Cell Structure

1

• Cell Structure

2
I. Looking at Cells

• A. Scientists only became aware of cells after
  the invention of the microscope.
• 1. 1665Robert Hooke observed cork cells
• and called them little boxes.
• 1675Anton van Leeuwoenhoek used a
• microscope and observed pond water. He
• discovered many living creatures.

3
B. Measuring Cell Structures

• 1. Measurement taken by scientists are expressed
  in Metric Units. The official name of the metric
  system is International System of Measurements.
• The metric system is based on powers of 10.

4
(No Transcript)
5
fill in the metric chart.
6
C. Types of Microscopes

• 1. Compound Light Microscope
• The most powerful Light microscopes can magnify
  up to 2000X.
• 2. Electron Microscope
• Electron microscopes can magnify up to 200,000X.
• Transmission Electron Microscopes (TEM) reveal
  internal details.
• Scanning Electron Microscopes (SEM) shows 3-D
  images of surface.

7
Eyepiece
Body Tube
Revolving Nosepiece
Objectives
Arm
Stage Clip
Stage
Course Adjustment
Diaphragm
Fine Adjustment
Light
Base
8

• Eyepiece lens closest to the viewers eye
• Body Tube directs light from the objective to
  the eye
• Revolving nosepiece hold the objectives
• Arm holds the base of the microscope with the
  objectives and eyepiece
• Stage Clips hold the slide in place
• Stage supports the slide

9

• Course Adjustment used to bring an object into
  focus under LOW power
• Fine Adjustment used to fine tune the focus
  under LOW and HIGH power
• Base holds the light source, connects to the
  arm to hold the other parts of the microscope
  together
• Objective more magnification of the objective
• Light source light source
• Diaphragm controls the amount of light that
  travels through the specimen

10
TAKS QUESTION

• The English scientist Robert Hooke used a crude
  microscope to examine
• A. individual atoms C. single-celled organisms
• B. electrons D. cork cells

11
II. Cell Theory

• A. Whose observations helped form the CELL
  THEORY?
• 1838- Mattias Schleiden concluded that cells make
  up every part of the Plant.
• 1839- Theodor Schwann concluded that animals are
  made up of cells.
• 1858- Rudolph Virchow determined that cells only
  come from other cells.

12
B. 3 parts of the Cell Theory

• 1. All living things are made up of one or more
  cells.
• 2. Cells are the basic units of structure and
  function in organisms.
• 3. All cells arise from existing cells.

13
CELL SIZE

• Small cells function more efficiently than large
  cells.
• How many cells are our bodies made up of? 100
  trillion
• The advantage of cells being smaller is that
• substances that enter or leave a cell must
  cross that cells surface if the cell is small
  they can exchange substances more readily than
  large ones.

14
Relationship between Surface area and Volume
15
Common Features of Cells

• Cell Membrane- outer boundary of cell
• Function- regulates what enters and leaves the
  cell
• Made up of- phosphoplipids and proteins
• Cytoplasm- fills the cellcellparts are suspended
  in this
• Function- same as above
• Made up of- water and salts

16
(No Transcript)
17

• Cytoskeleton- a system of microscopic fibers
• Function- provides framework, shape and support
• Made up of- protein fibers

18

• Ribosomes- proteins are made here
• DNA- found in the nucleus
• Function- provides instructions for making
  proteins, regulates cell activities
• Made up of- nucleotides

19
5. Prokaryotes

• Smallest and simplest cells.
• Prokaryote- is a single-celled organism that
  LACKS a nucleus and other compartments
• They were the only organisms on Earth for 2
  billion years. They are very simple and small.
  The familiar prokaryotes that cause infection and
  cause food to spoil are commonly called Bacteria.

20
Characteristics of Prokaryotes

• They can live everywhere.
• They can cause infection in humans and grow and
  divide very rapidly.
• Some do not need oxygen survive.
• Some can make their own food.
• Prokaryotic cells have cytoplasm,cell wall,
  ribosomes, cell membrane DNA (circular). Some
  have flagella for movement.
• Some prokaryotic cell walls are surrounded by a
  capsule that enables the cell to cling to almost
  anything.

21
.
22
6. Eukaryotic Cells

• A eukaryote is an organism whose cells have a
  nucleus.
• Organelle-parts of the cell that carry out
  specific activities
• Nucleus-internal compartment that holds DNA
• Function- controls cells activities

23

• Cilia-short hair-like structures
• Function-used for movement
• Cytoskeleton- provides interior framework
• Function- support and shape of the cell
• Made up of- protein fibers microfilaments,
  microtubules, intermediate fibers

24
6. Cell Membrane

• Cell Membrane- selective permeability (barrier)
• Made up of- phospholipids and proteins
• Draw a picture below of the Cell Membrane-
  Phospholipid and a Lipid bilayer

25
(No Transcript)
26
7. Membrane Proteins

• Serve many roles including as markers as
  receptors to recognize and bind to substances as
  enzymes as transport proteins to move substances
  across the membrane
• TAKS Question
• A bacterium that lost its flagella would be
  unable to
• A. divide C. maintain its shape
• B. move D. make proteins

27
III. Cell Organelles

• The Nucleus
• Contains Hereditary information- DNA RNA
• RNA- made in nucleus used to make proteins
• DNA- wound tightly into chromosomes
• Humans have 46 chromosomes. Garden peas have 14
  chromosomes.

28
(No Transcript)
29
B. Endoplasmic Reticulum-system of internal
membranes

• Function- moves proteins and other substances
  through the cell
• Made up of- lipid bilayer embedded proteins
• Rough ER- contains ribosomes
• Smooth ER- (lacks ribosomes)-makes lipids and
  breaks down toxins

30

• C. Golgi Apparatus- flattened membrane- bound
  sac
• Function- package and distribution center (UPS)
• Made up of- proteins
• D. Lysosomes- vesicles that bud off of Golgi
  Apparatus
• Function-contains cell digestive enzymes
• E. Mitochondria- MIGHTY MITOCHONDRIA-site of
  cell metabolism
• (more mitochondriamore energy)
• Function-makes energy ATP for the cell
• Made up of- 2 membranes-inner is folded out and
  outside is smooth.

31
F. Structures of Plant Cells--------3 structures
found only in PLANT CELLS.

• 1. Cell Wall- surrounds the cell membrane
• Function- support maintains shape of the cell
  
• Made up of- proteins, carbohydrates-gtcellulose
• 2. Chloroplasts- found in plant cells as well as
  algae
• Function-use light energy to make
• Carbohydrates -gtglucose
  (sugar)
• Made up of- 2 membranes has own DNA
• 3. Central vacuole- takes up most of a plant
  cells volume
• Function-stores water ,nutrients, wastes (when
  full cell wall is rigid)

32
(No Transcript)
33
TAKS Question

• Which organelle serves as the packaging and
  distribution center of a eukaryotic cell?
• A. Nucleus C. MitochondrionB. Lysosome D.
  Golgi Apparatus