Cells Flashcards
What is a cell?
The smallest functioning unit of an organism, displays characteristics of life.
Cell theory
Life comes from life.
All living things are made of cells.
Main parts of a cell
Cell wall-outer non-living part of plant cells Protoplasm- interior living portion. 1. Nucleus-brain 2. Cytoplasm-fluid part of protoplasm 3. Organelles-little organs
Different kinds of cells
Prokaryotic
Eukaryotic
Prokaryotic Cell
Small, simple cells. Lack nucleus Lack most other organelles. Structurally simple. Bacteria
Eukaryotic cell
Everything else…plants, animals, fungi and algae.
Have nucleus.
Have a variety of organelles
Prokaryotic cell size
1-2 microns
Eukaryotic cell size
10-200 microns
Why are cells small?
They get their nutrients through their cell membranes.
Cell description…
- Membrane
- Plasma membrane (specific)
- Other membrane organelles
E.R.
Golgi apparatus
Lysosomes
Vacuoles/ Vesicles
Nuclear membrane
Mitochondria
Chloroplasts - Nonmembranous organelles
Ribosomes
Cytoskeleton
Cilia and flagella
Inclusions - Nucleus
Other cell membrane components are?
Proteins- surface and embedded
Cholesterol-hydrophobic
Found within the hydrophobic tails
Keeps the membrane flexible
Plasma membrane
Composed of a single phospholipid bilayer
Separates the contents of the cell from environment
Endoplasmic Reticulum (ER)
Set of folded membranes and tubes.
Provides a large surface area for important chemical reactions
Two types of E.R.
Rough- has ribosomes on its surface.
Sites of protein synthesis
Smooth- lacks ribosomes
Metabolizes fats
Detoxifies
Golgi apparatus
Stacks of flattened membrane sacs.
Modifies molecules
Manufacturers polysaccharides and lipids
Packages and ships molecules
Lysosomes
Made in the golgi
Vesicles containing enzymes that digest macromolecules
Destroy old, damaged organelles
Peroxisomes
Helps detox harmful molecules
“ase” enzyme
Vacuoles
Membrane-enclosed sacs, storage.
Large
Vesicles
Membrane-enclosed sac
Smaller
The nuclear membrane
Separates the genetic material from the rest of the cell.
Filled with nucleoplasm
Composed of two bilayers
Contains holes called nuclear pore complexes
Interconversion of membranes
Membranes are converted from one membranous organelle to another
Mitochondrion
Powerhouse of cell
Small bag with lg bag stuffed inside
Chloroplasts
Mostly plants (some bacteria)
Contains chlorophyll
Performs photosynthesis
Non membranous organelles
Ribosomes Cytoskeleton Centrioles Cilia flagella Inclusions
Ribosomes
Made of DNA
Found free floating in cytoplasm
Attached to Endoplasmic reticulum
Cytoskeleton
Provides shape, support and movement.
Made up of microtubules
Microfilaments
Intermediate filaments
Centrioles
Two sets of microtubules arranged at right angles to each other.
Located in a region called centrosome
Flagella
Hair-like projections extending from cell. Long, few in number. Moves through environment.
Cilia
Hair-like projection
Small and numerous. Moves the environment past cell (like boat oars)
Inclusions
Collections of miscellaneous materials
“Granules”
Temporary sites for the storage of nutrients and waste
Nuclear components
Brain of cell Contains chromatin DNA and proteins Surrounded by nuclear membrane Contains one or more nucleoli Contains nucleoplasm
Diffusion
Molecules are in constant, random motion
Molecules move from areas of high concentrations to low.
Involves a concentration gradient
How quick does diffusion happen?
The rate of diffusion depends on the size of the molecule and the size of the concentration gradient.
(The greater the concentration difference, the faster the diffusion)
Diffusion across membranes
Diffusion can only happen if there is no barrier to the movement of molecules.
Can only happen across a membrane that is permeable.
Direction of diffusion
Determined solely by the concentration gradient.
Diffusion is passive that does not require energy input
Osmosis
The diffusion of through a selectively-permeable membrane.
Occurs when there is a difference in water concentration on opposite sides of the membrane.
Water will move to the side where there is less water
Hypertonic
Less water
Hypotonic
Cell has more water
Hypo—> Mo
Facilitated diffusion
Diffusion with help.
Active transport
Requires energy.
Moves molecules across a membrane UP their concentration gradient
Endocytosis
Moves large molecules or sets of molecules into the cell
Phagocytosis
Cell eating
Pinocytosis
Cell drinking
Exocytosis
Moves large molecules or sets of molecules out of the cell
