RAT #1 Flashcards
Covalent bond
1 Atoms share electrons
Strongest type of bond
Ex - Carbon atoms in glucose
Ionic bond
2 Opposite ions are attracted to each other i.e. NaCl
Hydrogen bonds
3 A weak attraction between a hydrogen atom and a nearby O, N, or F atom i.e. attraction between water molecules
Note - bonds that are within a water molecule are covalent
Van der Waals forces
4 Weakest type of attraction, non specific interaction between the nucleus of one atom and the electrons of another - allows molecules to pack close together.
“like dissolves like”
Ex - phospholipid molecules
Why is van der waals forces weak?
Because if the atoms get too close their electrons repel each other.
LO Define homeostasis
Body’s complex maintenance of ideal physical conditions. Ex: maintain blood pressure, blood pH, glucose levels
LO Describe a simple homeostasis loop
A controlled variable is monitored by a sensor, which reports to an integrating center (usually central nervous system). The integrating center processes info and sends out signals (usually via nerves or hormones) to the effector tissues to correct the problem.
Plasma membrane
A flexible barrier that holds cell shape.
Phospholipid bilayer with cholesterol molecules throughout
Proteins on the inside/outside surface that are important in recognition
Nucleus
DNA is transcribed into mRNA here, which is then translated into proteins in the cytosol.
Contains nucleolus that synthesizes proteins
Mitochondria
Powerhouse of the cell (most ATP is produced here)
Contains (co)enzymes important in the krebs cycle and electoral transport chain
Rough endoplasmic reticulum
Ribosomes cover this folded structure. Translation of mRNA to make proteins that will be exiting the cell take place here
Proteins translated by free Ribosomes will stay in the cell
Smooth endoplasmic reticulum
Steroid hormone and lipid synthesis (anabolism) and break down (catabolism), site of calcium storage and calcium release based on cell activity
Golgi apparatus
Folded membrane that is the “finishing school” for proteins that are to be exported out of the cell.
Membranous organelles include
Mitochondria and golgi
Which cell structures/functions involved microtubules
Cilia, moving molecules from one pt of the cell to another, flagella, mitosis
Which is not a membranous bound organelle made from insoluble protein fibers
Polyribosomes
Cells that secrete large amounts of protein would most likely possess larger numbers of or an extensive network of ______.
Ribosomes, golgi, RER
LO Leaky Junctions
Lots of traffic between cells ex between heptocytes (liver cells)
LO Tight Junctions
Junctions that restrict the movement of materials between the cells they link
Barrier properties of tight junctions are dynamic and can be altered depending on the body’s needs
LO Adherens Junctions
Link actin fibers in adjacent cells together
“strength” ex-myocardiocytes
LO Gap junctions
The simplest cell-cell junctions
Allow direct and rapid cell to cell communication through cytoplasmic bridges between adjoining cells.
Connected by connections to create passageways that look like hollow rivets with narrow channels through their centers (channels are able to open and close, regulating the mvmt of small molecules and ions)
LO Define an ion
A charged atom/molecule charged because number of protons in nucleus does not equal number of electrons
Carbohydrates
Either monosaccharides, disaccharides, or polysaccharides.
Monosaccharides - store chemical energy in covalent bonds ex glucose
Disaccharide - two monosaccharides stuck together ex sucrose
Polysaccharide - long chains of multiple glucose molecules ex starch and glycogen
Lipids
non polar or hydrophobic
not soluble in water because they have no charge
triglycerides - glycerol + 3 fatty acid
Steroids - estrogen, testosterone
cholesterol - important in membranes, precursor to steroids
phospholipids - amphipathic - polar phosphate head and non polar fatty acid tails
Proteins
Amino acids joined by covalent bonds (peptide bonds)
Nucleic Acids
DNA, RNA which code for proteins - contain nucleotides adenine, guanine, cytosine, and uracil
ATP, ADP, NAD, FAD also important nucleotides, which are involved in energy transfer reactions
Explain how change of matter occurs between intracellular fluid, interstitial fluid, and plasma
to get “good stuff” like oxygen to the cells. Oxygen must enter the blood from the lungs, then diffuse out of the blood into the interstitial fluid, and then diffuse into the cells.
“bad stuff” like CO2 must diffuse out of the cells into the interstitial fluid, and then into the blood and back to the lungs where it is then exhaled.
Define the central dogma of molecular biology
DNA is transcripted to make mRNA in the nucleus. mRNA leaves the nucleus and enters the cytosol where it is translated to make proteins
Primary structure of proteins
Amino acid sequence held together by covalent (peptide) bonds
Secondary structure of proteins
First level of folding either an alpha helix formation or a beta pleated sheet. Held together by hydrogen bonds
Tertiary structure of proteins
Results when the secondary structure is folded up even more. Structure is held together mostly be weaker bonds (hydrogen, ionic, van der waals)
Quaternary structure of proteins
Occurs when several different proteins are linked together EX - hemoglobin
Explain, using examples, how the 3D shape and charge distribution of a protein determines its function
The 3 dimensional shape (tertiary structure) is determined by the sequence of amino acids, which is determined by DNA. Any change in the sequence of the amino acids can change if the protein works or becomes a completely different protein than intended in the first place
T/F Homeostasis is the same thing as equilibrium
FALSE
Extracellular fluid
Plasma and interstitial fluid
Intracellular fluid
Inside the cells 67%
Interstitial fluid
Fluid between the cells 25%
Blood plasma
Fluid in the blood 8%
Explain the difference between anabolism and catabolism
Catabolism refers to chemical reactions that result in the breakdown of more complex organic molecules into simpler substances.
Anabolism refers to chemical reactions in which simpler substances are combined to form more complex molecules. Anabolic reactions usually require energy.
Describe anabolic and catabolic reactions involving carbohydrates, lipids, and proteins
Glucose goes through glycogenesis to form carbohydrates (anabolic)
Carbohydrates go through glycogenolysis to form glucose (catabolic)
Glucose, fatty acids, and amino acids go through lipogenesis to make fats (anabolic)
Fats go through lipolysis to make fatty acids and glycerol (catabolic)
Amino acids go through protein synthesis to form protein (anabolism)
Protein goes through proteolysis to form amino acids then amino acids go through gluconeogenesis to form glucose (catabolism)
The energy of ____ reactions is used to drive ____ reactions.
Catabolic; anabolic
Distinguish between oxidative phosphorylation and substrate phosphorylation with respect to the rate and amount of ATP production
Oxidative phosphorylation
-slow but high yield of ATP (abt 34 ATP molecules)
-occurs with O2 present
Substrate phosphorylation
-Fast process but low yield of ATP (abt 6 molecules ATP)
-No O2 needed
-In muscle cells (especially fast twitch) the following reaction occurs to make ATP by substrate phosphorylation
creatine phosphate + ADP ATP + creatine
Oxidative phosphorylation
Reduced coenzymes FADH2 NADH, are used to create a hydrogen ion gradient that provides the energy to power the addition of a free phosphate to ADP (via ATP synthase) to make ATP
Substrate phosphorylation
Occurs in all cells during glycolysis and the Krebs cycle. During SP a kinase enzyme removes a phosphate from a molecule and adds it to ADP.
Muscle cells are able to make ATP by SP bc they store a molecule called creatine phosphate
Diffusion
Solute moves down its concentration gradient
Simple diffusion
Small (O and CO2), lipid soluble (steroids) no carrier protein needed
Facilitated diffusion
Glucose, water - requires carrier protein
Active transport
Solute moves against its concentration gradient: membrane proteins always required
Primary active transport
ATP directly consumed (Na+K+ATPase)
Secondary active transport
Energy of ion gradient (usually Na+) used to move 2nd solute (ex nutrient absorption into gut)
Transcytosis
(Exo- and endocytosis) Large scale movements of molecules
Where is most of the water in the human body?
Inside the cells
Normal concentration gradient across a cell membrane for potassium
Higher inside the cell than outside the cell (potassium will flow out)
Normal concentration gradient across a cell membrane for sodium
Higher outside the cell than inside the cell (sodium will flow in)
Normal concentration gradient across a cell membrane for calcium
Higher outside the cell than inside the cell (Ca2+ will flow in)
Normal concentration gradient across a cell membrane for protein.
Higher inside the cell than out (protein moves out)
Normal concentration gradient across a cell membrane for oxygen
Higher outside the cell than inside
*Oxygen levels stay low in working cells because it is converted into water at the end of the electron transport chain, making sure there is always a concentration gradient
