1. Chapter 3 Cell Structure and Function

2. Eukaryotic Cell Structure

3. Chemical Components of Cells
Most cells are composed of 4 elements
Carbon
Hydrogen
Oxygen
Nitrogen
Cells are about 60% water

4. Anatomy of a Generalized Cell
Cells have 4 main regions (parts)
Nucleus
Cytoplasm
Plasma Membrane

5. Nucleus Control center Cell reproduction DNA --Visible Chromosomes
Nuclear envelope
Double membrane
Pores
Nucleoli
rRNA and tRNA assembly

6. Cell Membrane-fluid mosaic
Controls movement into and out of the cell
Composed of
lipid and protein bilayer
Cholesterol
Glycolipids
Glycoproteins

7. Components of Cell Membrane (Fluid Mosaic Model)
Phospholipids (bilayer)
Phospholipids
Hydrophillic (water loving) Head: Phosphate and glycerol
Hydrophobic Tails (water hating): impermeable to most water soluble molelcules
Cholesterol – membrane fluidity
Proteins: Receptors, enzymes, transport channels or carriers
Receptors: Glycoproteins and Glycolipids
Blood type, organ transplant rejection

8. ORGANELLES
Specialized cellular compartments
Many membrane bound

9. Cytoplasm (Cytosol) Semi-fluid material suspends other elements
Contains enzymes

10. Mitochondrion Double membrane Cellular Respiration!!! Energy for cell
Internal folds
Cellular Respiration!!! Energy for cell
Contains its own DNA and RNA

11. Ribosomes Site of Protein synthesis Found free in cytoplasm
As a part of the Rough ER

12. Endoplasmic Reticulum
Fluid Filled Tubules
Rough ER
Contains Ribosomes
Moves proteins within cell
Smooth ER
No Ribosomes
Protein modification
Lipid metabolism

13. Rough ER

14. Golgi Apparatus Flattened sacs
Modifies, Sorts, and packages proteins arriving from ER for delivery

15. Golgi Animation
Materials are transported from Rough ER to Golgi to the cell membrane by VESICLES

16. 3 types of packages

17. Lysosomes Intracellular digestion (enzymes)
Membranous “bags” from golgi apparatus
Fuse with vesicles
Ingested food
Damaged organelles
Tay-Sachs disease-missing or inactive lysosomal enzymes

18. Cytoskeleton Protein network made of… Cell Shape Internal Organization
Microfilaments
intermediate filaments
Microtubules
Cell Shape
Internal Organization
Organelle Movement!

19. (b) Intermediate filaments (c) Microtubules
Figure 3.7 Cytoskeletal elements support the cell and help to generate movement.
(a) Microfilaments
(b) Intermediate filaments
(c) Microtubules
Tubulin subunits
Fibrous subunits
Actin subunit
10 nm
25 nm
7 nm
Microfilaments form the blue batlike network.
Intermediate filaments form the purple network surrounding the pink nucleus.
Microtubules appear as gold networks surrounding the cells’ pink nuclei.

20. Centrioles Rod shaped made of Microtubules
Before mitosis-pairs duplicate + separate
Produces Mitotic Spindles

21. Cilia and Flagella Cell movement Movement of materials along surface
Sperm cells-flagella
Movement of materials along surface
Respiratory tract-cilia
Microvilli – fingerlike extensions
Increase surface area for absorption

22. Cilia Moving Away Dust Particles from the Lungs Respiratory System

23. Membrane Transport Two basic methods
Passive Transport (no energy required)
Active Transport (energy required ATP)

24. Passive Transport Diffusion Simple: lipid soluble or small
Osmosis: water moves thru
aquaporins
Facilitated: use carriers
Filtration

25. Passive Transport: Filtration
Water and solutes are forced through a membrane because of a pressure gradient
Through capillary walls
Movement of water or small solutes
Kidneys-blood filtration

26. Active Transport Solute pumping Requires protein carriers ATP used
Examples: sodium/potassium pump

27. Active Transport Endocytosis: into the cell
Phagocytosis: engulfing large particles
Pinocytosis: cell drinking
Exocytosis: movement out of the cell

28. Figure 3.12b Exocytosis.
(b) Electron micrograph of a secretory vesicle in exocytosis (190,000×)

29. Figure 3.13b Events and types of endocytosis.
Cytoplasm
Extracellular fluid
Bacterium or other particle
Pseudopod
(b)

30. Figure 3.13a Events and types of endocytosis.
Slide 4
Extracellular fluid
Cytosol
Plasma membrane
Vesicle
Lysosome 1
Vesicle fusing with lysosome for digestion
Release of contents to cytosol 2
Transport to plasma membrane and exocytosis of vesicle contents
Detached vesicle
Ingested substance
Membranes and receptors (if present) recycled to plasma membrane 3
Pit
(a)

31. Cell Life Cycle INTERPHASE CELL DIVISION Cell growth
Carries on regular cell activities
CELL DIVISION
Cell replicates itself to produce more cells for growth and repair

32. Interphase G1: “growth” S: “synthesis” phase G2:
protein synthesis, organelles double
S: “synthesis” phase
DNA replication/duplicated chromosomes
G2:
Protein synthesis, chromatin condenses, chromosomes visible, final preparation to divide

34. Cell Division Mitosis – division of the nucleus
Result: 2 daughter nuclei
Cytokinesis – division of the cytoplasm
Result: 2 daughter cells

35. Figure 3.15 Stages of mitosis.
Slide 1
Centrioles
Chromatin
Centrioles
Spindle microtubules
Centromere
Forming mitotic spindle
Centromere
Plasma membrane
Nuclear envelope
Chromosome, consisting of two sister chromatids
Fragments of nuclear envelope
Spindle pole
Nucleolus
Interphase
Early prophase
Late prophase
Metaphase plate
Nucleolus forming
Cleavage furrow
Nuclear envelope forming
Spindle
Sister chromatids
Daughter chromosomes
Metaphase
Anaphase
Telophase and cytokinesis

36. Cytokinesis
Division of cytoplasm
Cell pinched into 2 daughter cells

37. Protein Synthesis (into) (into) DNA  mRNA  Protein
transcription translation

38. Figure 3.16 Protein synthesis.
Slide 1
Nucleus (site of transcription)
DNA
Cytoplasm (site of translation) 1
mRNA specifying one polypeptide is made on DNA template. 2
mRNA leaves nucleus and attaches to ribosome, and translation begins.
Amino acids
mRNA
Nuclear pore
Nuclear membrane
Correct amino acid attached to each species of tRNA by an enzyme
Synthetase enzyme 4
As the ribosome moves along the mRNA, a new amino acid is added to the growing protein chain.
Growing polypeptide chain
Met 3
Incoming tRNA recognizes a complementary mRNA codon calling for its amino acid by binding via its anticodon to the codon.
Gly
Ser
Phe
Ala
Peptide bond 5
Released tRNA reenters the cytoplasmic pool, ready to be recharged with a new amino acid.
tRNA “head” bearing anticodon
Large ribosomal subunit
Codon
Direction of ribosome advance; ribosome moves the mRNA strand along sequentially as each codon is read.
Portion of mRNA already translated
Small ribosomal subunit