exam 2 (game show review) Flashcards
what types of proteins catalyze reactions in the extracellular fluid or within the cell?
enzymes
besides lipid-soluble molecules, what other substances may freely cross the phospholipid bilayer?
oxygen
why can oxygen easily cross through the phospholipid bilayer?
because it is a small, nonpolar molecule and does not interfere with the hydrogen bonds of the water
receptor proteins, channel proteins, and recognition proteins
receptor proteins: receive signals from cell’s environment, like hormones
found on the cell membrane or inside the cell, ready to bind to molecules
channel proteins: form channels or pores that help facilitate transport of ions or molecules across cell
embedded in the cell membrane
recognition proteins: identify and interact with cells or molecules, especially in the context of the immune system
can be on cell surface or on membrane of organelles
can sodium ions, glucose, or enzymes pass freely across the phospholipid bilayer?
no
sodium ions- small but have a positive charge, require membrane proteins (protein channels) to get through
enzymes - large complex molecules, moved by processes like vesicular transport
glucose - large polar molecule, specific transport proteins like glucose transporters take it across
major histocompatibility complex (MHC) molecules are what type of membrane protein?
recognition protein
MHC molecules (major histocompatibility complex)
group of genes that code for proteins found on the surfaces of cells that help the immune system recognize foreign substances
which type of molecule is most likely to diffuse across the plasma membrane?
small and lipid-soluble (nonpolar)
what concentration does osmosis go to?
low to high concentration (water wants to go to the hypertonic area)
does osmosis occur across a membrane freely permeable to solutes?
no, only across a membrane freely permeable to water (but restricts passing of solutes)
red blood cells create in what type of solution
hypertonic
crenation vs hemolysis
crenation: cell shrivels up (in hypertonic solution)
hemolysis: cell swells and bursts (in hypertonic solution)
normal saline is which type of solution?
isotonic
- solution of 0.9% NaCl is isotonic
- greater than 0.9% is hypertonic
- less than 0.9% is hypotonic
which method of transport is responsible for low concentrations of sodium and high concentrations of potassium within the cells of the body?
active transport
the synthesis of new organic molecules is called
anabolism
“anabolic avengers”
“catabolic crushers”
a negative G value indicates that the reaction is occurring _________
spontaneously
the hydrogen atoms that arrive at the electron transport system are donated by
NADH
if radioactive sugar were fed to a mouse, the radioactivity would progress along which of the following paths?
sugar –> pyruvate –> citric acid cycle –> carbon dioxide
which cells derive all of their ATP via glycolysis?
those that function in anaerobic conditions, where oxygen is limited or absent
ertythocytes, hepatocytes, leukocytes, and neurons
erythrocytes: red blood cells
hepatocytes: liver cells
leukocytes: white blood cells
neurons: nerve cells
what happens in anaerobic conditions to pyruvate?
pyruvate generated from glycolysis gets fermented instead
which part of cellular respiration occurs in both aerobic and anaerobic conditions?
glycolysis
does glycolysis use oxygen?
no, glycolysis is the process that breaks down glucose to produce ATP without the involvement of oxygen
plants appear green to our eyes because ___________
photosynthetic pigments don’t absorb green light
which of the following happens during the light-capturing reactions of photosynthesis?
ATP is made using light energy
when a photon is absorbed by a pigment molecule, ___________
an electron in the pigment molecule is boosted (excited) to a higher energy state
as electrons pass through the system of electron carries after leaving photosystem II, they lose energy. what happens to this energy?
it is used to establish and maintain a proton gradient for the generation of ATP
what does it mean to say CO2 becomes “fixed” during photosynthesis?
CO2 becomes bonded to an organic molecule
- CO2 fixation in the Calvin cycle turns it into an organic compound like sugar
2 joined copies of a replicated chromosome are called ___________
sister chromatids
for most of their lives, cells are in __________ (cell cycle stage)
interphase
since steroid hormones, such as estrogen and testosterone, are lipid soluble, they bind to ____________
receptors inside the cell
DNA replication occurs during which phase of the cell cycle?
interphase
cells get past cell-cycle checkpoints by ________________
cdks bound to cyclins phosphorylating other proteins
