MT1 Flashcards
what kind of environment do plants and animals prefer? (hypotonic, isotonic, hypertonic)
animals - isotonic; plants - hypotonic
at resting membrane potential, is the inside or outside of the cell relatively positive?
outside of the cell is relatively positive at resting membrane potential
T or F: diffusion needs no cell energy
T; diffusion doesn’t need cell energy
T or F: hydrogen bonds keep the temperature in oceans and cells constant
T: hydrogen bonds stabilize the water; each bond formation releases heat and prevents temperature from dropping further. Increased heat energy is absorbed by energy bonds.
T or F: H bonds prevent the formation of ionic bonds
T
Does water interact with non-polar molecules, like fats?
No
Describe surface tension of water (surface tension measures how hard it is to break the surface of something)
Water forms many H-bonds at the surface and just beneath the surface, making it hard to break the surface of the water
Glycogen and starch examples of ____saccharides
polysaccharides
T or F: a chloroblast is a type of amyloblast
T
Where can an ester linkage be found?
Between a fatty acid and a glycerol on a lipid molecule;
o-c=o
Fats take up _____space and more ______ energy than carbohydrates
Fats take up LESS space and more ENERGY than carbohydrates
Why are saturated fats more closely packed?
They have single C-C covalent bonds, so are very flexible and can pack closely
Why are unsaturated fats more rigid?
Their double C=C bonds produce a liquid, oily substance that doesn’t pack closely
Hydrophilic portions point towards the ____ portion of a membrane
Outer; they want to interact with water molecules. The hydrocarbon fatty-acid tail is non-polar and hydrophobic
What can proteins do?
1) speed up chem rxns (enzymes), 2) move in/out cell (membrane transporters) 3) support cells (cytoskeleton), 4) fight microbes (antibodies), 5) allow movement (shorten + contract muscles)
Can all amino acids be produced by the body?
No, 9 amino acids must be consumed
What are the 3 parts of a nucleotide?
1) deoxyribose sugar (5-C sugar) 2) -vely charged phosphate group on 5’-C of deoxyribose sugar, 3) nitrogenous base attached to the 1’-C of the deoxyribose sugar
Enzymes add nucleotides to the ____ end of the DNA
Enzymes add nucleotides to the 3’ end of the DNA, copying them from 5’ to 3’
Name some differences between RNA and DNA
DNA: larger, always double-stranded helix; deoxyribose (2’-C), GCAU
RNA: smaller, linear, oxyribose, GCAU, more versatile than DNA, enzymes
Both: store genetic information
Why is RNA less stable than DNA?
OH group (RNA) is more EN than H group (DNA) and so the C-O (RNA) is more polar and less stable than the C-H (DNA)
unzipping DNA involves breaking what kind of bonds?
H bonds between nitrogenous bases
What is primase responsible for?
Primase is responsible for creating and attaching an RNA primer to the DNA strand (complementary base-pairs RNA nucleotides , then joins them together with a phosphodiester bond) - always between sugar and phosphate in backbone of any genetic material; writes from 5’ to 3’
What does DNA polymerase do?
1) removes primer, fills gap with DNA nucleotides
2) attach to 3’ end, add nucleotides; when it sees a RNA primer, it detaches and re-attaches at junction to keep creating nucleotides
3) builds lagging and leading strands simultaneously, with a complex that has 2 DNA polymerases connected together
What does DNA ligase do?
Connects DNA fragments - forming phosphodiester bonds between sugar and phosphate backbones
