar tail
• Cholesterol makes membrane a bit more rigid
• Proteins provide means of transportation through
  membrane and receptor proteins
• Carbohydrates recognition patterns for cells and
  organisms (self markers to avoid immune system
  attack)
• Stem cells lack these self markers

Slide 3.4
6
Diffusion Passive Transport Through Membrane

• Passive transport no energy required
• Diffusion movement from area of
  highconcentration to low

Figure 3.5 Slide 3.5
7
Osmosis Diffusion of Water

• Osmosis net diffusion of water across a
  semi-permeable membrane

Figure 3.6 Slide 3.6
8
Three Forms of Passive Transport

• Passive transport is powered by the concentration
  gradient. In the cell it occurs as
• diffusion through lipid layer
• diffusion through protein channels
• facilitated transport transport or carrier
  proteins in membrane assist moving molecules
  across the membrane, down the concentration
  gradient, without expending energy

Slide 3.7
9
Three Types of Passive Transport
10
Active Transport

• Active transport requires energy to move
  substances from area of lower concentration to
  area of higher concentration.

Figure 3.8 Slide 3.8
11
Endocytosis and Exocytosis Move Materials in Bulk

• Endocytosis moves material into cell

• Exocytosis moves material out of cell

Figure 3.9 Slide 3.9
.
12
Receptor Proteins in Active Transport

• Receptor proteins span membrane
• Receptor site binds specific molecule

Figure 3.10 Slide 3.10
13
Active Transport The Sodium/Potassium Pump

• Sodium/potassium pump expels unwanted ions,keeps
  needed ones, maintains cell volume
• ATP used to expel three sodium ions for every two
  potassium ions brought into the cell
• Increase cell volume increase water in
  cytoplasm by decreasing the pump and allowing
  more sodium inside cell
• Decrease cell volume less water in cytoplasm by
  increasing the pump and expelling more sodium ions

Slide 3.11
14
Tonicity
Figure 3.12 Slide 3.12
15
Variations in Tonicity

• Isotonic extracellular and intracellular ionic
  concentration equal
• Hypotonic extracellular ionic concentration less
  than intracellular
• Hypertonic extracellular ionic concentration
  more than intracellular

Slide 3.13
16
Internal Structures of an Animal Cell
Figure 3.13 Slide 3.14
17
Structure and Function of the Nucleus

• Functions
• Contains the genetic information of the cell
• Controls the cell
• Structural features
• Double-layered nuclear membrane
• Nuclear pores mRNA travels through these
• Chromosomes/chromatin
• Nucleolus site of RNA production

Slide 3.15
18
Endoplasmic Reticulum (ER) and Ribosomes

• Ribosomes used in protein assembly
• Free and membrane bound
• Endoplasmic Reticulum (ER) packages the proteins
• Smooth ER no ribosomes, lipid synthesis
• Rough ER has ribosomes, protein manufacture

Slide 3.16A
19
Endoplasmic Reticulum (ER) and Ribosomes (cont.)
Figure 3.15 Slide 3.16B
20
Golgi Apparatus

• Receives substances from ER, refines and packages
  them (UPS Station of the cell)

Figure 3.16 Slide 3.17
21
Vesicles Ship and Store Cellular Products

• Vesicles storage, secretory membrane-bound
  spheres
• Examples secretory, endocytic, peroxisomes,
  lysosomes

Figure 3.17 Slide 3.18
22
Mitochondria Provide Energy to the Cell

• Double membrane inner membrane contains enzymes
  that catabolize glucose, fats and proteins
• Liberated energy used to create ATP

Figure 3.18A Slide 3.19
23
Energy Storage

• Fat triglycerides, long-term energy storage in
  animals
• Glycogen short-term energy storage in animals,
  carbohydrate storage
• In liver and very small amt. In muscles

Slide 3.20
.
24
Cytoskeleton Supports the Cell

• Microtubules
• Microfilaments

Figure 3.19 Slide 3.21
25
Cell Structures for Support and Movement Cilia,
Flagella, Centrioles

• Cilia and flagella movement
• 9 2 microtubule arrangement
• Centrioles used in cell division

Figure 3.20 Slide 3.22
.
26
Cells Use and Transform Matter and Energy Two
Basic Metabolic Pathways

• Anabolism requires enzymes
• Making/assembling large molecules
• May require energy (ATP)
• Used in building up cell components
• Used in storing energy
• Catabolism requires enzymes
• Breakdown of molecules
• May release energy
• Used in breaking down nutrients/recycling cell
  components
• Used to access energy storage

Slide 3.23
27
Cellular Respiration Cells Use Oxygen to Supply
ATP

• Glucose provides energy for the cell

Figure 3.22 Slide 3.24
28
Three Stages of Cellular Respiration

• Glycolysis in cytoplasm
• Split glucose (meaning of glyco-lysis)
• Produce 2 ATP and 2 pyruvate molecules
• Krebs cycle in mitochondria
• Extract high energy electrons
• Produce 2 ATP and carbon dioxide
• Electron transport system in mitochondria
• Energy from electrons used to produce ATP
• Produce water and carbon dioxide

Slide 3.25A
29
Three Stages of Cellular Respiration
Figure 3.23 Slide 3.25B
30
Steps in the Electron Transport System
Figure 3.24 Slide 3.26
31
Fats and Proteins Additional Energy Sources
Figure 3.25 Slide 3.27
32
Fats and Proteins Additional Energy Sources

• Fats triglycerides have twice the energy of
  carbohydrates
• Proteins same energy as carbohydrates

Slide 3.28
33
Anaerobic Pathways Energy Extraction Without
Oxygen
Figure 3.26 Slide 3.29