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Chapter

BISC 101 Chapter Notes -Golgi Apparatus, Drug Detoxification, Regional Policy Of The European Union


Department
Biological Sciences
Course Code
BISC 101
Professor
Derek Bingham

Page:
of 4
Structure and Function of Cells
Objective 1 – Specify the characteristics we associate with life and explain why
the cell is considered to be the basic unit of life:
1. Exchange materials with the environment. Some are taken in, some are released. Cells take in
nutrients and nutrient gases, and expel wastes on an ongoing basis. Our cells absorb needed materials
from, and deposit waste materials into, the ECF.
2. Obtains energy from organic materials. Cells take in sugars and metabolize them to obtain energy
which can then be used to perform cellular activities.
3. Can synthesize complex organic molecules. Proteins and fats are only found in living cells or
organisms, or in situations where living cells have deposited the molecules.
4. Reproduction
5. Can respond to environmental stimuli. Cells and organisms respond to cold temperatures by moving
somewhere warmer, or by altering their physiology to make more heat.
The cell is the basic unit of live because a cell is the simplest structure that processes all the basic components of
living matter. These processes are assigned to living cells, not the whole organism.
Objective 2 – Describe the chemical, cellular, tissue, and organ system levels of
structural organization in the body.
Cells are the basic structural/functional units of the body. Composed of chemical substances, organelles, and
membranes that are necessary for life. They do not exist independently of each other.
Chemicals are organic and inorganic molecules.
Tissues are organized groups of cells that carry out specific functions. A tissue is a group of similar cells and their
associated intercellular materials, which have similar origins and functions. They also have a similar appearance.
Tissues are then organized into organs: a structure with a definite form and function composed of 2+ tissue types.
Organs are then arranged into systems that are consisted of organs that interact to perform a specific function.
These systems then comprise the whole body.
Objective 3 – Describe the structure (identify them in a diagram!) and describe
the functions of the following cytoplasmic components:
Cell (Plasma) Membrane:
Surrounds the cell
Regulates what materials enter and leave the cell
Allows communication with the extracellular environment
Endoplasmic Reticulum:
Series of interconnected tubes/membranes that extend throughout cytoplasm
o Rough ER membranes studded with ribosomes; a transport system that processes and sorts
proteins for export to the Golgi complex; produces some distinct groups of proteins
o Smooth ER – a continuation of the rough ER without ribosomes; lipid synthesis, metabolism,
transport; sex steroid hormone synthesis in certain cells; drug detoxification
Ribosomes:
The site where info from DNA is used to make proteins
Two types of ribosomes:
o Free ribosomes – float in the cytoplasm
Produces proteins used immediately in the cytosol (ICF) of the cell
o Attached (“bound” or “fixed”) ribosomes – produces 3 groups of proteins:
Proteins to be exported out of the cell
Cell membrane proteins
Proteins for inside membranous organelles
Golgi Apparatus:
Stack of flattened membranous sacs
Takes the proteins made by bound ribosomes and modifies, concentrates, packages, and ships them to
their final destinations:
o Outside the cell
o In the cell membrane
o Inside membrane-bound organelles
Lysosomes:
Small sacs bound by one membrane
Carries enzymes that digest different types of organic molecules inside cells
Breakdown of bacteria, viruses, and toxins brought into the cell by phagocytosis
Breakdown of old organelles
Activates release of stored molecules
Autolysis – the self-destruction of injured or dying cells
Mitochondria:
Generally bean-shaped
Surrounded by double membranes with the inner one being very folded
Sites of cellular respiration – a process that breaks down glucose and produces adenosine triphosphate
(ATP) for the cell’s energy source
May be from 100 to several thousand per cell
Vesicles (Vacuoles):
Membrane bound sacs that contain food particles, solids, or liquids
Stores, imports, and exports materials
Objective 4 – Describe the structure and describe the functions of the following
nuclear components:
Nucleus contains the DNA, which has the info required to make proteins
By determining which proteins to make, the nucleus regulates all cellular activities
Most cells have ONE nucleus although larger cells (i.e., skeletal muscle cells) may have several. RBC’s
don’t have a nucleus
1. Nuclear envelope – double membrane with pores that regulate passage of material in and out of the
nucleus
2. Chromosomes when a cell prepares to divide, the chromatin in the nucleus coils and condenses to form
short rod-like structures called chromosomes. These carry genes that transmit genetic info from one
generation to the next.
3. Nucleolus – one or two darker regions within the nucleus that produce the basic subunits of ribosomes;
ribosomal subunits are transferred to the cytoplasm where they are assembled there.