Transcript File - Science with Snyder

Unit 2: Part 1
Cell structure and function
Membrane Functions
Cell Structure and Function
Scientists
Book section 3.1
Hooke – cells
Leeuvenhoek – “animacules”
Shleiden – all plants made up of cells
Schwann – All animals are make up of cells
Virchow – cells come from other cells
The Cell theory has three principles.
1. All living things are composed of one or
more cells.
2. The cell is the most basic unit of structure
of all living things.
• unicellular organisms- one cell
• Multicellular – specialized regions called
tissues.
3. All existing cells are come from previously
existing cells.
• The ability of cells to divide to form new
cells is the basis for all reproduction and
for the growth and repari of all multi
organisms.
Cell Diversity
• Cell Shape – shape induces function
• Cell Size – too big and nothing can get
done. Smaller cells have better
homeostasis
2.3
3 basic parts of all cells
• Plasma membrane – barrier to outside
– Selectively permeable
• Cytoplasm – fluid inside, also includes the
cytoskeleton, and organelles
• Control Center – Either just DNA or
Nucleus.
2 MAIN TYPES OF CELLS
• The major difference between prokaryotic cells
and eukaryotic cells is the presence of a
nucleus.
• 1. prokaryotic cells do not have a true nucleus,
the DNA in pro cell is circular and called
plasmid.
• 2. Eukaryotic cells, the DNA is organized into
structures called chromosomes and the
chromosomes are separated from the
cytoplasm by a nuclear membrane.
PROKARYOTE
– No nuclei
– Can have cell membrane, cell
wall, plasmid (circular DNA)
– Smaller and simpler (size of
mitochondria)
– On Earth before others
– Most bacteria
– Divide by binary fission
(asexual)
Thee are two cell types: eukaryotic cells and prokaryotic cells
2. EUKARYOTES
– Have nuclei
– Higher level membrane bound organelles
– All plants, animal, fungi (all but monera)
– Most are Multicellular, but can be unicellular
– PLANTS AND ANIMALS
Plants
2.2 Cell Organelles and
Features
Organelle: is a cell structure the performs a
specialized function within a eukaryotic cells.
Organelles found in a eukaryotic cell are
mentioned on the next 84 slides.
• 1. Nucleus
– “brain”
– Processes and contains DNA
– Nucleolus – dense section inside nucleus
• Production of ribosome's (protein makers)(rRNA)
– Nuclear envelope – double membrane with
pores to allow passage of RNA and
Ribosome
– Chromatin – loose or granular genetic
material. Most common state of DNA.
• During cell division the chromatin coagulates
together forming chromosomes (threads)
2. Mitochondria
• Sites of cellular respiration, a process that
turns glucose into ATP or energy
• “powerhouse” of cell
• The more active, more mitochondria, you
have in your muscle cells.
• Has own DNA, plasmid
• Found in both plant and animal
3. Chloroplast
- Are found only in plants cells, contain the
green pigment, chlorophyll, which absorbs
energy from the sun to convert CO2 and
H2O into sugar through the process of
photosynthesis.
- Has its own DNA
- Plants do have mitochondria
Vesicles
• 4. Lysosomes – Bud from the GA, filled
with enzymes that break down carbs,
lipids and proteins, also breakdown dead
organelles and waste from cell.
• Peroxisomes – Neutralize free radicals
and detox.
– Produce H2O2 as the break substances down.
5. Vacuoles – large bubbles that store water, salts,
proteins and carbs
Plants have 1 large vacuole, the pressure
within the sac is sole provider for support of
stems and leaves (turgor pressure). When full,
stiff, when empty, limp.
•Some animals have contractile vacuoles.
Large central vacuole
• Contains water and enzymes.
– Controls turger pressure.
6. ribosomes
The sites of protein synthesis; some are located
on the ER, others are found in the cytoplasm.
7. Endoplasmic Reticulum (ER)
- Continuous organelles.
- tubes and sacs - cisternae
– Rough ER – maker of cell membrane
(phospholipids) and proteins (ribosomes)
• Has little balls on the outside
• RER found more in cells that have glands and
secretions.
– Smooth ER – No attached ribosomes.
contains enzymes that perform specialized
tasks. Creates steroids (lipids), helps as a
detox station.
•8. Golgi Apparatus – Stack of membranes that attach
carbohydrates and lipids to proteins (ribosomes)
•Modifies, collects, packages, and distributes proteins
Cytoskeleton
Microfilament – Protein filaments that help the
cell maintain shape
• Crawling of white blood cells.
• Very small
Microtubules – hollow tubes of protein, shape
and give “tracks”
• In cell division of animals, they pair up (centrioles)
and help separate chromosomes
• Also can cluster to form cilia and flagella allow cell
for swim and motion.
• 9. Cilia are tiny hair like projections
responsible for the movement animal cells
or protists.
– Made from microtubules.
• 10. Flagella are long whip like projections
responsible for the movement of some
animal cells, bacteria, or protists.
– Made from microtubules.
11. Plasma Membrane (Cell Membrane)
- protects the cell and regulates the passage of
material between the cell and its environment.
Also provides support.
– Flexible phospholipid bilayer (hydrophilic heads,
hydrophobic tails)
– Knows as a fluid mosaic model.
– Sterols – lipids, in tails, gives shape and protects
during low temps
CM – fluid mosaic model
–Have proteins immersed inside for transport of materials in and out of the cell.
12. Cell Wall
• Surround the cell membrane for protection
and support in plants, bacteria and fungi.
• Made of cellulose – complex
carbohydrates
13. cytoplasm
• The semi – fluid material inside the cell
containing molecules and the organelles.
– Microfilaments and microtubules
• 14. Centrioles – clusters of microtubules
that form an organelle used during mitosis
that secretes fibers that helps to pull the
cell apart during reproduction.