midterms Flashcards
What are the basic characteristics of life?
- made of at least one cell
- need energy to survive (metabolize nutrients through ATP)
- respond to stimuli in their environment (environment can be inside or outside the organism)
- all living things reproduce
- grow and develop (cells dividing=growing, cells becoming specialized to do specific functions=developing)
- have DNA
- maintain homeostasis
- adapt and evolve over time
What is the difference between asexual and sexual reproduction?
asexual=doesn’t need sex cell to reproduce
sexual=needs sex cell to reproduce
What is natural selection?
survival of the fittest
when individuals with certain characteristics (adaptations) survive and reproduce while those without those characteristics die off
What is the difference between an atom and an ion?
an atom has no net charge while an ion has a net charge
In terms of the overall charge distribution on each molecule, how are polar and nonpolar molecules different?
- nonpolar=when electrons are equally distributed throughout the atoms of the molecule
- polar=when electrons are unequally distributed throughout the atoms of the molecule
How and why does the polarity of water cause certain properties?
- oxygen has a negative charge and hydrogen has a positive charge
- this makes water a polar molecule
- so since water is a polar molecule and since opposite charges attract each other, the hydrogen atom on one water molecule would be attracted to the oxygen atom of another water molecule and vice versa
- this is called hydrogen bonding/cohesion (water is more attracted to itself than other moleccules, like when sliding down a nonpolar wax paper)
- since polar molecules can be attracted to polar molecules, water can be attracted to other polar molecules and will spread out if interacting with another polar molecue
- this is called adhesion
Define hydrolysis
splitting a chemical bond by the addition of water
biochemicals can do this btw and they do it a lot
Define condesation
creating a chemical bond by removing water
biochemicals can do this btw and they do it a lot
describe carbs
- made of C, H, O
- functions: source of quick energy (mono and di), energy storage (poly), and plant structure (poly)
- monomer: monosaccharides such as glucose, fructose, galactose (1 sugar)
- (disaccharides are 2 sugars bonded together)
- polymer: polysaccharides such as starch, glycogen, cellulose (3+ sugars)
- functions: main energy source of living organisms (glucose used in cells for energy)
- its structure looks like a hexagon
describe lipids
- its structure looks like an E with chains and stuff (an E with really long horizontal lines)
- made of C, H, O
- monomers: fatty acids (–) and glycerol (|)
- polymers: fats or lipids (steroids, waxes, oils, cholesterol)
- main functions: insulation stored energy; component of hormones and cell membranes
- primary element in the carbon backbone is hydrogen
*
describe proteins
- made of S, C, H, O, N
- monomers: amino acids
- polymers: polypeptides (less than 50 amino acids) or proteins (more than 50 amino acids in a chain)
- functions: a few are assisting in digesting food, fighting diseases, structural support (muscles, bones)
- has a central carbon atom with four different components around it (the H on the bottom, the amine group on the left with one N and two H, the carboxylic acid group on the right with one O double bonded to a C which is bonded to an OH, and the variable r side chain on top)
remember honc 1234
define enzyme
- proteins needed to sustain life in living organisms
- speeds up chemical reactions by making it easier for reactants to be converted to products and does not get used up or changed during the reaction
- this reduces both activation energy (energy needed to begin a chemical reaction) and time
Define exergonic
a reaction that releases energy
Define endergonic
a reaction that absorbs energy
Define active site
a highly specific shape/chemical makeup that the substrate attaches to
Define substrate
the molecule that an enzyme acts on
How does induced fit work?
- once substrates bond to the active site, they form an enzyme-substrate complex
- as the enzyme and substrates start reacting, some of the chemical bonds in the substrate start weakening, causing them to link together
- eventually, the chemical reactions at the active site lead to the formation of a dfferent molecule (the product)
Define denaturation.
- when the pH/temp is not optimal for the enzyme to work in, this can happen
- basically change in the structure of a protein
- essentially the active site becomes messed up and unable to do its job
- the farther off the pH/temp is from its optimal level, the harder it becomes for the enzyme to work
Define inhibitors. What is the difference between a competitive inhibitor and a noncompetitive inhibitor?
molecules that slow down enzyme reactions or stop them for a period of time
COMPETITIVE
1. they bind at the active site of the enzyme
NONCOMPETITIVE
1. bind at a location that is not the active site, but it still causes the enzyme to change shape
Define metabolic pathway.
when the product of one reaction becomes the substrate for the next reaction and so on and so forth
(a series of chemical reactions characterized by multiple enzymes)
Define feedback inhibition/negative feedback. How does it work?
- when the end product of a metabolic pathway stops the metabolic pathway
- if the end product of a pathway becomes available in the environment, it’s unnecessary and wasteful for the cells to keep doing stuff so cells can just shut down the pathway if it’s unnecessary
- in feedback inhibition, the end product of a pathway reacts with the first enzyme unique to the pathway
- this occurs at the allosteric site, NOT the active site
- then that product can act as a noncompetitive inhibitor
List the components in your digestive system in order and their functions.
mouth
* salivary glands activate when they sense something that they like
* then you start chewing. munch munch
* your saliva mixes with your food
* amylase is a starch digesting enzyme in your saliva so some carb digestion happens here
* then you swallow and your food goes into the….
esophagus
* near the trachea (windpipe)
* the epiglottis is a little flap over your windpipe that stops choking
* a series of muscular contractions, known as peristalsis give the bolus to your stomach
* the lower esophageal sphincter relaxes to let the food in
* the sphincter then contracts and stops stomach contents from going up through the esophagus (basically stops heartburn or acid reflux)
stomach
* a hollow organ that holds food while it’s mixed w/stomach enzymes
* cells in the lining of your stomach secrete a strong acid and powerful enzymes that are responsible for the breakdown process
* then when it’s broken down enough to a semi solid, it goes to the….
small intestine
* a 22 foot long muscular tube made up of the duodenum, the jejunum, and the ileum
* bile emulsifies lipids (breaks them into smaller droplets) since these smaller droplets are easier for lipase to hydrolyze
* duodenum breaks down food and the jejunum and ileum absorb nutrients into bloodstream using villi (little fingerlike projections that increase the surface area of the walls of the small intestine)
* chyme, buffers, bile, and enzymes all mix here
pancreas
* no food passes through here, but it DOES make insulin, enzymes, and buffers
liver
* no food goes through here but it processes nutrients absorbed through small intestine
* also creates bile
* detoxifies harmful substances
* takes raw materials from small intestine and makes the chemicals that your body needs to function
gallbladder
* stores bile from the liver and then releases it to the duodenum
colon
* 6 foot long muscular tube from the small intestine to the rectum
* undigested food (mainly fiber and water) goes through the colon by peristalsis and water is absorbed into bloodstream and this takes abt 36 hrs
rectum
* straight 8 in. chamber that lets the body know when it’s poopytime
* as it stretches, urge to poop increases
anus
* 2 in long canal that is the pelvic muscles and two anal sphincters
* surrounded by sphincter muscles
* interal sphincter is always tight and external sphincter only relaxes when it’s poopytime
poopytime!
