Basic Cell

1
Basic Cell
Biology
2

• 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.

3
Cell Membrane

• 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.

4

• 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.

5
Cytoplasm

• 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.
• Its what gives the one-celled organisms, like
  amoeba, its ability to move.

6
The Nucleus

• 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.

7

• 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.

8
Organelles
Small structures within cytoplasm that serve
different roles.
9
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.
10
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.
11
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.
12
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. Centrioleset of microtubules found
in pairs near the nucleus.
Research Assignment
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!
13
Cell Reproduction

• 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.

14
Stages of Mitosis
Interphase
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.
Prophase
First stage of mitosis. Centrioles move to
opposite ends of the nucleus and mitotic spindles
of thread begin to appear.
15
Metaphase
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.
Anaphase
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.
Telophase
Final stage of mitosis. Remains of the spindle
begin to disappear, and new membranes form around
the chromosomes. This forms two new nuclei.
16
Mitosis v. Meiosis

• Mitosis v Meiosis Web Quest
• Meiosis Web Quest
• Meiosis Study Guide
• Be sure all research assignments are completed
  and handed in for credit!