2. Cell Structure & Function

3. Robert Hooke (1600s) named the cell after viewing cork under m’scope

5. At 40x tattoo ink in dermis of skin

8. Comparing Prokaryotic and Eukaryotic Cells
Basic features of all cells:
Plasma membrane
Semifluid substance called cytosol
Chromosomes (carry genes)
Ribosomes (make proteins)
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

9. 2 Types of Cells Prokaryotes: earliest cells; Have NO NUCLEUS
Eukaryotes: modern cells/most
cells( all but bacteria)
HAVE A NUCLEUS

10. A typical rod-shaped bacterium (b)
Fig. 6-6
Fimbriae
Nucleoid
Ribosomes
Plasma membrane
Bacterial
chromosome
Cell wall
Capsule
0.5 µm
Flagella
(a)
A typical rod-shaped bacterium
(b)
A thin section through the bacterium Bacillus coagulans (TEM)
Figure 6.6 A prokaryotic cell

11. Sickle Cell Anemia
*note misshapen RBC

12. Cell Theory All living things are made of cells.
Cells are the basic unit of life
New cells come from existing cells
-Schleiden, Schwann, Virchow

13. Functions of Organelles

14. Cytoplasm (Cytosol)
Thick, clear gel-like substance found throughout cell
Supports the organelles

15. Nucleus “control center” of cell Contains the chromosomes
(genetic info.= DNA*)
Has all instructions to make new proteins
*DNA from both parents found here

16. Nucleolus Center of nucleus Site of ribosome synthesis
(ribosomes are made here)

17. Cell Component Structure Function Fig. 6-UN1a Concept 6.3 Nucleus
Surrounded by nuclear
envelope (double membrane)
perforated by nuclear pores.
The nuclear envelope is
continuous with the
endoplasmic reticulum (ER).
Houses chromosomes, made of
chromatin (DNA, the genetic
material, and proteins); contains
nucleoli, where ribosomal
subunits are made. Pores
regulate entry and exit os
materials.
The eukaryotic cell’s genetic
instructions are housed in
the nucleus and carried out
by the ribosomes
(ER)
Ribosome
Two subunits made of ribo-
somal RNA and proteins; can be
free in cytosol or bound to ER
Protein synthesis

18. Close-up of nuclear envelope
Fig. 6-10
Nucleus
1 µm
Nucleolus
Chromatin
Nuclear envelope:
Inner membrane
Outer membrane
Nuclear pore
Pore complex
Rough ER
Surface of
nuclear envelope
Ribosome
1 µm
0.25 µm
Close-up of nuclear envelope
Pore complexes (TEM)
Nuclear lamina (TEM)

19. Chromosomes Contain genetic information/DNA Chromatin combines to form
Humans have 46 chromosomes or 23 pairs

20. Fig. 15-1
Figure 15.1 Where are Mendel’s hereditary factors located in the cell?

21. Fig. 15-5 X Y
Figure 15.5 Human sex chromosomes

22. Endoplasmic Reticulum
Extensive system of tubules and membranes
2 Types:
Smooth ER
Rough ER

23. Smooth ER Synthesis of lipids (cholestrol)
Breaks down/metabolizes carbohydrates
Packages enzymes for secretion
De-toxification of alcohol in liver ER

24. Smooth ER Nuclear envelope Rough ER ER lumen Cisternae Transitional ER
Fig. 6-12
Smooth ER
Nuclear envelope
Rough ER
ER lumen
Cisternae
Transitional ER
Ribosomes
Transport vesicle
200 nm
Smooth ER
Rough ER
Figure 6.12 Endoplasmic reticulum (ER)

25. Endoplasmic reticulum (ER)
Fig. 6-11
Cytosol
Endoplasmic reticulum (ER)
Free ribosomes
Bound ribosomes
Large subunit
Figure 6.11 Ribosomes
Small subunit
0.5 µm
TEM showing ER and ribosomes
Diagram of a ribosome

26. Rough ER
Has ribosomes attached
One of the sites of protein assembly

27. Ribosomes
Site of protein synthesis
Made of RNA + protein
Means: proteins are made here
Free Ribosomes: NOT attached to ER
Bound Ribosomes: attached to ER

28. Cell Membrane (plasma membrane)
Support
Protection
Regulates which substances enter & exit = Selectively permeable

29. Carbohydrate side chain
Fig. 6-7
(a)
TEM of a plasma
membrane
Outside of cell
Inside of
cell
0.1 µm
Carbohydrate side chain
Hydrophilic
region
Hydrophobic
region
Hydrophilic
region
Phospholipid
Proteins
(b) Structure of the plasma membrane

30. Figure 6.30 Extracellular matrix (ECM) of an animal cell, part 1
Collagen
Proteoglycan
complex
Polysaccharide
molecule
EXTRACELLULAR FLUID
Carbo-
hydrates
Fibronectin
Core
protein
Integrins
Proteoglycan
molecule
Plasma
membrane
Proteoglycan complex
Figure 6.30 Extracellular matrix (ECM) of an animal cell, part 1
Micro-
filaments
CYTOPLASM

31. What might ENTER a cell?
Oxygen
Dissolved nutrients
Potassium and other ions
water

32. Vacuoles Storage of Water Dissolved nutrients Even Waste
**animals have few, very small

33. Central vacuole Cytosol Nucleus Central vacuole Cell wall Chloroplast
Fig. 6-15
Central vacuole
Cytosol
Figure 6.15 The plant cell vacuole
Nucleus
Central vacuole
Cell wall
Chloroplast
5 µm

34. Plants have a large central vacuole. Takes up most of plant cell
Supports
Turgor Pressure
“Wilting” process: how?

35. Protects nucleus (why necessary?)
Nuclear Membrane
Protects nucleus (why necessary?)
Has Nuclear Pores: holes to allow substances to enter/exit

37. Lysosomes
Animal Cells
Bags of hydrolytic enzymes
Digests old cell organelles

38. Cytoskeleton
System of protein fibers
(Microtubules, microfilaments)
Gives cell shape
Supports cell
Helps move organelles

39. Fig. 6-1
Figure 6.1 How do cellular components cooperate to help the cell function?

40. Golgi Apparatus Golgi Body
Proteins are modified and packaged here for secretion
“warehouse/UPS” of cell
Lysosomes are made here

41. (“receiving” side of Golgi apparatus) 0.1 µm
Fig. 6-13
cis face
(“receiving” side of Golgi apparatus)
0.1 µm
Cisternae
Figure 6.13 The Golgi apparatus
trans face
(“shipping” side of Golgi apparatus)
TEM of Golgi apparatus

42. Nucleus Rough ER Smooth ER cis Golgi Plasma membrane trans Golgi
Fig
Nucleus
Rough ER
Smooth ER
cis Golgi
Figure 6.16 Review: relationships among organelles of the endomembrane system
Plasma membrane
trans Golgi

43. Mitochondria
“powerhouse of cell”= energy is produced
Site of cellular (aerobic) respiration (ATP is made)
Was once an independent, free-living organism

44. in the mitochondrial matrix
Fig. 6-17
Intermembrane space
Outer membrane
Free ribosomes
in the mitochondrial matrix
Inner membrane
Cristae
Figure 6.17 The mitochondrion, site of cellular respiration
Matrix
0.1 µm

45. More active cells have more mitochondria- WHY?
Ex: muscle cells have more
Has a membrane surrounding
And DNA of its own!
mtDNA- inherited from mother/materlineal
Used in forensics (sometimes)

46. Endosymbiont Theory:
Idea that…..
Chloroplasts & mitochondria were once free-living
Moved into eukaryotic cell
Became an organelle of cell

48. Why do we think this?
Both chloroplasts & mitochondria have:
Outer membrane
Energy source/function
Both have bits of genetic material

49. Chloroplast Peroxisome Mitochondrion 1 µm Figure 6.19 A peroxisome

50. Chloroplast
Plant Cells
Located in middle of leaf tissue
Site of photosynthesis
green- chlorophyll
Was once free-living, independent
*has maternal DNA (interesting!)

51. Inner and outer membranes
Fig. 6-18
Ribosomes
Stroma
Inner and outer membranes
Granum
1 µm
Thylakoid
Figure 6.18 The chloroplast, site of photosynthesis

52. Cell Wall Plants only Support Protection
Made of cellulose: strong carbohydrate

53. Secondary cell wall Primary cell wall Middle lamella Central vacuole
Fig. 6-28
Secondary cell wall
Primary cell wall
Middle lamella
1 µm
Central vacuole
Cytosol
Figure 6.28 Plant cell walls
Plasma membrane
Plant cell walls
Plasmodesmata

54. Centrioles
Animal cells
Helps move chromosomes apart during mitosis

55. Cilia and Flagella
Protein fibers
Cilia- short fibers; all over
Flagella- long fibers; 1 or 2
purpose: locomotion (movement)
Ex: paramecium, spermatozoa

56. Direction of organism’s movement
Fig. 6-23
Direction of swimming
(a) Motion of flagella
5 µm
Direction of organism’s movement
Figure 6.23a A comparison of the beating of flagella and cilia—motion of flagella
Power stroke
Recovery stroke
(b) Motion of cilia
15 µm

57. How Are Plant Cells and Animal Cells Different?
Plants:
Chloroplasts
Cell walls
Central vacuole
Green: chlorophyll
None
Rectangular shape
Animals
None
Few, smaller
Lysosomes
Different shapes
More mitochondria