Chapter 2 - Molecules & Cells in Animal Physiology Flashcards
Where are simple squamous epithelium commonly found?
Found in skin cells, cheek cells, capillaries, and alveoli of the lungs.
Where are simple cuboidal epithelium commonly found?
In organs that are specialized for secretion, such as salivary glands and thyroid follicles, and those that are specialized for diffusion, such as the kidney tubules.
Where are simple columnar epithelium commonly found?
Stomach, uterus, small intestine, and large intestine.
Which epithelium are found in the small intestine and why?
Simple columnar, because these long cells are specially adapted for absorption and secretion.
What junctions block paracellular paths?
Paracellular paths or paths between cells are blocked by tight junctions that interfere with paracellular movements of substances through the epithelium.
What is the difference between catabolism and anabolism?
Catabolism involves molecules being broken down to their smaller building blocks to RELEASE energy, while anabolism involves more complex molecules being created from smaller building blocks that USE energy.
Thinking back to the frog and toad example, which would win in a leaping contest and why?
The leopard frog would win because the toad does not have much lactate dehydrogenase, which acts to change pyruvic acid to lactic acid that can then be generated into ATP. The toad is forced to make ATP without oxygen which is difficult, their slow rate of oxygen delivery to the muscle means that there will be a slow rate of ATP production. This is why they cannot hop as fast as the leopard frog.
In the LDH equation, what are the substrates and what are the products?
Substrates: NADH2 & pyruvic acid
Products: lactic acid & NAD
How can you increase the reaction velocity?
Reaction velocity is the amount of substrate that is converted to product per unit of time.
-To increase this, the substrate concentration must also be increased until it reaches a maximum point.
What is the difference between hyperbolic kinetics and sigmoid kinetics?
Hyperbolic kinetics: each enzyme has just one substrate-binding site for particular substrate of interest OR multiple sites that are independent of each other.
Sigmoid kinetics: each enzyme has multiple substrate-binding sites that influence each other.
What two properties influence maximum velocity at which a saturated enzyme-catalyzed reaction converts substrate to product?
- The NUMBER of active enzyme molecules present
2. The catalytic EFFECTIVENESS of each enzyme molecule, or turnover number (kCat)
What is maximum velocity or Vmax?
The saturated enzyme-catalyzed reaction converts substrate to a product at this point.
What is the difference between a transition state and activation energy?
Transition state: intermediate chemical state that a substrate must pass through to form a product molecule
Activation energy: the amount of energy necessary for a molecule to REACH the transition state
What is enzyme-substrate affinity?
The proclivity of enzyme to form a complex with a substrate when they meet.
Does it take more or less concentrated substrate to reach one-half of the maximum reaction velocity of the enzyme and substrate have a high affinity?
The Km or one-half maximum reaction velocity and the enzyme-substrate affinity are inversely related, so
as Km increases, the affinity decreases.
What is a ligand, what is an example of a ligand?
Ligand: molecule that selectively binds via noncovalent bonds to a structurally and chemically complementary binding site on specific proteins.
i.e. testosterone is an example
What is cooperativity?
It is the relationship between the ligands that bind.
Positive: ligand binding at one site FACILITATES binding of other sites on the same molecule
i.e. testosterone
Negative: ligand binding at one site INHIBITS binding of other sites on the same molecule
i.e. oxygen to hemoglobin
