Cell Structure and Function

1
Chapter 7

• Cell Structure and Function
• (Aligned with 7.1 Intro Sheet and 7.2 Cell
  Structure Chart)

IMPORTANT My hope is that you will use this on
your computer as a way to ensure that your chart
is filled in completely. If you MUST print it
out, please make sure you print SIX SLIDES PER
PAGE!! Save a tree!!
2
7-1 Life is Cellular
A. Cells basic units of structure and function
in living things
3
B. Early scientists that led to the cell theory

• Anton van Leeuwenhoek (1600s) given credit for
  developing the 1st mini microscope, looked at
  pond water and made detailed drawings
• Robert Hooke coined the term cell when he
  looked at slices of cork and dead plant cells
• Robert Brown (1833) observed a dark structure
  near the center of the cell (we now know this is
  the nucleus)
• Matthias Schleiden (1838) stated all plants are
  made of cells
• Theodore Schwann (1839) stated all animals are
  made from cells
• Rudolph Virchow (1855) - stated all cells come
  from the division of preexisting cells
• Lorenz Oken stated all new cells are the result
  of division of preexisting cellsVIRCHOW STOLE
  HIS THUNDER

4
C. Cell Theory

• All living things are composed of cells.
• Cells are the basic units of structure and
  function in living things.
• All cells come from preexisting cells.

5
7-2 Cell Structure

• Cellular Control Center
• Nucleus, nucleolus, chromatin/chromosomes,
  nuclear membrane/pore
• Organelles that Store, Clean Up and Support
• Vacuoles, vesicles, lysosomes, cytoskeleton
  (microtubules, microfilaments), centrioles
• Organelles that Build Proteins
• Ribosomes, endoplasmic reticulum (smooth and
  rough), golgi apparatus
• Organelles that Capture and Release Energy
• Chloroplasts, mitochondria
• Cellular Boundaries
• Cell wall, cell membrane
• Fluid Portion Outside of Nucleus (Sort of a
  boundary!)
• cytoplasm

6
CELLULAR CONTROL CENTER NUCLEUS

• Function
• Information center of the cell
• Contains DNA (chromatin vs. chromosomes)
• Directs cell activities
• 2 categories of organisms
• Prokaryotes organisms whose cells lack nuclei
  (i.e. bacteria)
• Eukaryotes organism whose cells contain nuclei

7
Nucleus

• Structure
• NUCLEOLUS a small, darkened region in the
  nucleus that is made up of RNA and proteins, this
  is where ribosomes are made
• CHROMOSOMES large structures formed from DNA
  that contain the genetic info
• CHROMATIN uncondensed DNA found in non-dividing
  cells
• NUCLEAR ENVELOPE double membrane around the
  nucleus that contains pores, allows molecules to
  move in and out of the nucleus, and protects the
  nucleus
• NUCLEAR PORES allows passage of materials into
  or out of nucleus (RNA, ribosomes)

8
Nucleus
9
ORGANELLES THAT STORE, CLEAN UP, SUPPORT VACUOLE

• Structure
• Large, central structure in plants
• Many, small, circular structures in animal cells
• Filled with liquid
• Function
• Storage of water, salts, proteins, carbohydrates,
  waste products
• Pressure system for plants, prevents wilting
• Special case contractile vacuole - prevents
  excess water intake, leading to cell-bursting

10
ORGANELLES THAT STORE, CLEANUP, SUPPORT VESICLE

• Store and move materials between cell organelles
  and to/from cell surface

11
ORGANELLES THAT STORE, CLEAN UP, SUPPORT
LYSOSOME

• Structure
• Small, circular structures
• Found only in animal cells
• Contain digestive enzymes
• Function
• Digestion of
• Worn out organelles
• Debris
• Large ingested particles
• Lysosomes are responsible for your hands not
  being webbed!!

12
Lysosome
13
ORGANELLES THAT STORE, CLEAN UP, SUPPORT
CYTOSKELETON

• Structure
• Hollow tubes of proteins
• Examples cilia, flagella, centrioles
• Function
• Framework
• Provide cell with support, structure and shape
• Movement (cilia, flagella)
• Microfilaments - allow movement of cytoplasm
  within the cell (cytoplasmic streaming)
• Microtubules - Maintain cell shape, make up
  cilia, flagella and centrioles

14
(No Transcript)
15
ORGANELLES THAT STORE, CLEAN UP, SUPPORT
CENTRIOLES

• Organize cell division

16
ORGANELLES THAT STORE, CLEAN UP, SUPPORT
PLASTID

• Structure
• Differ based on type of plastid (chloroplast is
  one example)
• Found only in plants
• Function
• Store food/starch
• Store pigments (give color to fruits veggies)

17
ORGANELLES THAT BUILD PROTEINS RIBOSOMES

• Structure
• Small (25 nm) ball-like structures
• Found free-floating in cytoplasm or attached to
  rough endoplasmic reticulum
• Composed of RNA and protein
• Function
• Synthesis of proteins (where proteins are made)

18
ORGANELLES THAT BUILD PROTEINS ENDOPLASMIC
RETICULUM

• Structure
• Network of flattened sacs
• Can be rough (w/ ribosomes) or smooth (w/o)
• Function
• Transport materials within or out of cell
• Synthesis of macromolecules
• Rough - proteins, lipids, carbs
• Smooth - lipids

19
ORGANELLES THAT BUILD PROTEINS GOLGI APPARATUS

• Structure
• Flattened stacks of membranes
• Vesicles attached to top and bottom
• Function
• Collection, modification, packaging of proteins
  and other substances
• Vesicles attach, deposit materials
• GA modifies materials based on needs
• Vesicles attach to membrane and distribute
  modified substances

20
(No Transcript)
21
ORGANELLES THAT CAPTURE/RELEASE ENERGY
CHLOROPLAST

• Structure
• Double membrane
• Elaborate structure inside
• Function
• Another power station
• Found in plant cells only
• Conversion of light energy (sun) into chemical
  energy (glucose)

22
ORGANELLES THAT CAPTURE/RELEASE
ENERGYMITOCHONDRIA

• Structure
• Double membrane
• Cristae - inner folds, increase surface area
• Outer membrane for protection of cell
• Function
• Powerhouse of the cell
• Able to self-replicate (? in cells with high
  energy need)
• Converts sugars into energy for cells

23
CELLULAR BOUNDRIES CELL WALL

• Only in plants, algae, and some bacteria
• Lies outside the cell membrane
• Function
• Helps to protect and support the cell
• Very porous (water, oxygen, carbon dioxide, etc.
  can pass through easily)
• Gives rectangular shape to plant cells
• Layers
• 1st layer contains pectin (gluey substance that
  helps hold the cells together)
• 2nd layer primary cell wall (made of cellulose)
• 3rd layer (in woody stems) secondary cell wall
  (composed of cellulose and lignin to make
  cellulose more rigid)

24
CELLULAR BOUNDRIESCELL MEMBRANE outer
boundary

• Structure
• Phospholipid bilayer
• hydrophilic heads, hydrophobic tails
• Contains lipids (bilayer), proteins (channels),
  and carbohydrate chains (identification cards)
• Function
• Regulates what enters and leaves the cell
• Semi-permeable membrane
• Protection and support

25
Cell/Plasma Membrane
26
CELLULAR BOUNDRIESCYTOPLASM

• Material between the cell membrane and the
  nucleus
• Contains the organelles of the cell

27
QUESTIONS

• Describe the steps involved in the synthesis,
  packaging, and exporting of a protein from a
  cell.
• Proteins assembled on ribosomes (if targeted for
  export to cm or to specialized locations w/in
  cell, complete their assembly on RER? protein in
  vesicle ? Golgi apparatus (further modifies,
  proteins before sorting and packaging them in
  membrane bound vesicles ? vesicle ? final
  destination
• What are the two major parts of the cell?
• Cytoplasm with organelles, and nucleus
• How do contractive vacuoles help maintain water
  balance?
• Pump out excess water
• What is the difference between rough and smooth
  ER?
• Rough has ribosomes, smooth does not
• Why is the cell membrane sometimes referred to as
  a fluid mosaic? What part of the cell membrane
  acts like a fluid? And what makes it like a
  mosaic?
• It is made of many parts (like a mosaic) that can
  float around in the fluid phospholipid bilayer
• How do the properties of lipids help explain the
  structure of the cell membrane?
• Hydrophilic lipid heads are attracted to water,
  hydrophobic fatty acid tails turn away from
  water. A bilayer forms when heads turn outward
  towards water inside and outside a cell
• Why do you think its important that cell
  membranes are selectively permeable?
• Allows needed substances to enter and wastes to
  leave, while keeping molecules that are not
  needed out

28
Plant vs. Animal Cell
29
Animal Cell
30
Plant Cell