test 4 review Flashcards
What is the equation for kinetic energy ?
KE= 1/2 mv^2
What happens to ratchet system (with blocks) if it is Frictionless? How does this impact Kinetic energy ?
If the rachet system is frictionless means that the height to which the block rises is taken to correspond completely to the kinetic energy of the block at the beginning of its swing (all of the final gravitational potential energy comes from all of the initial kinetic energy).
Thus assuming** NO friction means that the calculated muzzle velocity is LESS than the actual velocity** which gave the block enough initial kinetic energy both to reach the measured height h as well as to overcome the negative work done by friction.
What happens if a system has friction ? How is KE and velocity affected ?
However, if there were Friction, then that final height h would be due not only to the initial kinetic energy but also to the negative work done by friction.
**Reaching the same height h with friction thus requires more initial kinetic energy than reaching it without friction, and more kinetic energy implies a greater muzzle velocity.
What is the equation for conservation of mechanical energy ?
law of conservation of mechanical energy:
Change in KE= - change in PE (potential energy)
KEi + PEi = KE f + PE f
What is equation for non-conservative forces?
Non-conservative forces
Kei + PEi + Work done by nc = KEf + PEf
What are examples of non-conservative forces?
kinetic friction, drag
non-conservative forces do negative work and if they are doing work, mechanical energy NOT conserved
what are examples of conservative forces?
Spring force, electrostatic forces, and gravity, have potential energy associated with them.
-if these forces are doing work, than mechanical energy is conserved
What is the equation for change in potential energy ?
Change in PE: mg x change in height
What is the equation for elastic potential energy for compressed spring?
The elastic potential energy of the compressed spring,= 1/2)kx^2,
What is kinetic molecular theory ?
states that gases are in constant motion and have perfectly elastic collisions
What happens to molecules with intermolecular attractions ? How is PE and KE affected?
Intermolecular attractions Increase the potential energy (PE) between molecules, Decreasing their kinetic energy (KE ).
What is the periodic trend for atomic radius of elements F2, Cl2 and Br2 ?
Atomic size increases To left and DOWN,
hence F2 < Cl2 < Br2
(Br is largest)
What happens to polarizability, with increasing size and number of electrons? How does this affect LDFs ?
With increasing size and number of electrons comes a GREATER polarizability, which increases the strength of the element’s London dispersion forces.
What are the characteristics of facultative anaerobes ?
A facultative anaerobe can survive through fermentation when oxygen is not available, but will use oxidative respiration when oxygen is available.
Which process can undergo both aerobic and anaerobic conditions ?
Glycolysis
Glycolysis will occur under both aerobic conditions (in which case the pyruvate will go on to enter the Krebs cycle as acetyl-CoA) and under anaerobic conditions (fermentation reduces pyruvate to alcohol or lactate),
What process only occurs under anaerobic conditions ?
Fermentation
which processes can only occur under aerobic conditions ?
Krebs cycle and Oxidative phosphorylation
What is specific gravity ? What is the sp gr for water?
measure of density with respect to density of pure water?
sp gr H2O : 1 g/mL or 1000 kg/m^3
What is the first step of gluconeogenesis? Which enzyme ?
In the first step of gluconeogenesis, pyruvate is also converted into OAA (by the enzyme pyruvate carboxylase).
What reaction occurs with PEPCK (phosphoenol pyruvate carboxykinase) ?
OAA is converted into phosphoenolpyruvate (PEP) by the enzyme phosphoenolpyruvate carboxykinase (or PEPCK).
this occurs in gluconeogenesis
what will happen to glutamic and aspartic acid at physiological pH?
At physiological pH (about 7.4), both the carboxylic acid end of the amino acid and the side chain COOH will be DEPROTONATED. T
his is because physiological pH is above the pKa values for these acidic protons (carboxyl pKa is approximately 2, and the R-group pKa is approximately 4). Thus, aspartic acid will actually be in its aspartate form, and will have two deprotonated carboxylic acid groups at physiological pH
what happens to amino group side chains if pH is greater than pka?
PH > Pka, the amino acid will be deprotonated
What is the role of parietal cells? What does HCl do?
. Parietal cells are found in the stomach and are responsible for producing HCl, which causes the stomach contents to have a low pH. HCl also non-specifically digests proteins by cleaving peptide bonds, and activates pepsinogen.
What happens if parietal cells are elevated?
Elevated parietal cell secretions would mean more acid, and a lower gastric pH .
More acid would also lead to slightly more protein break down