Transcript C42: A Closer Look at Cells

7C42: A Closer Look at Cells
Background
• Schleiden & Schwann discovered all living
organisms are made of one or more cells.
• Microbes are often made of just one cell.
• What do you see in microscopic cells?
Typical Cell
• Scientists noticed structures inside cells.
• Some structures are found in nearly all cells.
• These are often in models of a typical cell.
Cell Membrane
• Cell membrane is the most common structure.
• Membrane separates cell from environment.
• Acts as barrier to control what goes in & out.
Cytoplasm:
draw this 
• Material enclosed by the membrane is called
cytoplasm, which means “cell material”.
• In the cytoplasm the cell breaks down
nutrients from food and builds the new
substances it needs to grow and to carry out
its other functions.
Nucleus
• Nucleus is the dark center found in the cells of
most organisms except bacteria.
• It is a small compartment within the cell
separated by a nuclear membrane.
• It contains the genetic information of the cell
and directs its activities, including growth and
reproduction.
Organelles
• Organelles are “little organs” that help cells do
many jobs.
• Often surrounded by their own membranes.
• Some of the jobs include obtaining and storing
energy, helping cells move and divide, and
making substances that are either used in the
cell or transported to other parts of the body.
C42 Draw Cell Assignment, pC59
• On separate paper Draw, Label, and Color
Figure 1 on page C59 from your textbook.
• Under that write Cell Membrane and then
describe its function.
• Next write Cytoplasm & describe its function.
• Then write Nucleus and describe its function.
• Why is Nucleus so important to most cells?
• What organism does not contain a nucleus?
Cell Structure
Cellular Hierarchy Levels
• From largest to smallest these include:
– Body (organism)
– Organ system (like digestive system)
– Organ (stomach)
– Tissue
– Cell
– Organelles
– Macromolecule
– Molecule/Atom
Studying Cells: AIDS
• AIDS is a disease of one group of cells within
the human body. Knowing how the cells work
normally and what goes wrong in the cells of a
person with AIDS helps scientists understand
the disease and develop treatment.
Blood
• Red blood cells live for about 120 days.
• New cells form as old ones die.
• Knowing how they develop helped us make a
drug that causes more red blood cells to form.
• It is given to patients who need certain
surgeries or to patients who have illnesses
that reduce their numbers of red blood cells.
• They make more cells & need less transfusions
Cell Biology
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Branch of Biology studies how cells work. Also:
What each part of the cell does, and how.
How do cells communicate, and their timing.
How can one human cell grow into an adult.
How a cell knows when to divide.
C42 Close Look at Cells Analysis
Do problems #1-4 on page C62 in the textbook
1. Match pictures to descriptions a, b, c, and d
2. Match pictures in #1 to cell types listed
3. Give one example of how the study of cells
helps treat diseases. Explain in 1 paragraph.
4. Explain in 1 paragraph why membranes are
so important to cells.