Cells Flashcards
They carry out all chemical activities needed to sustain life.
Cells and Tissues
They are the building blocks of all living things.
Cells
They are groups of cells that are similar in structure and function.
Tissues
Anatomy of the Cell:
- Cells are not all the same
- All cells share general structures
Cells are organized into three main regions:
- Nucleus
- Cytoplasm
- Plasma membrane
It is the control center of the cell; it contains genetic material (DNA).
Nucleus
The 3 regions of the nucleus:
- Nuclear membrane
- Nucleolus
- Chromatin
It is the barrier of the nucleus consisting of a double phospholipid layer.
Nuclear membrane
It contains nuclear pores that allow for the exchange of material with the rest of the cell.
Nuclear membrane
The nucleus contains one or more _________.
nucleoli
It is the site of ribosome production; ribosomes then migrate to the cytoplasm through nuclear pores.
Nucleoli
It is composed of DNA and protein and is scattered throughout the nucleus.
Chromatin
Chromatin condenses to form ____________ when the cell divides.
chromosomes
The barrier for cell contents; contains protein, cholesterol, and glycoproteins.
Plasma membrane
The plasma membrane consists of a double phospholipid layer which has:
- Hydrophilic heads
- Hydrophobic tails
Polar heads that are attracted to water.
Hydrophilic heads
Nonpolar fatty acid tails that avoid water and line up in the center of the membrane.
Hydrophobic tails
Finger-like projections that
increase surface area for absorption.
Microvilli
The 3 membrane junctions are the following:
- Tight junctions
- Desmosomes
- Gap junctions
These are impermeable junctions
that encircle the cells and bind them together into leakproof sheets. (Found in the small intestine)
Tight junctions
These are anchoring junctions scattered like rivets along the sides
of adjacent cells. They prevent cells subjected to mechanical stress (such as heart muscle cells and skin cells) from being pulled apart.
Desmosomes
They function mainly to allow communication. These junctions are commonly found in the heart and between embryonic cells.
Gap junctions
These are hollow cylinders composed of proteins that connect neighboring cells.
Connexons
Material outside the nucleus and inside the plasma membrane; the factory of the cell.
Cytoplasm