The cell is the lowest level of structure that is capable of performing all the activities of life.

1
Cell Structure and Function
Chapter 4
Early Discoveries

• The cell is the lowest level of structure that is
  capable of performing all the activities of life.
• The first cells- cork, Robert ___________ in
  1665.
• Anton van ________________ - first saw
  single-celled organisms in pond water and
  observed cells in blood and sperm.

• In 1839, Matthais Schleiden and Theodor Schwann
• The ________________- all living things consist
  of cells.
• A cell theory extension - all ______ come from
  other _____.

2
Cell

• Smallest unit of ____
• Can survive _____________ or has potential to do
  so
• Is highly organized for __________
• Senses and responds to ____________
• Has potential to ________________

3
Structure of Cells

• Prokaryotic vs eukaryotic cells

• Differences
• Euks have chromosomes in a ____________(compared
  to a nucleosome in proks.)
• Euks have many _______ __________________
• Eukaryotic cells are __________times larger

• Similarities-
• A ___________________.
• A ______ (semifluid substance) within the cell
• _______________
• __________- organelles that make proteins

• Larger organisms do not generally have
  _______cells than smaller organisms - simply
  _______cells.

4
Lipid Bilayer

• Main component of cell ____________
• Gives the membrane its _____ properties
• Two layers of ______________

Fluid Mosaic Model

• Membrane is a mosaic of
• _______________
• ______________
• Sterols
• _______________

5
Membrane Proteins

• __________proteins
• _________ proteins
• Recognition proteins
• ___________ proteins

Why Are Cells So Small?

• Surface-to-volume ratio
• A bigger cell less _________________ per unit
  volume
• Above a certain size, material cannot be moved in
  or out of cell _____________

6
Fig. 4.5, p. 54
7
Microscopy

• ___________ microscope -minimum resolution is - _
  _______ ( the size of a small bacterium)

For higher resolution- -__________
microscope -Transmission Electron
Microscope -Scanning Electron Microscope
8
Animal cell

• Animal cells lack
• _____________
• _____________
• ______________
• ______________

Fig. 7.7
9

• Plant cells lack
• __________
• ___________
• __________

Plant cell
Fig. 7.8
Most other components are __________by plant and
animal cells
10
1. The nucleus

• contains most of the _____ in a eukaryotic cell.
• Some genes are in ___________ and _____________
• separated from the cytoplasm by a ____________
  membrane.
• Protein pores allow large macromolecules and
  particles to pass through.
• ______________ (located internal to the
  membrane)- maintains nuclear __________

11

• ___________ (DNA and associated proteins)
• Each eukaryotic species has a characteristic
  number of _________________.
• A typical human cell has 46 chromosomes, but sex
  cells (eggs and sperm) have only 23 chromosomes.

• ___________- densely stained fibers and granules
  adjoining chromatin
• Factory for ribosomal RNA (rRNA)
• rRNA is a component of ______________

12
2. Ribosomes build a cells proteins

• _____________-
• contain _______ (from nucleolus) and
  __________.
• composed of two subunits
• carry out __________ synthesis.

Fig. 7.10
13
Ribosomes- (cont.)

• Found in _______locations-
• 1. _____ ribosomes -suspended in the cytosol
• Function synthesize ______________ proteins
• 2._____ ribosomes- attached to the outside of
  the __________________________
• Function synthesize __________ proteins and
  ____________ proteins
• Note Ribosomes can shift locations.

14

• The _____________________- includes
• the nuclear envelope
• endoplasmic reticulum
• Golgi apparatus
• lysosomes
• vacuoles
• plasma membrane.
• Where are the membranes produced?? The _____

15
3.The endoplasmic reticulum

• Two regions of ER that differ in structure and
  function.
• _______ ER
• ribosomes attached to the outside
• Packages proteins into ____________________
• __________ ER
• lacks _____________
• Function synthesize lipids, including oils,
  phospholipids, and steroids
• Also _________________ drugs and poisons

Fig. 7.11
16
4. The Golgi apparatus

• Function _________, ____, and ______ cell
  products
• Many transport vesicles from the ER travel to the
  ________ __________________ for modification of
  their contents.

Cis face receiving
Trans face shipping
____ face _______ vesicles from ER ______ face
ships vesicles out
17
5. Lysosomes

• a membrane-bounded sac of ________ enzymes
• functions -digest ________________ (proteins,
  fats, polysaccharides, and nucleic acids).
• Low pH (5.0)

Nucleus

• massive leakage from lysosomes can destroy an
  cell by __________

Lysosome
Fig. 7.13a
18
5. Lysosomes (Cont.)

• The lysosomal enzymes and membrane are
  synthesized by ________ and then transferred to
  the ___________.
• At least some lysosomes bud from the trans
  face of the ______.

Fig. 7.14
19
5. Lysosomes (Cont.)

• Lysosomes can fuse with __________________ or
  another organelle

• Inherited diseases affect _______________
  metabolism
• These individuals lack a functioning version of a
  normal hydrolytic enzyme.
• Result- Lysosomes are engorged with
  ______________ substrates.
• ____________ disease in the liver
• Tay-Sachs disease in the brain.

20
6. Vacuoles

• Vesicles and vacuoles (larger versions) are
  membrane-bound_____ with varied functions.
• ___ vacuoles, from phagocytosis, fuse with
  lysosomes.
• _________vacuoles, found in freshwater protists,
  pump excess water out of the cell.
• __________ vacuoles are found in many mature
  ______cells.
• Functions - stockpiling proteins or inorganic
  ions.,

21
7. Mitochondria and chloroplasts

• Convert energy to forms that cells can use for
  work.
• __________ -site of _______ _____________,
  generating ATP from the catabolism of sugars,
  fats, and other fuels in the presence of oxygen.
• ___________, found in plants and eukaryotic
  algae, are the site of ________________.
• They convert solar energy to chemical energy and
  synthesize new organic compounds from CO2 and H2O.

Mitochondria
Chloroplast
22

• Mitochondria and chloroplasts-
• Are _____ part of the endomembrane system.
• Proteins from ____ ribosomes in the cytosol (and
  a few from their own ribosomes).
• Contain DNA
• Grow and reproduce as ______________ organelles.

• Almost all ____________ cells have mitochondria.
• Cells may contain one to __________________.
• The number of mitochondria is correlated with
  aerobic metabolic activity.

23
FUNCTION
Review
DNA Produce mRNA

• Nucleus

Produce rRNA (for ribosomes)

• Nucleolus

• Ribosomes

Protein synthesis

• Endoplasmic reticulum

Produce membranes
24
Function
Finishes, sorts, and ships _____________
Golgi
Nucleus
digest -__________
Lysosome
Vacuole

• Transport food to lysosome
• Give plants rigidity

• Food vacuole
• Central vacuole (plants)

Mitochondria

• Produce ATP for energy

Chloroplast

• Capture light for energy (only chloroplasts)

25
8. -_______________

• generate and degrade -_______________ (H2O2) in
  performing various metabolic functions
• H2O2 is _______, but the peroxisome has another
  enzyme that converts H2O2 to water.

• Functions
• break ___________ down for fuel.
• __________ alcohol (and other harmful compounds).
• Convert the fatty acids in seeds to sugars
• Not part of __________- system

26
9. Cytoskeleton

• The ____________ is a network of _______
  extending throughout the cytoplasm.
• ________
• Organizes the structures and activities of the
  cell.
• provides __________ support and maintains shape
  of the cell.
• provides ____________ for many organelles and
  cytosolic enzymes
• dynamic

Fig. 7.20
27
9. Cytoskeleton (Cont.)

• There are three main types of fibers in the
  cytoskeleton
• ______________
• ________________
• __________________.

microfilaments
(Actin)
Fig. 7.21b
Intermediate filaments
(Keratin)
28
10. Cell wall Plant and proks, but not animal
cells

• Function in plants _____________, maintains its
  shape, and prevents excessive uptake of water.
• It also supports the plant against the force of
  ____________.

Plasma membrane

• Composed of microfibrils of _______ embedded in
  a matrix of proteins and other polysaccharides.
• steel-reinforced concrete analogy

29
11. The extracellular matrix (ECM)

• Function- support, adhesion, movement, and
  regulation
• Animals cells have an elaborate ____.
• -_________ fibers embedded in a network of
  ________________
• The _______ connect the ECM to the
  _______________.

• Can influence the activity of genes in the
  nucleus via a combination of chemical and
  mechanical signaling pathways.
• This may coordinate all the cells within a
  tissue.

30
12. ____________________

• Function- Cell to cell communication and
  cell-cell contact
• Plant cells are perforated with ______________,
  channels allowing cysotol to pass between cells.

Animal have 3 main types of intercellular links
Fig. 7.28 inset
31
Prokaryotic Cells

• __________________ and Eubacteria
• DNA is NOT enclosed in ____________
• Generally the smallest, ___________ cells
• No _______________

32
Prokaryotic Structure
pilus
cytoplasm with ribosomes
DNA
flagellum
capsule
cell wall
plasma membrane