Download Cell Powerpoint

Cell Structure & Function
•Robert Hooke (1600s) named the cell
after viewing cork under m’scope
At 40x tattoo ink in dermis of skin
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
2 Types of Cells
• Prokaryotes: earliest cells;
Have NO NUCLEUS
• Eukaryotes: modern cells/most
cells( all but bacteria)
HAVE A NUCLEUS
Fig. 6-6
Fimbriae
Nucleoid
Ribosomes
Plasma membrane
Bacterial
chromosome
Cell wall
Capsule
0.5 µm
(a) A typical
rod-shaped
bacterium
Flagella
(b) A thin section
through the
bacterium
Bacillus
coagulans (TEM)
Sickle Cell Anemia
*note misshapen RBC
Cell Theory
1. All living things are made of
cells.
2. Cells are the basic unit of life
3. New cells come from existing
cells
-Schleiden, Schwann, Virchow
Functions of Organelles
Cytoplasm
(Cytosol)
• Thick, clear gel-like substance
found throughout cell
• Supports the organelles
Nucleus
• “control center” of cell
• Contains the chromosomes
(genetic info.= DNA*)
• Has all instructions to make new
proteins
• *DNA from both parents found
here
Nucleolus
• Center of nucleus
• Site of ribosome synthesis
(ribosomes are made here)
Fig. 6-UN1a
Structure
Cell Component
Concept 6.3
The eukaryotic cell’s genetic
instructions are housed in
the nucleus and carried out
by the ribosomes
Nucleus
Function
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.
Two subunits made of ribosomal RNA and proteins; can be
free in cytosol or bound to ER
Protein synthesis
(ER)
Ribosome
Fig. 6-10
Nucleus
1 µm
Nucleolus
Chromatin
Nuclear envelope:
Inner membrane
Outer membrane
Nuclear pore
Pore
complex
Surface of
nuclear envelope
Rough ER
Ribosome
1 µm
0.25 µm
Close-up of nuclear
envelope
Pore complexes (TEM)
Nuclear lamina (TEM)
Chromosomes
• Contain genetic
information/DNA
• Chromatin combines to form
• Humans have 46
chromosomes or 23 pairs
Fig. 15-1
Fig. 15-5
X
Y
Endoplasmic Reticulum
• Extensive system of tubules
and membranes
– 2 Types:
1.Smooth ER
2.Rough ER
Smooth ER
• Synthesis of lipids (cholestrol)
• Breaks down/metabolizes
carbohydrates
• Packages enzymes for secretion
• De-toxification of alcohol in liver
ER
Fig. 6-12
Smooth ER
Rough ER
ER lumen
Cisternae
Ribosomes
Transport vesicle
Smooth ER
Nuclear
envelope
Transitional ER
Rough ER
200 nm
Fig. 6-11
Cytosol
Endoplasmic reticulum (ER)
Free ribosomes
Bound ribosomes
Large
subunit
0.5 µm
TEM showing ER and ribosomes
Small
subunit
Diagram of a ribosome
Rough ER
• Has ribosomes attached
• One of the sites of protein
assembly
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
Cell Membrane
(plasma membrane)
•Support
•Protection
•Regulates which substances
enter & exit = Selectively
permeable
Fig. 6-7
Outside of cell
Inside of
cell
0.1 µm
(a) TEM of a plasma
membrane
Carbohydrate side chain
Hydrophilic
region
Hydrophobic
region
Hydrophilic
region
Phospholipid
Proteins
(b) Structure of the plasma membrane
Fig. 6-30
Collagen
Proteoglycan
complex
EXTRACELLULAR FLUID
Polysaccharide
molecule
Carbohydrates
Fibronectin
Core
protein
Integrins
Proteoglycan
molecule
Plasma
membrane
Proteoglycan complex
Microfilaments
CYTOPLASM
What might ENTER a cell?
• Oxygen
• Dissolved nutrients
• Potassium and other ions
• water
Vacuoles
• Storage of
–Water
–Dissolved nutrients
–Even Waste
**animals have few, very small
Fig. 6-15
Central vacuole
Cytosol
Nucleus
Central
vacuole
Cell wall
Chloroplast
5 µm
Central Vacuole
• Plants have a large central
vacuole.
• Takes up most of plant cell
–Supports
–Turgor Pressure
–“Wilting” process: how?
Nuclear Membrane
• Protects nucleus (why
necessary?)
• Has Nuclear Pores: holes to
allow substances to enter/exit
Lysosomes
• Animal Cells
• Bags of hydrolytic enzymes
• Digests old cell organelles
Cytoskeleton
• System of protein fibers
• (Microtubules,
microfilaments)
1. Gives cell shape
2. Supports cell
3. Helps move organelles
Fig. 6-1
Golgi Apparatus
Golgi Body
• Proteins are modified and
packaged here for secretion
• “warehouse/UPS” of cell
• Lysosomes are made here
Fig. 6-13
cis face
(“receiving” side of
Golgi apparatus)
0.1 µm
Cisternae
trans face
(“shipping” side of
Golgi apparatus)
TEM of Golgi apparatus
Fig. 6-16-3
Nucleus
Rough ER
Smooth ER
cis Golgi
trans Golgi
Plasma
membrane
Mitochondria
• “powerhouse of cell”= energy
is produced
• Site of cellular (aerobic)
respiration (ATP is made)
• Was once an independent,
free-living organism
Fig. 6-17
Intermembrane space
Outer
membrane
Free
ribosomes
in the
mitochondrial
matrix
Inner
membrane
Cristae
Matrix
0.1 µm
• 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)
Endosymbiont Theory:
Idea that…..
1. Chloroplasts & mitochondria
were once free-living
2. Moved into eukaryotic cell
3. Became an organelle of cell
Why do we think this?
Both chloroplasts &
mitochondria have:
a) Outer membrane
b) Energy source/function
c) Both have bits of genetic
material
Fig. 6-19
Chloroplast
Peroxisome
Mitochondrion
1 µm
Chloroplast
• Plant Cells
• Located in middle of leaf tissue
• Site of photosynthesis
• green- chlorophyll
• Was once free-living, independent
• *has maternal DNA (interesting!)
Fig. 6-18
Ribosomes
Stroma
Inner and outer
membranes
Granum
Thylakoid
1 µm
Cell Wall
• Plants only
• Support
• Protection
• Made of cellulose: strong
carbohydrate
Fig. 6-28
Secondary
cell wall
Primary
cell wall
Middle
lamella
1 µm
Central vacuole
Cytosol
Plasma membrane
Plant cell walls
Plasmodesmata
Centrioles
• Animal cells
• Helps move chromosomes
apart during mitosis
Cilia and Flagella
• Protein fibers
• Cilia- short fibers; all over
• Flagella- long fibers; 1 or 2
• purpose: locomotion
(movement)
• Ex: paramecium, spermatozoa
Fig. 6-23
Direction of swimming
(a) Motion of flagella
5 µm
Direction of organism’s movement
Power stroke Recovery stroke
(b) Motion of cilia
15 µm
How Are Plant Cells and Animal
Cells Different?
Plants:
• Chloroplasts
• Cell walls
• Central vacuole
• Green: chlorophyll
• None
• Rectangular shape
Animals
• None
• None
• Few, smaller
• None
• Lysosomes
• Different shapes
• More mitochondria