Biology/Biochem Flashcards
Surfactant ____ surface tension in the alveoli
surfactant reduces surface tension in the alveoli
low surface tension is required to prevent collapse in the alveoli.
Describe the steps of the cross-bridge cycle
- Ca+ binds to troponin causing confirmational change in tropomyosin to expose the myosin binding site on actin
- myosin head, connected with ADP + Pi, binds to actin
- ADP +Pi dissociates from myosin head causing power stroke
- a new ATP molecule attaches to myosin head, causing it’s release from actin (release of cross-bridge)
- ATP hydrolyzes to ADP + Pi returning myosin head to cocked position (recocks)
what is the complement system and what are the 4 steps ?
a part of the immune system that enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promotes inflammation, and attacks the pathogen’s cell membrane
- opsonization: antigens are tagged for phagocytosis
- chemotaxis: cytokine and chemokines used to attract macrophages to site of infection
- cell lysis: membrane of foreign cell is destroyed
- agglutination: antibodis used to cluster and bind pathogens together so the immune system can mount an attack
incomplete dominace vs. codomance?
incomplete dominance results in a blended phenotype in heterozygotes
codominance shows both alleles expressed distinctly, with no blending
the main excitatory neurotransmitter in the CNS is
glutamate
the main inhibitory neurotransmitter in the spinal cord is
glycine
the main inhibitory neurotransmitter in **CNS **is
GABA
Give the steps to the GPCR sequence:
1 - Ligand binds to GPCR
2 - GPCR undergoes conformational change
3 - Alpha subunit exchanges GDP for GTP
4 - Alpha subunit dissociates and regulates target proteins
5 - Target protein relays signal as 2nd messenger and triggers cascade response
6 - GTP is hydrolyzed to GDP, everything returns to its original place, ready to repeat the sequence
How is DNA read and replicated?
DNA is read 3’ to 5’ and synthesized 5’ to 3’
the excitatory neurotransmitter in the CNS is
glutamate
negative ion form of glutamic acid, an acidic amino acid
the main inhibitory neurotransmitter in the brain is
GABA
contains 4 carbon amine group and carboxylic acid group
the main inhibitory neurotransmitter in the spinal cord is
glycine
nonpolar amino acid
what forms the blood brain barrier between cerebrospinal fluid and intersitial fluid of the CNS?
ependymal cells
what makes myelin in the CNS vs PNS?
Oligodendrocytes make myelin in the CNS. Schwann cells make myelin in the PNS
What are enhancer elements?
enhancer elements are regions of DNA that interact with transcription factors to promote gene expression
upstream of a gene interacts with the RNA polymerase through DNA looping
