Transcript of the cell - MrMsciences

Section 2.1
Cell Structures and
Types of Cells
Cell Compartmentalization
Organelles of an Animal Cell
Structure- parts of a cell visible through a
light microscope
Ultrastructure- parts of a cell visible through
only an electron microscope
Plasma Membrane- “wall and gate” of the
cell; 7nm wide
•Selective permeability - allows some
molecules to pass through while keeping
others out.
•Transport proteins- special tunnels or
doors that only let in specific molecules
The Nucleus
• The “brain” of the cell
• Contains loosely coiled
DNA (Chromatin)
• Nucleolus- Compact,
largely inactive DNA in
chromosome form
Ribosomes
Ribosomes• Factories of the Cell
•Take copy of DNA’s
information (mRNA) and use
it as a guide to create proteins
from amino acids
• ER ribosomes- proteins
move on to Golgi
apparatus
• Free ribosomes- proteins
move to cytoplasm
Golgi Apparatus
Golgi Apparatus- membrane sacs that put proteins into small
packages called vesicles which are sent out or around the cell;
makes lysosomes
Lysosomes- sacs of hydrolytic enzymes that digest old
organelles, food, and viruses/bacteria
The Mitochondria
• power house of the cell; produces ATP (energy unit
for cells) by breaking down sugars and other organic
compounds
•Two membranes with inner one folded many times
•Matrix (inner area) produces ATP and lipids
Organelles for Support
Cytoplasm- clear gel-like fluid inside cells; help holds
organelles in place
Cytoskeleton- “Bones” of the cell; crossing rods, filaments,
and
tubes, that hold the cells shape. Also act at a
“train” system to move things around the cell
Cilia and Flagella
Flagella- long, wipe-like
tail that pushes and rolls
the cell
• Move in long strokes
Cilia- short, hair-like
paddles that push the cell
along
• Move in short fast
beats all at same time
Organelles of a Plant Cell
•The organelles already covered
can also be found in plant cells
•Plants have a few extra organelles
Cell wall- thick, rigid wall
made of cellulose that gives
the plant cell a definite shape
Plasmodesmata- small
connecting points between the
cells walls of neighboring
plant cells; allow exchange
Photosynthesis Centers
Chloroplasts- perform photosynthesis to make energy from
sunlight in planets and some unicellular
organisms
Chlorophyll- chemical that absorbs wavelengths of sunlight,
expect green
Grana- stacks of membranes containing chlorophyll
Vacuoles- Both Large and Small
Vacuoles- storage compartments for food, enzymes, etc.
• In plant cells- they are very large and hold lots of water
and nutrients; tonoplast membrane controls exchange;
also holds pigments the give flowers color
• Creates turgid pressure to keep plant up right
• In animal cells- very small; transport things inside the
cell
Animal Cells Vs. Plant Cells
Organelle
Plants only
Animals only
Plasma
Membrane
Cell Wall
Both
X
X
Nucleus
X
Ribosomes
X
Gogi Apparatus
X
Cilia/Flagella
(Extremely
Rare)
X
Lysosome
Vacuole
X
(large)
Mitochondria
Chloroplasts
(small)
X
X
X
Specialization of Cells
• Specialized Cells cells with
physical features that allow them to
do specific jobs
• Ciliated cells
• found in your throat and lungs
• cilia on one side push material
in certain direction
• cilia + mucus = dust trapper
•Root hair cells
• found on the roots of plants
• increase surface area of cell so it
can absorb more water/minerals
• Major theme in biology!
• mitochondria, root cells,
intestine, brains… all have many
folds!
Specialization of Cells
• Xylem vessels
• empty waterproof tubes that allow
movement of water/minerals through
out the plant
•Muscle cells
• long, thin fibers that can shrink
(contract) and expand (relax)
• Allow all movement and support for
skeleton
•Red blood cells
• contain haemoglobin; protein with
Fe2+ ions that can transport O2 and
some CO2
• Reason blood is red
• Flat round discs allow for movement
in body and exchange of gasses
Limits of Light
Eye Piece
Mag
Objective
Mag
10x
4x
10x
40x
100x (oil
emmersion)
Mag and Res Practice
700nm line between VL/Infrared
Resolution = ½ radiation used
0.5 * 700nm 350nm
9mm 9000μm
9000 μm / 75,000 = 0.12 μm (120nm)
120nm = 0.5 x wavelength of radiation
Wavelength= 240 nm (UV light)
Homeostasis: Happy Cells
• In single-celled organisms this is not
very difficult
• In multi-celled, complex organisms there
are many levels to organize:
• Cells Single unit of life; can be specialized
for a specific job (muscle cell)
• Tissue Groups of the same cells working
together to do a specific job (muscle tissue)
• Organ Tissues grouped together to do a
specific job (heart)
• System Organs and extra parts working
together for a specific job (Circulatory
system)
Tissues Working Together
•Plant tissue:
•Upper epidermis water proof outer
covering; covered with cuticle
•Palisade mesophyll photosynthetic cells
•Spongy mesophyll space for CO2
circulation
•Phloem transport solutes
•Xylem transport water and salts
•Lower epidermis stomata for gas
exchange
Homework
• Read all of Unit 2
• Unit 2 Vocab is due
on Sunday (Friday
schedule)
• Questions on p. 19
and p. 23
• Organelle
Worksheet