Transcript Basic Cell Biology

All living things are composed of cells.
Cells are the “building blocks” of living
things.
Each type of cell has a particular role to
play, and the shape of the cell is related to
that role.
Almost all cells contain at least 3 parts:
cell membrane, cytoplasm, and a nucleus.
All cells have a cell membrane, also known as
the plasma membrane.
It is semipermeable, which means it only allows
certain materials to pass through the cell. (Ex: water
& other nutrients needed for life processes)
It also gets rid of waste materials from those
processes that would otherwise build up and harm
the cell.
Molecules in a solution pass through the
membrane from a region of high concentration to a
region of lower concentration. This process is called
diffusion.
Water passes through the semipermeable cell
membrane in a process called osmosis. Water moves
from a region of high concentration to a region of
low concentration.
Osmosis and diffusion allow the cell to remain
constant even though conditions in the environment
change. This ability of an organism to remain stable
when conditions around it change is called
homeostasis.
Cells are filled with a thick, clear fluid that
surrounds the nucleus.
This fluid, cytoplasm, contains all the material
needed by the cell to conduct life processes.
It aids in moving these materials, is constantly
moving, and suspends other parts of the cell.
*It’s what gives the one-celled organisms, like
amoeba, its ability to move.*
Serves as “control center” for all cell activities.
Not all cells have a true nucleus:
- Eukaryotic cells: cells with a nucleus (ex: plants,
animals)
- Prokaryotic cells: cells that lack a true nucleus (ex:
bacteria)
Made primarily of nucleic acids, proteins, and enzymes.
Surrounded by a double layer membrane that regulates
movement into and out of the nucleus.
Contains genetic code that gives the organism the
characteristics its possesses.
This genetic code is contained in a substance called
DNA (deoxyribonucleic acid).
The molecules of DNA are arranged in threadlike
strands called chromosomes.
Segments of chromosomes are called genes and are
responsible for transferring genetic codes.
*We will study this further in the reproductive
system.*
Small structures within
cytoplasm that serve different
roles.
Mitochondria: “powerhouse of the cell”. Breaks
down food nutrients and supplies the cell with its
energy. Cells that use more E (ex. Muscle cells)
contain more mitochondria than cells that are less
active (ex. Bone cells).
Vacuoles: serve as the storage compartments for the
cell. They consist of a membrane that encloses
water and other materials. They store nutrients and
enzymes needed by cells. They provide a storage
space for waste materials given off by the cell.
Microtubules: Found in animal cells, these
organelles are shaped like thin, hollow tubes
that are composed of proteins and act as the
“bones” of the cell. These support the cell,
give it shape, and assist in the movement of
chromosomes during cell division.
Microfilaments: Fine, fiber-like structures
composed of proteins that help the cell to
move by waving back and forth.
Ribosomes: Protein builders of the cell.
Golgi bodies or Golgi apparatus: Shaped like a
group of flat sacs bundled together. They
remove water from proteins and prepare them
for export from the cell.
Endoplasmic reticulum: large webbing or
network of double membranes throughout the
cell that transport material within a cell. Smooth
endoplasmic reticulum looks like tubes, while
rough endoplasmic reticulum has ribosomes
attached and looks like sheets of membranes.
Lysosomes: digestive units of the cell. They digest
proteins, carbohydrates, and other molecules. Any
foreign materials such as bacteria that enter the cell
are digested in the lysosomes.
Centriole:set of microtubules found in pairs near the
nucleus.
Complete the Basic Cell Biology Worksheet for a grade! Be
sure your name is on it and handed in completed sheet (front
& back) when done!
All growth that takes place in living organisms results from
cells increasing in size or numbers.
Cells have a very limited size to which they grow, so most
growth results from cells reproducing or multiplying.
When injuries occur to either plants or animals, cells
reproduce to heal the wound.
When a cell grows, it reaches a maximum size. When this
size is reached (parent cell), the cell divides into 2 cells
(daughter cells).
This process is called mitosis. The genetic coding in the
nucleus is duplicated and transferred to the new cells.
Period when cell is not actively dividing. It synthesizes
materials and moves them in and out of the cell. It is a period
of cell growth. When cell is correct size, the chromosomes are
duplicated and becomes ready to divide.
First stage of mitosis. Centrioles move to opposite ends of
the nucleus and mitotic spindles of thread begin to appear.
Chromatids move toward the center of the spindle (called the
equator). When they reach the center, the centromere of the
chromatids connect to fibers of the spindle.
Third stage of mitosis. The pairs of chromatids separate into
an equal number of chromosomes, and the centromeres
duplicate. When separation occurs, the chromosomes move to
opposite ends of the cell.
Final stage of mitosis. Remains of the spindle begin to
disappear, and new membranes form around the
chromosomes. This forms two new nuclei.
- Mitosis v Meiosis Web Quest
- Meiosis Web Quest
- Meiosis Study Guide
***Be sure all research
assignments are completed and
handed in for credit!***