Plasma Membrane

1
(No Transcript)
2
All organisms are made of cells

• Cells conform
• to the definition
• of life

3
CELLS

• Reproduce
• Change with time
• Highly organized

• Obtain energy and materials from their food
• Respond to their environments

4
Invention of the compound Microscopes

• 1595
• credited to Zacharias Janssen
• eyeglasses beginning to be used lots of focus
  great deal of attention to optics and lenses
• probably helped by his father Hans
• slide the draw tube in or out while observing the
  sample

• magnifying images approximately three times when
  fully closed and up to ten times when extended to
  the maximum

5
(No Transcript)
6
First Living Cells

• Discovered by
• Anton von Leewenhoek
• Dutch drapery store owner
• FIRST to OBSERVE and DESCRIBE MICROSCOPIC
  ORGANISMS and LIVING CELLS
• Teeth scrapings animacules

7
Robert Hooke Cork Cells

• 1665
• English Scientist
• thin slice of cork and
• "a great many little boxes"
• reminded him of the small rooms in which monks
  lived, so he called them
• "Cells"

8
To the cell theory

• 1838 German Botanist Schleiden
• 1839 German Zoologist Schwann
• 1855 German Physician Virchow

• studied a variety of PLANTS and concluded that
  all PLANTS "ARE COMPOSED OF CELLS
• reported that ANIMALS are also made of CELLS and
  proposed a cellular basis for all life.
• induced that The animal arises only from an
  animal and a plant only from a plant or cells
  only come from other cells.

9
Cell Theory

• Summary of Schleiden, Schwann, Virchow
• All organisms are composed of one or more
  cellslife processes occur here.
• Cells are the basic unit of structure and
  function of all organisms.
• 3. All cells come from other cells.

10
Spontaneous Generation

• Cell Theory
• Went against the idea that life could arise from
  nonliving matter
• Redifly/meat experiment
• Pasteurbroth experiment

11
All cells share three common features

• PLASMA MEMBRANE (cell membrane) is cells
  boundary
• separates the inside from the rest of the world
• highly organized and responsive
• regulates the cells environment by selecting
  what enters and leaves (like a gated community)

12

• 2. GENETIC INFORMATION for each cell are
  contained in molecules of DNA
• Eukaryotes
• Prokaryotes
• 3. CYTOPLASM
• outside the nucleus but inside the membrane

13
The shape of a cell depends on its function
14
The cells need to regulate its internal
environment limits its size

• Homeostatic regulation of salt concentration and
  pH
• take in useful molecules and dispose of waste

15

• Large cells
• Difficult to maintain just the
• right environment for all of the
• different molecular activities
• This is why most unicellular organisms are
  microscopic.

16
Limits to cell size

• Limited by the RATIO between their Outer Surface
  Area and Their Volume. 
• A SMALL CELL HAS MORE SURFACE AREA THAN A LARGE
  CELL FOR A GIVEN VOLUME OF CYTOPLASM. 
• nutrients, oxygen, and other materials a cell
  requires must enter through it surface

17

• The cells nucleus (the brain) can only control a
  
• certain amount of living, active cytoplasm.

18
How Big Are Cells?
19
Prokaryotic cells Bacteria

• Prokaryote before the nucleus
• Cytoplasmall metabolism here
• No membrane-bound organelles
• DNAcircular not in a nucleus
• Cell wall, cell membrane, ribosomes, nucleoid
  region

20
(No Transcript)
21
Eukaryotic Cells

• true nut
• Nucleus
• Membrane-bound organelles
• Specialized structures
• subdivided

22
Cellular organization has two important benefits

• allows organisms to make a division of
• labor among specialized cells
• allows organisms to outlive the cells that
• compose them

23
Nucleus

• contains genetic instructions for how to make a
  new cell
• Nuclear membrane
• controls the movement of materials in and out of
  the nucleus
• Nuclear Pores

24
(No Transcript)
25
Genetic Information

• coded in DNA and is passed from one generation to
  the next
• chromosomes are composed of chromatin, a complex
  of DNA and protein
• chromosomes are formed when the cell is dividing

26
Cytoplasm/Cytosol

• Cytoplasmfrom the membrane to the nucleus and
  all the stuff in between
• cytosolthe Jell-O like part of the inside of a
  cell
• where most of the work of the cell is done

27

• cytosol makes up 50 of the cells volume
• contains enzymes important to
• building molecules
• breaking small molecules
• making proteins
• also contains glycogen and fat
• organelles, vesicles, and vacuoles embedded within

28
Endoplasmic reticulum

• ER is continuous from the nucleus
• Rough or smooth
• modifies proteinsespecially those being exported
  from the cell
• cells specialized for the production of secreted
  proteins have large amounts of rough ER

29
(No Transcript)
30
Ribosomes

• ribosomes are complexes of RNA and protein (found
  in cytosol)
• tiny, round organelles for protein synthesis

• free ribosomes
• and ER bound
• ribosomes

31
Smooth ER

• Ribosome-free
• synthesize and metabolize lipids
• detoxifies alcohol
• produce steroid hormones

32
Golgi Complex or Bodies

• packages and labels proteins for destinations
  inside/outside the cell
• usually near the nucleus
• of golgi complexes varies
• Found in cells that secrete lots of proteins
  (esp. exported)

• golgi packages them into membrane-bound vesicles

33
Up to 100 a cell!!!
34
Golgi Apparatus at Work
35
Packaging Proteins
36
Lysosomes

• digest wastes and foreign invaders
• made in Golgi apparatus
• the lysosomes membrane keeps it from digesting
  the cytosol

vary in size but all contain enzymes to break
down proteins, nucleic acids, sugars, lipids
37
Peroxisomes

• Found in cells that synthesize, store, or break
  down lipids

• use oxygen to break down molecules that produce
  hydrogen peroxide
• H2O2 is bad for the cell kept inside
• Another enzyme breaks down the hydrogen peroxide
  into water and oxygen

Can occupy half the volume of the cell
38
Mitochondria

• Capture the energy from small organic molecules
  and convert it into the form of ATP
• ATP provides the power to fuel the cells
  chemical reactions
• Outer membrane is smooth inner is folded
  (cristae)

Cells that use a lot of energy have lots of
mitochondria
39
(No Transcript)
40
Chloroplasts

• chloroplastssite of photosynthesis where sugars
  are made and stored large, round, green
  (chlorophyll)
• Chromoplasts--pigments

• turn solar energy into chemical energy through
  photosynthesis
• Type of plastid--plant organelle that is
  surrounded by a double membrane

41
(No Transcript)
42
Vacuoles

• Large membrane-bound sacs without any obvious
  internal structure
• Type of vesicle
• vacuoles up to 95 of cells volume

43
Cytoskeleton
skeletal and muscular system for the cell

• network of protein filaments give structure and
  support to the cytoplasm and its organelles
• provides the force for most of the cellular
  movement and is constantly dissolving and
  reforming

44
(No Transcript)
45
Centrosomes/Centrioles
Help animal cells do that mitosis thingyou know
where they divide and stuff.
46
Plasma Membrane

• Asymmetrical
• phospholipid bilayer
• hydrophobic tail hydrophilic head
• phospholipids arranged head to tail
• proteins throughout contribute to structure and
  function

47
Membranes 4 major roles

• separate the inside from the outside
• regulate the contents of the spaces they enclose
• energy conversions

4. workbench for biochemical reactionsmetabolizi
ng of lipids and secretion of proteins
48
(No Transcript)
49

• hydrophobic barrier, confining hydrophilic
  molecules to the inside or the outside of a cell
• some membrane proteins help transport specific
  molecules across the membrane

• It is fluidproteins and lipids can move freely
  along the plain of the membrane

50
Cell Wall

• Plant cells
• Cellulose (polysaccharides)
• Supports!! Rigid!!
• Protects!!
• Does it allow materials to pass into/out of the
  cell?
• Also bacteria, fungus, some Protista

51
Cilia

• short, hair-like structures
• Helps move stuff along cell (your respiratory
  tract)
• Helps the cell move (pond water organisms)

52
Flagella

• Long whip-like structure
• Helps move cell (sperm)

53
(No Transcript)
54
Tour of Animal Cell
55
(No Transcript)
56
Tour of Plant Cell
57
(No Transcript)