review - exam 1 Flashcards
polymers found in insects
chitin & glycogen
monomers connected together via dehydration synthesis to make cellulose, glycogen, & starch
glucose
what role do enzymes play in in building & breaking down macromolecules
enzymes act as catalysts that increase the rate of reaction to build up or break down macromolecules
alpha-helix vs beta-sheet structure in proteins
both are an example of secondary structure
both may be present in globular proteins
the structure of both are maintained by hydrogen bonding
what type of bond holds the amino acid together
peptide
hydrophobic exclusion
hydrophobic molecules tend to stick together in water to avoid contact
what is the relationship between a gene & a protein?
protein coding genes contain the info to make a protein
why is transcription necessary
it makes an RNA copy of the gene
RNA can leave the nucleus & be used in translation
mRNA
messenger
carries info used to make proteins
has codons
tRNA
transfer
used in translation
connects codons & amino acids
rRNA
ribosomal
makes up part of ribosomal structure
snRNA
small nuclear
involved in RNA splicing
which direction is RNA transcribed
5’ - 3’
AWAY from the promoter
explain how eukaryotic mRNAs get out of the nucleus
through nuclear pores
polyA binding proteins bind to tail
binding proteins have nuclear export signals which direct the binding proteins & mRNA out of cell
what is alt RNA splicing
in different cells & conditions pre-mRNA can be interpreted differently
1 gene –> 1 pre-mRNA –> multiple mature mRNAs –> multiple proteins
how to increase membrane fluidity
more unsaturated fatty acids
shorter tails
less proteins
more cholesterol
what types of molecules can easily move across a phospholipid bilayer
steroids, hormones, & gases
what types of molecules have DIFFICULTY passing the bilayer
ions & large molecules
example of substance moved by simple diffusion
hormone
example of substance moved by facilitated diffusion
ions
example of substance moved by active transport
ions
osmosis
sometimes proteins (for rapid)
energy needed
movement down concentration gradient
example = water
explain how cholesterol enters your cells
apo protein on LDL complexes binds to LDL receptors on the plasma membrane
cell brings in the LDL by receptor-mediated endocytosis
LDL can be broken down & LDL receptors are recycled back into membrane
what structures make up the endomembrane system
transport vesicle
lysosome
golgi apparatus
rough & smooth er
plasma membrane
lysosome
molecules broken down by hydrolysis
part of endomembrane system
peroxisome
molecules broken down by oxidation
lines of evidence that support the theory that mitochondria & chloroplasts were once free living prokaryotic cells
same size as avg pro cell
have double membranes
have ribosomes
circular chromosomes
divide by the same mechanism as bacteria
what produces Okazaki fragments
DNA Pol III
what stabilizes the replication bubble
single stranded binding proteins
