surgical a&p for surgical technologists frey and price
TRANSCRIPT
Chemistry, Cellular Structure, and
FunctionSurgical A&P for Surgical Technologists
Frey and Price
Describe the basic concepts of chemistry Compare and contrast the structures and
functions of the cell Evaluate the importance of cell movement
and responsiveness Compare and contrast the elements of cell
reproduction Compare and contrast glycolysis and the
Krebs cycle
Objectives
Surgical technologists deal with tissue and organs on a daily basis.
The foundation for tissues is cells. We have to understand cells so that we
understand sterility (the destruction of certain cells)
Surgical technologists come into contact with cancerous cells on a near daily basis
Refer to case study 1 p. 17
Why do we have to study chemistry?
Anything that takes up space and has mass
Weight and mass are different.◦ Weight represents the gravitational pull on an
object◦ Objects in space still have mass even though they
are weightless
Matter
All matter is made of atoms
Different matter is made of different types of atoms
Matter constantly changes, physical states can change, but it will retain fundamental characteristics◦ Water in solid form is ice, liquid is water, and gas
is steam
Matter, cont’d
Energy causes change in matter Light, electricity, sound, heat, and
mechanical energy Mechanical energy makes objects move or
change course Objects can store energy as “potential
energy” Kinetic energy is the energy of motion
◦ Total mechanic energy is the sum of potential and kinetic energy
Energy
Made of subatomic particles◦ Protons are positively charged◦ Electrons are negatively charged◦ Neutrons are neutral
Atoms
Atomic mass is the mass of the protons and neutrons that make up the nucleus
Atomic number is the number of protons in the nucleus
An isotope is two elements that have the same number of electrons, but different number of neutrons. The difference in the number of neutrons changes the atomic mass, but the atomic number is still the same.
Electrons orbit around the nucleus like the planets orbit the sun◦ Valence electrons are in the outermost orbit
Atoms, cont’d
Each energy level can only hold a certain number of electrons◦ 1st level has the capacity for only 2 electrons◦ 2nd-4th level can hold up to 8 electrons
The valence (outermost) electrons determine how atoms behave
Ionization is the gain or loss of an electron◦ Positive ions LOST an electron (remember, electrons
have a negative charge◦ Negative ions GAINED an electron
Electrons
Elements are made of only one type of atom◦ Oxygen is made only of oxygen atoms◦ Hydrogen is made only of hydrogen atoms
COHN- 96% of living things are made from Carbon, Oxygen, Hydrogen and Nitrogen
Elements
Can be broken down into smaller substances
Represented by formulas
◦ For example: water is a compound made of two hydrogen atoms and one oxygen. The formula is H2O
Compounds
Atoms joined by chemical bonds
Molecular weight is the sum of the atomic weights
Molecules
Inorganic compounds do not contain carbon◦ Salts, CO2, water, acids and bases
Organic compounds contain carbon-hydrogen bonds◦ Proteins, fats and carbohydrates
Inorganic vs. Organic
A charged atom (one that has given up or taken an electron) is called an ion
A compound that dissociates (breaks apart) in water and forms positive and negative ions is an electrolyte◦ Salt in water is an electrolyte because the salt
breaks apart and forms sodium and chlorine ions
Ions and Electrolytes
Acids are substances that increase the number of H+ ions in a solution
Bases decrease the number of H+ ions in a solution
Acids and Bases
The scale ranges from 0-14
7 is neutral
0-6.9 is an acid; the closer to 0, the stronger the acid
7.1-14 is a base; the closer to 14, the stronger the base
Blood must remain in very strict limits; 7.35-7.45
pH Scale
The smallest living unit of the human body
Cancer is a cell that malfunctions and reproduces itself
Cells
1. All known living things are made of cells
2. The cell is the structural and functional unit of all living things
3. All cells come from preexisting cells by division (no spontaneous generation)
4. Cells contain hereditary info, which is passed from cell to cell
Cell Theory
5. All cells are basically the same in chemical composition. (Same types of organelles)
6. All energy flow of life occurs within cells.
Cell Theory, cont’d
Animal cells posses specific structures
Cells may vary by shape, location, and function
Cell Strucutre
Cells are not always perfect spheres. The shape can be controlled by substances outside the cell, or the contents of the cell.
Some cells will maintain their shape, others will vary
The mass of organs is due to the number of cells, not the volume of the cells
Cell Size and Shape
All cells contain:◦ Carbohydrates
◦ Proteins
◦ Lipids (fats)
◦ Nucleic acids
Cell Composition
Aka sugars
Carbon, hydrogen and oxygen form long chains to make carbohydrates
Monosaccharide-single sugar Disaccharide- double sugar Polysaccharide- many sugars
Carbohydrates
Made of amino acids attached to one another by peptide bonds
20 types of amino acids
Proteins
The fats
Fats are solid at room temperature, oils are liquid at room temperature
Lipids
RNA- ribonucleic acid
DNA- deoxyribonucleic acid
RNA and DNA are made of nucleotides
Each nucleotide has a nitrogenous base, a sugar and a phosphate
The nitrogenous bases are:◦ Adenine-thymine◦ Cytosine-guanine◦ Uracil replaces thymine in RNA
Nucleic Acids
The material that lies within the boundaries of the cell
Contains no genetic material
Contains the organelles
Cytoplasm
Surrounds the cell and separates the inside of the cell from the outside
Allows cells to interact with their surroundings if needed
Phospholipids and proteins compose the membrane◦ The phosphate end of the phospholipids love
water, the 3 fatty acid tails repel water
Cell (Cytoplasmic) Membrane
Keeps cytoplasm in
Osmosis is a process where water equilibrates on both sides of the cell membrane. The cell membrane is selective about what comes in and out. Nutrients in, waste out.
Functions of Cell Membrane
Some substances are too big or polar, and cannot cross the membrane. To allow the entry of certain substances, there are 4 transport systems◦ Passive diffusion◦ Facilitated diffusion◦ Group translocation◦ Active transport
Transportation through the membrane
Passive diffusion- no energy is required
Facilitated diffusion- no energy is required, a molecule binds to a specific protein in the cell membrane. It is selective.
Group Translocation- most requires energy. The target molecule is chemically changed as it enters the cell.
Active transport- pumps are used to move substances up the concentration gradient. Energy in the form of ATP is required.
Transport Processes
Largest structure within a cell. Eukaryotic cells are animal cells. They
possess a true nucleus surrounded by a nuclear membrane.
Prokaryotic cells are any cells not found in animals. They do not have a true nucleus.
Nucleus houses DNA See functions on pg 25
Nucleus
Endoplasmic reticulum is continuous with the membrane.
Nuclear envelope is similar to the cell membrane, but it surrounds the nucleus
The envelope has small holes that will allow a few substances to move into and out of the nucleus
Nuclear Membrane
Contains ribosomes, RNA, DNA, and proteins
rRNA is transcribed and processes and assembled into ribosomes
Ribosomes leave through the nucleus and they aid in protein synthesis
Nucleolus
Chromatin contains the genetic code and is stored in chromosomes
Two types of chromatin◦ Heterochromatin is condensed chromatin◦ Euchromatin is most abundant in active,
transcribing cells. The DNA must uncoil before the code can be read.
Chromatin and Chromosomes
Lysosomes Vacuoles mitochondria ER Golgi apparatus Ribosomes Centrioles Cilia Flagella
Organelles
Lysosomes digest waste materials and food
Vacuoles are areas of the cell membrane that fold inward and trap substances on the outside of the cell. It will pinch off and bring the molecule inside. (Think Pac-Man)
Endoplasmic reticulum (ER) transports substances. Rough ER is covered in ribosomes. Smooth ER is not.
Organelles
Mitochondria convert food into ATP. They are the major source of energy for the cell. Mitochondria have their own DNA. All mitochondria are derived from the mother. This is a very useful tool in forensics or identification.
The Golgi apparatus modifies and refines proteins and packages them in vesicles.
Organelles, cont’d
Ribosomes are the protein factories and can be free in the cytoplasm or attached to ER. The main function is to serve as mRNA translation.
Centrioles are rod-shaped and play a role in cell division
Cilia are shorter than flagella and function to move fluid or materials past an immobile cell. Millions of cilia line the respiratory tract to keep substances from entering the lungs.
Organelles, cont’d
Flagella are whip-like and propel a cell. The only flagellated cell in the human is sperm.
Organelles, cont’d
Some cells must be able to move throughout the body.
Cancer cells are very capable of movement.
Understanding how cancer cells move may lead to the advancement in fighting cancer.
Cell Movement
There are 46 chromosomes inside the nucleus and 1000’s of genes are contained on each chromosome.
The nucleic acids (RNA and DNA) contain our hereditary info.
DNA is the cookbook, RNA translates the cookbook
Nucleic Acids
Adenine pairs with Thymine◦ Forms two hydrogen bonds
Cytosine pairs with Guanine◦ Forms three hydrogen bonds
Base Pairing
DNA is a double helix structure
RNA is single stranded
DNA will “unzip” and a copy of one side will be made. This copy is called messenger RNA or mRNA.
Each 3 bases are called a triplet, and that is the specific code for one amino acid
DNA and RNA
Transfer RNA or tRNA lives in the cytoplasm. The tRNA picks up the appropriate amino acid
When all of the amino acids have been assembled and all of the peptide bonds have been formed, it is now a protein.
DNA and RNA
Before cells divide, the DNA must make a copy of itself.
The DNA will ‘unzip’ and one side serves as a template to make a complementary strand.
After complete division, each cell will have one old side and one new side.
DNA Replication
5 Stages◦ Prophase◦ Metaphase◦ Anaphase◦ Telophase◦ Interphase
Mitosis
Chromosome condense and distribute between the two cells
Centromere forms between two identical chromosomes
Microtubules from each side of the cell attach at the centromere.
Prophase
The chromosomes will line up in the middle of the cell
The microtubules will eventually pull the chromosomes apart.
Metaphase
The centromere is pulled apart.
One chromosome goes to one side, the other goes to the other side.
This equally divides DNA in the two cells
A cleavage furrow appears by late anaphase
Anaphase
Each chromatid is now a separate chromosome
New nuclear envelope starts to appear
Cell membrane will be completed for each cell.
Telophase
Used to be called “resting phase”, but there is no resting happening!!!
Organelles begin to form, nutrients are absorbed.
Interphase lasts until the next mitosis.
Interphase
Formation of gametes (sperm and ova)
Unlike mitosis, the cells divide twice in meiosis. Each resulting cell will have half of the genetic material (23 chromosomes)
In males, meiosis is spermatogenesis In females, oogenesis
Meiosis
Chromosomes become visible
Chromosomes have duplicated and become chromatids attached by a centromere
“crossing over” can occur
1st meiotic prophase
Chromosomes line up in the middle
1st meiotic metaphase
Chromosomes and chromatids will move to one end of the spindle
This results in each daughter cell only getting one copy
1st meiotic anaphase
Two daughter cells will appear
Nuclear membranes appear around the chromosomes
1st meiotic telophase
Chromosomes re-appear
Chromatids are joined by a centromere
2nd meiotic prophase
The chromosomes attach to spindle fibers
2nd meiotic metaphase
Centromeres separate
Chromatids move to opposite ends of the cell
2nd meiotic anaphase
The cell division is complete
Spermatogenesis results in the formation of 4 sperm cells with 23 chromosomes
Egg cells also contain 23 chromosomes
2nd meiotic telophase
Glycolysis and Kreb’s cycle
Cellular respiration is the process of oxidizing food molecules and turn them into carbon dioxide and water.
Glycolysis occurs in the cytoplasm, the Kreb’s cycle occurs in the mitochondria
Cellular Respiration
Aka anaerobic metabolism (no oxygen required)
Glyco= sugar Lysis= to break down
Glucose is broken down into pyruvate
Only 4 ATP particles can be made from one glucose
The pyruvate is taken to the mitochondria where it is converted to acetyl coenzyme A (acetyl coA)
Glycolysis
Aka aerobic oxidation, the citric acid cycle, or tricarboxylic acid cycle
Takes place in mitochondria
There are ten steps and the acetyl coA yeilds energy and CO2
Electrons are taken out of the food we eat to help produce ATP and other cellular functions
Kreb’s Cycle
Pyruvate enters mitochondria and CO2 is released. Acetyl coA is formed.
Acetyl coA joins a 4-carbon molecule called oxaloacetate to form citric acid
Citric acid is broken down and carbon and hydrogen ions are released.
The hydrogen ions are picked up NAD+ and FAD+ and ATP is released.
Kreb’s cont’d
CBC includes◦ White blood cell count◦ Red blood cell count◦ White blood cell types◦ Hematocrit◦ Hemoglobin◦ RBC indices◦ RBC distribution width◦ Platelet count◦ Blood smear
CBC
What is chemistry?
What is mass? Matter?
What are the subatomic particles?
What is atomic number? Atomic mass?
What is an element?
Summary
What is a compound?
What distinguishes an organic compound?
What is an ion?
What is the pH scale? What values are given to acids? Bases?
Summary
What are the 4 primary organic molecules?
What are proteins made of?
What are the organelles?
What are the four types of transport systems?
What are the nucleic acids?
Summary
What is mitosis?◦ What are the stages?
What is meiosis?◦ What are stages?
Summary