biology midterm!

DNA

deoxyribonucleic acid

three parts of a nucleotide

deoxyribose sugar, phosphate group, nitrogen base

which part of a nucleotide is the genetic material?

nitrogenous (nitrogen base)

why is the order of the nitrogenous bases important?

the nitrogenous bases get read 3 letters at a time as mRNA codons at the ribosome. Each set of 3 letters of DNA ultimately codes for one amino acid.

deletion

a single nucleotide is deleted from the DNA sequence. EX: ATT GGC

insertion

a single nucleotide is added into the DNA sequence. EX: ATT GGC

substitution

one base is switched with another

frameshift mutation

when a base is inserted or deleted it pushes the remaining bases forwards or backwards. This causes a shift in the reading frame in which you read mRNA 3 letters or one codon at a time.

silent mutation

an error in DNA that does not cause a change in the protein produced; a mutation that does not affect the organism.

RNA

ribonucleic acid

mRNA (messenger RNA)

the DNA code rewritten in a single

tRNA (transfer RNA)

tRNA molecules transport amino acids to the ribosome and drop them off during translation; tRNA anticodons pair with the codons on mRNA.

rRNA (ribosomal RNA)

simply the ribosome; the ribosome is made up of a small and large subunit.

strands of DNA

2 strands

strands of RNA

1 strand

type of sugar in DNA

deoxyribose

type of sugar in RNA

ribose

nitrogenous bases in DNA

adenine, thymine, cytosine, and guanine

nitrogenous bases in RNA

adenine, uracil, cytosine, guanine

DNA location in cell

confined to the nucleus

RNA location in cell

can leave the nucleus; found in nucleus, cytoplasm, & ribosome.

transcription

rewriting DNA into mRNA

what happens in transcription

RNA polymerase splits the double helix and creates a complementary strand of RNA

where does transcription happen

nucleus

what enzyme is involved in transcription

RNA polymerase

promoter

a sequence that indicates the start of a gene; the location where RNA polymerase attaches to the DNA molecule.

which types of RNA are involved in transcription?

only mRNA

explain slicing of introns from pre

mRNA.

translation

using the mRNA code to make a protein

what happens in translation

mRNA is read 3 bases (1 codon) at a time by the ribosome. for every codon, a tRNA molecule with a matching anticodon brings an amino acid to the ribosome. Amino acids are bonded together with peptide bonds as the ribosome works down the mRNA molecule. Translation stops when the ribosome reaches a STOP codon, causing the ribosome to detach from the mRNA.

where does translation happen?

ribosome

which types of RNA are involved in translation?

mRNA, tRNA, rRNA (ribosome)

what does a STOP codon do?

stops translation; no more amino acids are added to the polypeptide chain and the ribosome detached from the mRNA molecule.

why is the genetic code redundant?

multiple codons code for the same amino acid.

what is another term for the cell membrane?

plasma membrane

homeostasis

maintaining a balance between the inside of the cell and the outside environment of the cell.

function of the cell membrane?

regulate what goes in and out of the cell and protection. aids in maintaining homeostasis in a cell.

what two groups of biomolecules make up the cell membrane?

lipids and proteins

which type of organic molecule forms a bilayer in the cell membrane?

lipids

which type of organic molecule makes up the channels that help to move materials in and out of the cell?

proteins

which type of organic molecule makes up the pumps that push materials against their concentration gradient?

proteins

what is the function of a marker protein?

allows for differentiation between body cells and foreign cells.

selectively permeable (semi

permeable)?

equilibrium?

the state of balance or static; the absence of net tendency to change.

is energy needed for passive transport & why?

no, substances of molecules move WITH the concentration gradient from an area of high concentration to low concentration.

does passive move WITH or AGAINST the concentration gradient?

with

osmosis

the movement of water from an area of high water concentration to an area of low water concentration through the membrane of a cell.

what is distilled water?

100% water, pure water, a hypotonic solution

what is the shrinking of the cytoplasm called?

plasmolysis

what liquid could have been added to the cells to cause the cytoplasm to shrink?

a hypertonic solution like salt water, syrup, etc.

what is the roll of the cell membrane in plasmolysis?

it allows water to enter and exit the cell.

substance being dissolved?

solute

substance that does the dissolving?

solvent

hypertonic?

the concentration of solute is higher outside of the cell compared to the inside of the cell.

example of hypertonic solution

sea water (compared to cells in humans)

how would a cell respond if placed in a hypertonic solution?

the cell would shrivel because there is a higher amount of solute outside the cell than inside the cell.

hypotonic

the concentration of solute is lower outside of the cell compared to the inside of the cell.

example of hypotonic solution?

distilled water

how would a cell respond if placed in a hypotonic solution?

the cell would fill, swell, and possible lyse (burst) because there is more solute on the inside of the cell than outside.

why would a hypotonic environment like a freshwater lake be a dangerous habitat for a saltwater fish?

the cells in the saltwater fish would gain too much water and burst (lyse) killing the fish.

isotonic

the concentration of solute is the same inside and outside of the cell.

example of isotonic solution

tap water (in relation to plant cells)

how would a cell respond if placed in an isotonic solution?

the cell would maintain equilibrium and would remain the same size because water is moving in and out of the cell at equal rates.

diffusion

the movement of a solute molecules from an area of high concentration to an area of low concentration.

facilitated diffusion

the movement of a substance from an area of high concentration to an area of low concentration with the help of membrane proteins.

what proteins aid in facilitated diffusion?

carrier and channel proteins

what kind of molecules move through protein channels?

large molecules like glucose.

what is the difference between diffusion and osmosis?

diffusion is movement of solutes while osmosis is movement of water.

what is the difference between diffusion and facilitated diffusion?

diffusion is the unaided movement of particles from areas of high concentration to areas of low concentration, facilitated diffusion requires a "helper" protein to move large molecules with their concentration gradient.

is energy needed for active transport & why?

yes, substances are moved AGAINST their concentration gradients from an area of low concentration to an area of high concentration which requires ATP.

does active move WITH or AGAINST their concentration gradient?

against

protein pump

proteins that pump ions across the cell membrane using ATP as the energy source.

example of protein pump?

sodium

why do protein pumps require energy?

substances are moved against their concentration gradient form an area of low concentration to an area of high concentration.

vesicle?

a small fluid filled sac used to transport materials inside the cell.

endocytosis?

a cellular process in which substances are brought into the cell; REQUIRES energy.

exocytosis?

a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane. REQUIRES energy.

is a cell is unable to manufacture ATP, what cellular process(es) would not occur?

enzymatic reactions (DNA replication, cell division, metabolism), active transport, cell movement.

aqua

water

cyt / cyto

cell

en / endo

inner

ex / exo

outer

homeo / homo

same

hyper

above, excessive

hypo

below, insufficient

iso

equal, same

lys

to break down

phag / phago

to eat

stasis

remain the same

write complementary strand:TAACGGTC

ATTGCCAG

what pairs with adenine?

thymine

what pairs with cytosine?

guanine

what pairs with guanine?

cytosine

what pairs with thymine?

adenine

what are the monomers of DNA?

nucleotides

what two parts of a nucleotide make up the backbone of the DNA molecule?

deoxyribose sugar & phosphate

what kinds of bonds hold together the two strands of DNA?

hydrogen bonds

when are chromosomes visible during the cell cycle?

during mitosis (prophase, metaphase, anaphase & telophase)

what biomolecule are chromosomes primarily composed of?

nucleic acid (DNA)

one strand of the DNA molecule runs 5' to 3' while the other strand runs 3' to 5'. what is this called?

antiparallel