Unit 2 Flashcards
Cell Theory
- All living things are made up of 1
or more cells. - Cells are the smallest working
units of all living things. - All cells come from pre-existing
cells through cell division.
Cell (Def.)
A cell is the smallest unit that
is capable of performing life
functions.
Unicellular
An organism made up of one cell.
Multicellular
An organism composed of multiple cells.
Prokaryotes
Cells that do not have a nucleus or membrane-bound organelles (bacteria).
Eukaryotes
Cells that have a nucleus and organelles (ex: plants, fungi, protista, animals)
Organelles
Cell structures that have a specific
function and are surrounded by a
membrane that are found in eukaryotes
only.
Cell Wall Function
Found outside of the
cell membrane in
plant cells & bacteria
only. Contains cellulose (carb)
that provides support
(rigidity) & protection.
Cell Membrane Function
A bi-layer surrounds the cells and controls the movement in and out of cells. There is a receptor on the outside of the plasma membrane that lets things into the cell. It has phospholipids which are held together through the cholesterol bonds. The protein channel lets things in and out of the cell membrane. In plants and bacteria, it is within the cell wall.
Cytoplasm Function
The cytoplasm is a gel-like mixture inside cells and is surrounded by the cell membrane. It contains the cell structure that carries out specific jobs (ex. Mitochondrion, nucleus) and it provides a medium for chemical reactions to take place.
Nucleoid (Only Prokaryotes)
A region in the cytoplasm that contains a singular, circular chromosomal DNA. Plasmids, smaller circular DNA, are also located in the cytoplasm.
Ribosomes
Are contained on the rough ER and throughout the cytoplasm. The ribosomes make proteins. There are thousands in each cell.
Nucleus
Organelle: Contains the genetic material (DNA) within a nuclear membrane and directs the cell’s activities.
Nuclear Membrane
Organelle: Work just like the cell membrane, but they surround the nucleus, which holds the DNA. The nuclear membrane is made up of two layers and can allow certain materials into the nucleus through pores.
Chromatin
Metabolic Organelle: Is located within the nucleus and is the genetic material in the non-divided state (chromosomes). The chromatin is practically uncoiled chromosomes that contain instructions for traits and characteristics (DNA-genes).
Nucleolus
Organelle: A dark staining feature inside of the nucleus that makes ribosomes.
Rough Endoplasmic Reticulum (ER)
Organelle: Network of continuous sacs, studded with ribosomes. The rough ER is the internal delivery system of the cell that manufactures, processes, and transports proteins (made by ribosomes) for export from the cell. The rough ER continues from the nuclear envelope
Smooth Endoplasmic Reticulum (ER)
Organelle: Also continues from the nuclear membrane and is similar in appearance to the rough ER, but the smooth ER doesn’t contain ribosomes. The smooth ER produces lipids, involved in carbohydrate metabolism, and detoxification of drugs and poisons.
Golgi Apparatus
Organelle: prepares the proteins and lipids created in both the ERs for export from the cell. The golgi apparatus encloses digestive enzymes (lipase, amylase etc.) into membranes to form lysosomes (the waste removers [removes proteins, lipids, and carbs]).
Lysosome
Organelle: Created by the golgi apparatus by enclosing waste materials (protein, lipids, and carbs) with a digestive enzyme inside the membrane. It breaks down cellular waste and debris and transports undigested material to the cell membrane to be removed.
If a lysosome explodes,
the cell breaks down.
If cholesterol concentration (or levels) are high,
then things can’t be produced by the cell or exported out of the cell because the cell membrane is stiff (non-functioning).
Mitochondria
Organelle: Mitochondria generate the chemical energy needed to power the biochemical reactions of the cell. They are the site of cellular respiration, which is the use of glucose to create cell energy. They are membrane-bound organelles that have inner and outer membranes.
Active cells (like muscles) have
more mitochrondria
Animal Vacuole
Organelle: A membrane-bound organelle that is used for storage, digestion, and waste-removal. They contain a water solution.