Flashcards in A&P Chapters 3-4 Cellular Form/Function, Genetics Deck (97):
Describe the 5 Components of Modern Cell Theory
1. All organisms are composed of cells and the products of those cells
2. The cell is the simplest structural and functional unit of life
3. An organism’s structure and function is due to the characteristics of its component cells
4. Cells are only derived from other cells
5. Since all cells in an organism share a common ancestry, they all share some similarity in composition and metabolism
Everything in the body is a cell or made from a cell.
What is the common size of a cell? Why is it important that the cell not get too large?
The typical size of a cell is 10-15 microns.
It is important that a cell not get too large because it cannot coordinate the exchange of nutrients and waste properly. The cell cannot diffuse nutrients and waste out quickly enough.
What are the 3 components that 99.9% of cells have?
Cell Membrane, Organelles, Cytoplasm
Describe the cell membrane
Completely envolopes the cell and regulates what comes in and what goes out of the cell.
The cell membrane is made of a phospholipid bilayer with many proteins, glycoproteins, glycolipids and other structures embedded in the membrane.
The cell membrane is a double layer of phospholipids, the phospholipid bilayer. 98% of the membrane is phospholipid.
The heads of the phospholipids are hydrophilic, they are polar and contain a phosphate group. They face the extracellular and intracellular side.
The hydrophobic fatty acid tails are buried in the middle of the membrane.
The other 2% of the membrane is a variety of protiens and other structures. These protiens regulate the movement of molecules across the membrane.
Many biological molecules are not able to pass freely across the membrane. They need protieins to transport them.
The intracellular environment consisting of cytosol and cytoskeleton.
Why is cytoskeleton important?
It gives and manages the shape of a cell. The cytoskeleton also provides for the transportation of materials in a cell.
Organelles do what?
Carry out specialized tasks and metabolic processes.
List some membrane protiens
Receptors, Enzymes, Channel Proteins, Cell Identity Proteins, Cell-adhesion molecule.
Bind to chemical messengers such as hormones sent by other cells.
Break down a chemical messenger and terminates it's effect.
Ion Channel Proteins...
Are constantly open and allow ions to pass into and out of the cell.
Gated Ion Channel Proteins...
Open and closes to allow ions through only a certain times.
Are glycoproteins acting as a cell identity marker distinguishing the body's own cells from foreign cells.
Bind one cell to another.
The diffusion of water down its concentration gradient. Water moves to the side of the membrane with the higher solute concentration to reach equilibrium.
Water is free to move across cell membranes and will move from an area of LOW solute concentration to an area of HIGH solute concentration.
What can pass freely through cell membranes? What cannot?
Water, Oxygen, CO2, steroids and some small uncharged molecules can pass freely.
Proteins, fatty acids, large molecules and ions cannot pass freely across the membrane.
The process in which a red blood cell in a hypertonic solution becomes shrunken and spiky.
The destruction of a cell, when it gains too much water and bursts.
A solution is a combination of...
A solvent: in biology it is typically water.
A solute: in biology they are often ions, proteins, and hormones.
When concentration of solute is greater outside than inside. Ex: A hypertonic solution has a HIGHER concentration of a solute than what is found inside the cell.
The 5% NaCl solution will draw water out of the cell and into the area around the cell thus crenating the cell.
When concentration of solute is the same inside and out.
When concentration of solute is lower outside THAN INSIDE. Ex: The hypotonic solution has a LOWER concentration of a solute than what is found inside the cell.
The 0% NaCl solution has more NaCl inside the cell (0.9%) and so water moves into the cell to dilute the NaCl in the cell to that of the concentration outside of the cell.
What is the rule about solute movement across a cell membrane?
Solutes move from high concentration to low concentration.
What are the two types of Carrier-Mediated transport? What is transported?
Facilitated Diffusion and Active Transport
Solutes (ions, proteins, ect..) are transported. Things that cannot otherwise diffuse freely across the cell membrane.
Transporters are membrane proteins and are very specific about what solutes they can transport.
Describe Facilitated Diffusion
A situation in which a solute travels across the cell membrane DOWN ITS CONCENTRATION GRADIENT.
The solute travels across the plasma membrane using a membrane protein but does NOT REQUIRE ATP, this occurs as long as the concentration is unequal on each side of the plasma membrane.
Describe Active Transport
A situation when a solute travels AGAINST ITS CONCENTRATION GRADIENT.
This process USES ATP and creates or maintains a concentration gradient where solute concentrations are higher on one side of the membrane.
The Na/K ATPase is an example of what?
Active Transport: Very important for maintaining cell ion concentrations and cell volume.
Na/K ATPase is a very important Enzyme.
Define a Uniporter
Moves One solute in One direction.
Define a Symporter
Moves Two solutes in One direction
Define an Antiporter
Moves Two solutes in Two directions
Na/K ATPase is an Antiporter
What is Vesicular Transport ideal for?
Transporting very large molecules, large numbers of molecules, and liquids.
This is how glands release hormones into the bloodstream.
Bubble like structures made up of pieces of the plasma membrane.
The process by which particles or liquid are brought INTO the cell.
Involves the formation of a pit, invagination of the PM and pinching off and separation of the vesicle from the PM.
The process that sends particles or liquids OUT of the cell.
The reverse of endocytosis.
What are the types of Endocytosis?
Phagocytosis, Pinocytosis and Receptor-Mediated Endocytosis
What Types of Cells Employ Phagocytosis?
The "cell eating" process by which a cell engulfs particles or debris. Only a few cells in the body use this process.
Immune System Cells, White Blood Cells
Process by which a cell takes in droplets of liquid containing solutes. This process is non-specific because the cell brings in whatever particles are found in the fluid, this can be a disadvantage.
Virtually every cell in the body employs this process.
Describe Receptor-Mediated Endocytosis
Uses a plasma membrane protein to selectivly collect specific solutes in specific quantities and bring them inside the plasma membrane. This involves the use of receptors on the outer surface of the plasma membrane. Many growth factors and hormones enter the cell this way.
The process in more detail: Begins with extracellular solutes binding to receptors on the surface causing the receptors to cluster together.
Clustering causes the plasma membrane to invaginate around receptors forming a pit.
Invagination continues until the newly formed vesicle pinches off from the plasma membrane and is released into the cytoplasm of the cell.
A chemical that binds reversibly to a receptor site on a protein, such as a neurotransmitter that binds to a membrane receptor or a substrate that binds to an enzyme.
What is the most important carbohydrate monomer?
Describe the differences between the three polysaccharides.
Cellulose: We can't use for energy production, just dietary fiber for digestive tract health.
Starch: Main source of digestable carbohydrates.
Glycogen: The stores held inside the body primarily in the liver but also in skeletal muscle.
Where is DNA found?
The nucleus of a cell.
DNA is ultimatly used to make what?
Which base pairs match together to form DNA/RNA?
Adenine and Thyamine, Guanine and Cytosine
Adenine and Uracil, Guanine and Cytosine
What is a gene?
A specific segment of DNA that contains the information to sythesize a protein.
What lipid plays a special role with injured/damaged tissues?
Eicosanoids play an important role in inflammation, cell signaling and blood clotting.
What are some examples of steroids found in the body?
Testosterone, Estrogen, Cortisol (Hormones)
Dehydration synthesis is required for what biological activity?
What does the word Denatured refer to?
When a protein loses it's conformation (3D shape)/normal structure.
What are the six organelles?
Nucleus, Endoplasmic Reticulum, Ribosomes (Bound to E.R.), Golgi Apparatus, Lysozomes/Peroxisomes, Mitochondria
Describe the Nucleus
Largest of the Organells, Usually spherical in shape.
Surrounded by a Nuclear envelope that consists of a DOUBLE phospholipid bilayer.
Contains nuclear pores that allow the transcription factors and RNA molecules in/out.
Also contains CHROMATIN which is coiled up DNA strands.
Describe the Endoplasmic Reticulum
The ER is a series of networks adjacent and continuous with the outer phospholipid bilayer of the Nuclear Envelope.
There are two types of ER, the ROUGH ER is dotted with ribosmes for protein synthesis. Proteins are sythesized in the Ribosomes on the surface of the ER then proceeds to get their conformation in the ER with hydrogen bonds.
The SMOOTH ER has no ribosomes.
The ER plays an important role in the sythesis of steroids and lipids, it also has enzymes (P450) that are responsible for the detoxification of drugs and alcohol. Note: Most cells only have a SMALL amount of SMOOTH ER but in alcholoics/drug users the ER proliferates to keep up with the detoxification lending to drug tolerence.
Found in the nucleolus, ROUGH ER, and in the cytoplasm.
Ribosomes are complexes of protein and RNA, they function to translate RNA messages into proteins.
Membrane bound vesicles that contain LYSOZOMAL enzymes.
LYSOZOMAL enzymes hydrolyze (break down) fats, proteins, DNA/RNA and carbohydrates.
Lysozomes are also important in breaking down bacteria, viruses, and damaged cells that have all been phagocytosed. FOUND IN WBC'S!!
Lysozomes also breakdown and recycle non-vital organelles and other cell components as well as Autolysis of surplus cells. Ex. the shrinking of a 900g uterus at full term to 60g within 5-6 weeks after birth.
Similar to lysozomes but they contain oxidative enzymes that produce and utilize H202 (Hydrogen Peroxide) to metabolize organic compounds.
Describe the Golgi Apparatus
A system of sacs often found near the ROUGH ER.
The Golgi Apparatus systhesizes carbohydrates and add sugars to glycoproteins.
The Golgi recieves newly made proteins from the ROUGH ER, these proteins do not yet have the 3D shape they need, the Golgi modifies them, sorts them and packages them into Golgi Vesicles for transport to other parts of the cell.
The Golgi acts like the cells post office.
Decribe the Mitochondria
The "Powerhouse" of the cell, responsible for the production of ATP.
Has an inner and outer membrane, the inner membrane is where ATP is synthesized.
Also contains it's own DNA called mitochondrial DNA, this allows Mitochondria to make their own proteins and enzymes.
Many of the reactions that occur in the Mitochondria are oxidative (Redox) reactions. Damage to the mitochondria leads to the release of oxygen free radicals into the cell which can cause cell and tissue death. Alzheimers, Parkinsons and some cardiovascular diseases are linked to oxidative stress from mitochondrial damage.
Describe the Cytoskeleton and What are the three types of filaments?
The collection of protein filaments that supply structural support and transport within the cell. Contains three types of filaments.
Microfilaments, Intermediate Filaments, Microtubules.
What do the Microfilaments of the Cytoskeleton do?
They are the smallest of the filaments and they form the meshwork that supports the phospholipid bilayer giving it a structure to rest upon.
Describe the Intermediate Filaments of the Cytoskeleton
The Mid-sized filaments that supply rigidity to the cell.
Describe the Microtubules of the Cytoskeleton
The largest filaments of the cytoskeleton that are important in cell division. These filaments hold the various organelles in their proper position, they also form the highway or railroad that is used to transport things from one region to another inside the cell.
What is a Codon?
A series of 3 nucleotides that encodes an amino acid.
Many amino acids are encoded by more than one codon.
Some codons don't encode amino acids instead they tell ribosomes where a gene starts and where it ends.
Start condon: AUG Methionine
Stop codons: UAA, UAG, UGA.
How many chromosomes do you have?
46, 23 from your mother, 23 from your father.
There are 22 pairs of AUTOSOMES and one pair of SEX CHROMOSOMES, XX = Female and XY = Male
What is the law of complimentary base paring?
The fact that one side of a DNA molecule governs the base sequence of the other side.
What is the protein that carries out RNA sythesis?
RNA Polymerase, it "reads" the DNA and makes an RNA copy called mRNA (Messenger) The mRNA is sent out of the nucleus and used by some ribosomes to make specific proteins.
Translation is (More Involved Answer This Time)
Process by which the genetic information encoded in mRNA is used to sythesize proteins.
Converts the language of nucleotides into the language of amino acids.
What are the major players involved in translation?
mRNA, Ribosome, tRNA
mRNA is formed when RNA Polymerase "reads" DNA, the mRNA has the corresponding base pairs to the side of DNA copied.
With reference to Translation what do Ribosomes do?
They coordinate the assembly of peptide bonds needed.
Explain tRNA and it's function in Translation
It is a specialized RNA molecule that holds an amino acid on one end, it binds to the codons of mRNA with the opposite end with an ANTICODON
Explain DNA Replication
The original DNA molecule unwinds from it's double helix structure.
DNA Polymerase binds to each of the exposed strands and "reads" the DNA, then free nucleotides are used to make a new complementary strand.
The result is two stands of DNA each with a new strand formed from the free nucleotides and a strand from the original unwound strand of DNA.
What are the types of Genetic Mutations?
Point Mutations and Insertions/Deletions
Explain Point Mutations
Simple replacement of one nucleotide for another. Comes in three forms.
Silent Point Mutations: the change in nucleotide doesn't change the amino acid sequence of a protein, remembering the reduncancy of the Genetic Code it may simply form a codon that would have created the same Amino Acid or the mutation occurs in the junk DNA and has no effect.
Missense Mutations: A change in the nucleotide leads to change in the Amino Acid sequence of protein.
Nonsense Mutations: A change leads to the formation of a STOP codon forming a shortened protein.
The Addition or Removal of a Nucleotide, this can alter how a ribosome reads the mRNA which leads to a mutant protein.
This SHORTENS or LENGTHENS the genetic code for a particular protein.
What are the classifications of Genetic Mutations?
Gain of Function and Loss of Function
Gain of Function refers to a situation where a mutation leads to a protein with a new function or activity.
Loss of Function refers to a situation where a mutation causes a protein to be non-functional.
Some mutations are good, some bad and some are both good and bad.
Define the Cell Cycle
Process by which ONE parent cell grows and replicates all of its component structures (Plasma Membrane, Organelles, ect...), it undergoes division and yields TWO daughter cells.
What are the two types of cell division?
Mitosis and Meiosis
Mitosis is the normal cell division where one cell divides to produce TWO genetically identical cells, almost all cells in our body divide this way.
The special cell division used to produce gametes (sperm and eggs). Each cell produced contains HALF the normal amount of genetic material.
What is a Gamete?
A Sperm or Egg Cell, each contains HALF the normal amount of genetic material. 23 Chromosomes each to combine forming a single cell with 46 Chromosomes.
What regulates the timing of the cell cycle?
Cell Conditions, Growth Factors, and Environmental Conditions.
When both copies of a gene are mutated.
Remember you have 23 PAIRS of chromosomes, which means you have TWO copies of every gene.
In the Hemoglobin gene, homozygous will result in sickle cell anemia.
When only one copy of a gene are mutated and the other copy remains unmutated.
In the Hemoglobin gene example this produces a resitance to malaria but only mild sickle cell anemia symptoms.
What are Alleles?
The technical term for the two copies of the genes each cell carries.
What is the mistake rate for DNA Polymerase? How does the cell manage these mistakes?
1 in 1 Million, to manage the mistakes additional enzymes specifically other polymerases proof read the DNA strands.
Give an example of celsl that divide rapidly. What about those that divide slowly or not at all?
Epithelial Cells and Cells that line our digestive organs are replaced frequently.
Brain cells, Muscle cells (especially Cardiac), Bone and Nerve cells are either static and divide very slowly or not at all.
What are the phases of of Mitosis? What is the rule about the phases of Mitosis?
Interphase and the Mitotic Phase
One phase of the cell cycle cannot progress until the previous phase is complete, this is called CELL CYCLE CHECKPOINTS
What is the Interphase of Mitosis?
The time that a cell is either doing what that cell is supposed to do or getting ready to divide.
Comes in three phases, G1, S, and G2 phases.
G1 is where most cells spend their time, doing the tasks they are meant to do.
Cells move to the S phase when they are supposed to start dividing. DNA replication occurs during this phase.
G2 phase occurs when the DNA replication is complete, it is growing and preparing for mitosis.
What is the Mitotic phase of Mitosis?
The time when the cell is actively dividing. Nuclear components are duplicated, DNA is divided up and the parent cell pinches off into two daughter cells.
What are the phases of Meiosis?
Interphase, Meiosis 1 and Meiosis 2.
What occurs during Meiosis 1?
The chromosomes duplicate and undergo CROSSOVER RECOMBINATION between chromosomes.
The CROSSOVER RECOMBINATION allows for genetic variability.
What occurs during Meiosis 2?
The daughter cells that just underwent CROSSOVER RECOMBINATION undergo another division without replication of DNA yielding 4 cells, each with HALF the normal complement of chromosomes, 23 individual chromosomes rather than 23 pairs.
What is Nondisjunction? What happens if the Gamete with this is used for reproduction?
When during Meiosis 2 chromosomes fail to properly segregate resulting in one daughter cell receiving 2 copies of a chromosome and the other receiving none.
The resulting offspring will end up with either 3 copies of a given chromosome or only one copy in all of their cells.
What is Trisomy?
When an embryo receives 3 copies of a given chromosome, often resulting in non-viability thus not surviving, some however do survive as in Downs or Edwards Syndrome.
What is Monosomy?
When an embryo receives only one copy of a given chromosome, this results in non-viability and do not survive.
Cells that have 23 PAIRS of chromosomes.