Download Chapter 3 Study Guide: Cells

Chapter 3 Study Guide: Cells, Cancer Biology, Tissues, and Wound Healing
TEST is WEDNESDAY OCTOBER 22, 2014 Q&A on TUESDAY
Look over all prior quizzes
What is a cell? Are all cells the same? How can we categorize cells?
 A cell is the smallest living unit of structure and function for humans.
 Not all cells are the same; size, shape, location, and organelle composition determine what the cell
will do for a function and determine the longevity/life span of the cell.
 Cells can be categorized according to location in the body and ability to undergo mitosis (labile,
stabile, permanent).
What are the important functions of the cell membrane? Be specific.
 Separates cells from their surrounding environments.
 Selectively permeable; limiting what exits and enters the cell.
 Proteins act as channels to allow passage of large particles and water-soluble molecules.
 Carbohydrates act as cell surface markers to identify specific cells; self vs. nonself.
Describe the phospholipid bilayer and how its structural components (hydrophilic/hydrophobic) allow it to
function as a barrier.
 Cell membrane is composed of HYDROPHILIC heads that “like water” and make up the outermost
and innermost parts of the phospholipid membrane due to the water content of the extracellular
space and cytosol within the cytoplasm.
 The inner portions of the cell membrane are HYDROPHOBIC fatty acid tails; facing toward each
other due to their “water fearing” composition. This portion of the cell membrane is what limits
the passage of water through diffusion. Water must move through a protein channel (aquapore)
by facilitated diffusion.
What word do we use to describe the transport property of the cell membrane? Why?
 SEMIPERMEABLE- this is the “gatekeeper” quality of the cell membrane, limiting the movement of
molecules. A loss of membrane control is what leads to disease/disorders. The more control is
lost - the more abnormality in the cell – the more disease/disorder.
What are the functions of membrane proteins? Carbohydrates/Glycocalyx? Cholesterol?
 Proteins act as channels
 Glycocalyx and Carbs act as cell surface identifiers
 Cholesterol acts to stabilize the cell membrane and make it more rigid to maintain structure.
What is contained in the nucleus? Why is the nucleus important?
The nucleus contains chromatin – long thin strands of DNA that contain info needed to make structural
components for the cell and perform cell functions. The nucleus offers an additional membrane barrier to
protect the DNA from mutations.
Know the functions of the following organelles:
Ribosomes: assemble amino acid sequences into proteins.
Lysosomes: digest foreign particles to remove from cell interior or extracellular space.
Nucleus: contains and protects DNA in cell interior.
Mitochondria: creates energy (ATP) from glucose and oxygen = cell respiration.
Know Cell Clock information and what happens in each phase.
 G1: growth and work
 G0: quiescence- cells work but do not divide. Determined by cell type
o Labile cells never quiesce; they are constantly in the cell clock ready to divide: Skin
o Stabile cells enter quiescence after growth is completed; will divide if injured: Bone
o Permanent cells enter quiescence after growth and will never divide again: Brain
 S: synthesis/copy DNA for mitosis
 G2: growth and work
 M: mitosis/nuclear division usually followed by cytokinesis (division of cytoplasm, organelles, and
cell membrane) leading to the creation of 2 new cells that will enter G1.
CANCER BIOLOGY
What is the relationship between MITOSIS and CANCER? How is the cell clock of cancer different than a
normal cell clock?
The cell clock of a normal cell and a cancer cell are essentially the same; the main difference is the amount
of time each type of cell spends in different phases of the cell clock. Normal cells spend most of their time
in INTERPHASE (G1, S, G2) and little time in MITOSIS (M). Cancer cells spend most of their time in MITOSIS
(M) and little time in INTERPHASE (G1, S, G2).
What is cancer? What is benign? Malignant?
 Cancer is uncontrolled cell division (mitosis and cytokinesis)
 Benign growths result from uncontrolled cell division; tumors have abnormal STRUCTURE but
normal FUNCTION.
 Malignant growths also result from uncontrolled cell division but have abnormal STRUCTURE and
FUNCTION.
 Metastasis: the ability of cells to break free from malignant growths, travel through the blood
stream, and create a secondary tumor in a different location in the body.
Explain the factors that influence the formation of cancer in the body.
 Hereditary:
o Genetic predisposition for “bad mitosis” can result in cancer of any tissue.
o Inheritance of specific cancer-causing genes, for example BRCA-1 gene for breast cancer,
can increase your chance of THAT specific cancer.
 Environmental:
o Risk factors such as smoking, diet, pollution, sun exposure can increase the chance of
certain types of cancer.
Describe proto-oncogenes, tumor suppressor genes, and oncogenes.
 Proto-oncogenes control NORMAL cell division; without PO our cells would not be able to grow
and divide. Think of PO as the gas pedal promoting cell division.
 Tumor Suppressor Genes control the RATE of cell division; without TSG our cells would divide
uncontrollably from the start.
o It is the balance of PO and TSG that promotes NORMAL CELL GROWTH AND DIVISON.
 Oncogenes are mutated PO’s that now divide at an uncontrolled rate. Genetic and Environmental
factors cause the mutations that lead to cancer development.
How do we diagnose and treat cancer? Are all cancers the same?
TMN System of Diagnosis
T= Tumor Size and Location
M= Metastasis – has the cancer spread to other areas?
N= Lymph Node involvement is another clue to metastasis.
Not all cancers are the same. By grading the tumor with the TMN system and discovering the genetic
cause of each person’s specific type of cancer doctors can provided targeted therapy to destroy cancer
cells and leave healthy, labile cells alone. This helps the patient have a better quality of life during
treatment and recovery.
Cut, Burn, Poison = Surgery, Radiation, and Chemotherapy
What are the four main tissue types in the body? Functions?
 Epithelial tissue lines internal and external body cavities for protection and secretion of products.
 Connective tissue connects epithelial membranes to underlying tissues or connects internal
structures together. This is the MOST diverse group; blood, bone, cartilage are examples.
 Muscle tissue is designed to create movement. There are 3 types of muscle tissue: smooth,
skeletal, and cardiac. Muscle tissue is categorized by control (voluntary vs involuntary) and the
organization of cells (striated vs nonstriated).
 Nervous tissue is designed to conduct an electrical current; found in the brain and spinal cord.
Understand wound healing, tissue regeneration, and inflammation. KNOW YOUR MEDIATORS OF
INFLAMMATION!
 Tissue regeneration is determined by 2 factors:
o Severity of wound: how bad is the injury
o Type of tissue damaged: labile, stabile, permanent
 3 steps in wound healing
o Capillaries become permeable, allowing needed nutrients to leave bloodstream and enter
injured tissue; Scab forms.
o Granulation tissue forms to support blood flow to injured area; phagocytes (“eating” white
blood cells) keep area free of debris and infection.
o Surface epithelium regenerates from the bottom up; a scar forms if needed to bridge the
gap.
 4 cardinal signs of inflammation and their chemical control
o Redness: CHEMOTAXIC AGENTS allow for increased blood flow to the area, bringing
needed materials for wound healing. More blood = more color (redness).
o Heat: PYROGENS increase the local temperature destroying the proteins that allow
pathogens to infect the area.
o Swelling: HISTAMINE causes leaky capillaries, allowing plasma to leave the bloodstream
and enter the tissue space bringing needed nutrients and white blood cells to the damaged
tissue. The more plasma (water) the more it swells.
o Pain: PROSTAGLANDINS are part of the “pain pathway” and initiates activation of pain
receptors in the damaged tissue.
Remember, ACUTE inflammation has a positive impact on the healing process. Short term
inflammation is a necessary part of healing a wound or injury. Without inflammation we do not
have the ability to get the materials damaged tissue needs to the area that is injured. CHRONIC
inflammation, lasting longer than 2 weeks can cause more damage than good and needs to be
addressed.