Download 03-03_pptlect

Anatomy & Physiology
SIXTH EDITION
Chapter 3, part 3
An Introduction to
The Cellular Level of
Organization
PowerPoint® Lecture Slide Presentation prepared by
Dr. Kathleen A. Ireland, Biology Instructor, Seabury Hall, Maui, Hawaii
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Frederic H. Martini
Fundamentals of
SECTION 3-4
The Nucleus
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
The nucleus is the center of cellular operations
• Surrounded by a nuclear envelope
• Perinuclear space
• Communicates with cytoplasm through nuclear
pores
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.13 The Nucleus
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.13
Contents of the nucleus
• A supportive nuclear matrix
• One or more nucleoli
• Chromosomes
• DNA bound to histones
• Chromatin
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.14 Chromosome Structure
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.14
The genetic code
• The cells information storage system
• Triplet code
• A gene contains all the triplets needed to code for
a specific polypeptide
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Gene activation and protein synthesis
• Gene activation initiates with RNA polymerase
binding to the gene
• Transcription is the formation of mRNA from
DNA
• mRNA carries instructions from the nucleus to
the cytoplasm
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.16 An overview of Protein Synthesis
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.16
Translation is the formation of a protein
• A functional polypeptide is constructed using
mRNA codons
• Sequence of codons determines the sequence
of amino acids
• Complementary base pairing of anticodons
(tRNA) provides the amino acids in sequence
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.17 The Process of Translation
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.17
Figure 3.17 The Process of Translation
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.17
SECTION 3-5
How Things Get Into and Out of Cells
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Permeability
• The ease with which substances can cross the cell
membrane
• Nothing passes through an impermeable
barrier
• Anything can pass through a freely permeable
barrier
• Cell membranes are selectively permeable
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Diffusion
• Movement of a substance from an area of high
concentration to low
• Continues until concentration gradient is
eliminated
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.18 Diffusion
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.18
Figure 3.19 Diffusion across the Cell Membrane
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.19
Osmosis
• Diffusion of water across a semipermeable
membrane in response to solute differences
• Osmotic pressure = force of water movement into
a solution
• Hydrostatic pressure opposes osmotic pressure
• Water molecules undergo bulk flow
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.20 Osmosis
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.20
Tonicity
• The effects of osmotic solutions on cells
• Isotonic = no net gain or loss of water
• Hypotonic = net gain of water into cell
• Hemolysis
• Hypertonic = net water flow out of cell
• Crenation
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.21 Osmotic flow across a cell
membrane
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 3.21