Biology Flashcards
Mitochondria
semi-autonomous, contain some of their own genes mitochondrial DNA is passed via the mother replicate independently (via binary fission)
Serial endosymbiosis theory
mitochondria evolved from an anaerobic prokaryote engulfing an aerobic prokaryote – creating a symbiotic relationship
Rough ER
studded with ribosomes, translates proteins for direct secretion into lumen
smooth ER
Used for lipid synthesis and detoxification of drugs/poisons
transports proteins from RER to Golgi apparatus
Golgi apparatus
stacked membrane bound sacs
can introduce signal sequences with direct delivery to specific cellular location
secretory vesicles merge with the membrane, contents are released via exocytosis
Peroxisomes
contain hydrogen peroxide
primary function: breakdown long fatty acid chains via beta-oxidation
Cytoskeleton
3 components: microfilaments, microtubules, intermediate filaments
Microfilaments
solid polymerized rods of actin
actin filaments: bundles and networks resistant to compression and fracture
ex: cytokinesis, cleavage furrow
Microtubules
hollow polymers of tubulin proteins
radiate throughout the cell, provide primary pathways along motor proteins
Ex: cilia and flagella
Intermediate Filaments
keratin, desmin, etc (diverse group)
Primary fx: cell to cell adhesion, maintenance, integrity of cytoskeleton
Epithelial Cells
polarized, one side faces lumen and/or outside world, the other faces underlying vessels/structural cells
Archaea
single celled organisms, “extremophiles”, similar to Eukarya however they have a circular chromosome, divide by binary fission/budding
Resistant to many antibiotics
facultative anaerobes
can toggle between oxygen and non oxygen environments
Aerotolerant anaerobes
unable to use oxygen for metabolism
Gram staining
gram + : envelope absorbs crystal violet stain – appears deep purple
Gram - : does not absorb crystal violet stain – appears pink/red
gram +
cell wall contains peptidoglycan, aid a pathogen by providing a coat of protection
gram -
cell wall is thin, minimal peptidoglycan
contains an outer membrane with phospholipids and lipopolysaccharides
Plasmids
carry DNA not necessary for survival, so it is not considered part of “genome”, but can help in resistance
carry virulence factors “extrachromosomal”
Genetic Recombination (3 types)
(3 Types) Transformation – Conjugation – Transduction
Transformation
integrate foreign genetic material into host genome
Conjugation
sexual reproduction
2 cells form conjugate bridge (via sex pili), transfer unidirectionally
Transduction
only recombination portion that requires a vector
virus carries genetic material from one bacteria to another
Transposons: genetic elements, capable of inserting/removing themselves
Series of Bacterial Growth Phases
lag phase – exponential phase – log phase – stationary phase – death phase
Bacteriophages
viruses that specifically target bacteria (by injection), contain a capsid, and a tail sheath, tail fibers
Viral Genomes
Positive sense: genome translated to fx proteins by ribosomes (similar to mRNA)
Negative Sense: require synthesis of RNA strand complementary to it – then used as a template for protein synthesis **RNA Replicase ensures the complementary strand is made
Retroviruses
Enveloped ssRNA, cells are infected indefinitely (HIV)
*requires reverse transcriptase to synthesize DNA from ssRNA, then the DNA is integrated into the host’s DNA genome = means it must travel to the nucleus
Viral Life Cycle (Overview of steps)
Infection – Translation and Progeny Assembly – Progeny Release – Lystic and Lysogenic Cycles
Translation and Progeny Assembly
(post injection) – translation of genetic material in order to reproduce
DNA Viruses – must go to nucleus to be transcribed to mRNA
Viral genome must be returned to original form before packaging
Lystic
Bacteriophage maximal use of cell, cell swells with new visions, cell lyses, and other bacteria can then be infected
Lysogenic
If the cell does not lyse due to build up of cells, then it enters lysogenic cycle
virus will be replicated as bacterium reproduces
Prions
nonliving, infectious proteins
triggers miss-folding (reducing protein solubility, protein aggregates form, fx of cell is reduced)
Viroids
small pathogens, circular single stranded RNA
“plant pathogens”
Steps of Embryogensis
Morula – Blastula – gastrula
Gastrulation
Develops three layers:
- Ectoderm
- Mesoderm
- Endoderm
- Ectoderm
outermost layer -integument (epidermis) Develops into: Hair, nails epithelia of nose, mouth, anal canal Lens of eye nervous system and adrenal medulla
- Mesoderm
Musculoskeletal system Circulatory system Excretory system connective/muscular tissue of digestive and respiratory tracts Gonads Adrenal cortex
- Endoderm
Epithelial linings of digestive tract and respiratory tract Lungs bladder liver pancreas thyroid
Induction
differentiation due to selective transcription
one group of cells influence another group
Neurolation
development of nervous system (after three divisions form)
Notochord
rod of mesodermal cells – develops into spine
-induces group of ectodermal cells to slide inward, forms neural folds, surround neural groove, fuse into neural tube
Tip of neural fold
made of neural crest cells
migrate to form peripheral nervous system
(sensory ganglia, autonomic ganglia, adrenal medulla, Schwann cells, specific cell types in other tissues)
three types of stem cells
totipotent: greatest potency, can become anything
pluripotent: already differentiated to three germ layers
multipotent: cells within a group
Autocrine signaling
signal same cell that released the signal
Paracrine signaling
signal acts on cells in local area
Juxtacrine signaling
not usually due to diffusion, cell directly stimulates adjacent cell
Endocrine signaling
hormones that travel influence target tissue
Morphogens
cause determination of cells
based on gradients
diffuse through organize, locations closer have higher concentrations
Fetal circulation
- fHb: higher affinity to O2 than adult Hb
- R side of heart: pulmonary circulation
- L side of heart: systemic circulation
- umbilical cord: contains more arteries than veins
- oxygenation of blood occurs in placenta
Umbilical Arteries
- carry blood away from fetus to placenta (deoxygenated blood)
vs. adult arteries carry oxygenated blood away from heart/lungs to systemic circulation
Umbilical Veins
- carry blood toward fetus from placenta (carrying oxygenated blood)
vs. adult veins carry deoxygenated blood towards heat/lungs
3 fetal shunts
Foramen Ovale
Ductus Arteriosus
Ductus Venosus
Foramen Ovale
only shunt that connects the two chambers of the heart
-one way valve connects right atrium to left atrium
(allowing flow from R atrium to L atrium – thus bypassing ventricles)
-after birth, pressure differences reverses the shunts and closes them
Ductus Arteriosus
shunts leftover blood from pulmonary aorta to aorta
-direction depends on pressure differential between R and L side of the heart
Ductus Venosus
only shunt that bypasses the liver
First trimester development
-major organs develop
-heartbeat at 22 weeks
-eyes, gonads, limbs, liver start to form
@ 5 weeks: embryo 10mm
@ 7 weeks: cartilage (will become bone)
@ 8 weeks: embryo becomes a fetus
Second trimester development
tremendous growth, more amniotic fluid
-at the end: 30-36cm in length
Third trimester development
- rapid growth, brain development
- 9th month antibodies move from mother to fetus
Birth
vaginal birth “parturition”
rhythmic contractions of uterine smooth muscle
-coordinated by prostaglandins and oxytocin
Steps of vaginal birth
cervix thins – amniotic sac ruptures – strong uterine contractions – birth of fetus – placenta and umbilical cord (afterbirth) comes out
production of Myelin
produced by oligodendrocytes in CNS and Schwann cells in the PNS
Soma
- cell body that contains nucleus (location of ER and ribosomes)
- axons carry AWAY from the soma
- dendrites carry TOWARD the soma (receives incoming messages)
Astrocytes
nourish neurones
form blood-brain barrier
controls transmission of solutes
Ependymal cells
line ventricles of the brain
produce cerebrospinal fluid
physically supports the brain
shock absorber
Microglia
phagocytic cells
ingest/breakdown waste products and pathogens in the CNS
Speed of nerve impulses
increase length = slower conduction
increase cross section = faster conduction
Three mechanisms for neurotransmitter removal
- broken-down by enzymatic reactions
- can be brought back into presynaptic neuron using re-uptake carriers
- they diffuse out of synaptic cleft
Brain: grey vs. white matter
Grey matter: unmyelinated cell bodies and dendrites
White matter: axons encased in myelin
preganglionic neuron
in sympathetic and parasympathetic: release acetylcholine
Postganglionic neuron
in sympathetic: release norepinephrine
in parasympathetic: release acetylcholine
Primary difference between somatic and autonomic nervous system
peripheral ANS contains two neurons, while motor neuron in somatic NS goes directly from spine to muscle (no synapsing)
Monosynaptic vs. Polysynaptic Reflexes
Mono: single synapse between receiving sensory neuron and responding motor neuron (knee jerk)
Poly: at least one interneuron between sensory and motor neurons (withdrawal)
Two hormones to maintain water homeostasis
ADH and Aldosterone
ADH (type, produced, trigger, effect)
Type: Peptide Hormone
Produced by: hypothalamus, released by posterior pituitary
Triggered by: low blood volume and increase in plasma osmolarity
Effect: increases water reabsorption in collecting duct, to decrease plasma osmolarity
Aldosterone (type, produced, trigger, effect)
Type: Steroid hormone - Mineralcorticoid
Produced by: Adrenal glands
Triggered by: decrease in blood volume (and pressure)
Effect: increases Na/K pump (excretion K and H, reabsorb Na) to increase blood volume, increase water reabsorption
Regulated by renin-angiotensin-aldosterone system
Insulin (type, produced, trigger, effect)
Type:
Produced by: Pancreas, released by pancreatic beta cells
Triggered by: high blood glucose
Effect: decreases blood glucose levels
Glucagon (type, produced, trigger, effect)
Type:
Produced by: Pancreas, released by pancreatic alpha cells
Triggered by: low blood glucose
Effect: increases blood glucose levels (stimulates glycogenolysis)
Cortisol (type, produced, trigger, effect)
Type: steroid: glucocorticoid
Produced by: adrenal cortex
Triggered by: ACTH
Effect: increases blood glucose (by enhancing gluconeogensis, antagonizes insulin), decreased protein synthesis, inhibits immune system
Epinephrine (type, produced, trigger, effect)
Type:
Produced by: Adrenal Medulla
Triggered by: (stimulated by Sympathetic NS)
Effect: promotes glucogenolysis and fatty acid release from adipose tissue
Thryoxine (type, produced, trigger, effect)
Type:
Produced by: thyroid gland
Triggered by: (stimulated by TSH)
Effect: promotes metabolism, glycogenolysis, and sugar absorption by intestines
Calcitonin (type, produced, trigger, effect)
Type: Thyroid
Produced by: Parafollicular (C) cells in thyroid
Triggered by: high plasma calcium concentrations
Effect: decreases plasma calcium by promoting excretion by the kidneys, promotes Ca storage in bone
Two major hormones to maintain glucose homeostasis
Insulin and Glucagon
Two major hormones to maintain calcium homeostasis
Calcitonin and parathyroid hormone (negative feedback)
Parathyroid Hormone (PTH) (type, produced, trigger, effect)
Type: Parathyroid
Produced by: parathyroid gland
Triggered by: low blood calcium
Effect: increases blood calcium, bone reabsorption, decreases excretion from kidneys, increases Ca reabsorption in gut
Gonadotropin releasing hormone (GnRH) (type, produced, trigger, effect)
Type:
Produced by:
Triggered by:
Effect: promotes release of FSH and LH
Growth hormone releasing hormone (GHRH) (type, produced, trigger, effect)
Type:
Produced by:
Triggered by:
Effect: promotes release of GH
Thyroid releasing hormone (TRH) (type, produced, trigger, effect)
Type:
Produced by:
Triggered by:
Effect: promotes release of TSH
Corticotropin releasing factor (CRF) (type, produced, trigger, effect)
Type:
Produced by:
Triggered by:
Effect: promotes release of adrenocorticotropic hormone (ACTH)
Prolactin-Inhibiting Factor (PIF or dopamine) (type, produced, trigger, effect)
Type:
Produced by:
Triggered by:
Effect: inhibits release of prolactin
Follicle Stimulating Hormone (FSH) (type, produced, trigger, effect)
Type: Tropic Hormone
Produced by: anterior pituitary, release stimulated from hypothalamus
Triggered by:
Effect: promotes ovarian follicles (females), spermatogenesis (men)
Luteinizing Hormone (LH) (type, produced, trigger, effect)
Type: Tropic Hormone
Produced by: anterior pituitary, release stimulated by hypothalamus
Triggered by:
Effect: promotes ovulation (females), testosterone (men)
Adrenocorticoid Hormone (ACTH) (type, produced, trigger, effect)
Type: Tropic Hormone
Produced by: anterior pituitary, release stimulated by hypothalamus
Triggered by:
Effect: promotes synthesis and release of glucocorticoids from adrenal cortex
Peptide Hormones
-produced by hypothalamus and released by pituitary
-composed of amino acids
-Acts as a 2nd messenger, relatively large
-derived from larger proteins, cleaved during post translational processing
-Polar, water soluble
-Cannot pass through plasma membrane
-rapid onset, short lived
Ex. ADH, Oxytocin
Steroid Hormones
- those in adrenal cortex and gonads
- derived from cholesterol (-one, -ol, -oid)
- minimally polar, lipid soluble,
- Can pass plasma membrane
- bind, promotes conformational change in cytosolic and intranuclear receptors
- slow onset, long lived
- cannot dissolve in bloodstream (must be carried by proteins)
Amino Acid - derived hormones
- modified amino acids
- epinephrine, norepinephrine, triiodothyronine, thryoxine
Direct hormones vs. tropic hormones
direct: major effects on non-endocrine tissues
tropic: major effects on other endocrine tissues
Anterior Pituitary
release in response to stimulation from hypothalamus
- 4 tropic hormones (FLAT)
- 3 direct hormones (PEG)
FLAT PEG
FSH
LH
ACTH
TSH
Prolactin
Endorphines
GH
Prolactin (type, produced, trigger, effect)
Type: Direct hormone
Produced by: anterior pituitary, release stimulated by hypothalamus
Triggered by:
Effect: milk production
*increased prolactin in psychotic people on dopamine blocker medications
Endorphins (type, produced, trigger, effect)
Type: Direct hormone
Produced by: anterior pituitary, release stimulated by hypothalamus
Triggered by:
Effect: decreases pain perception, produces euphoria
Growth Hormone (GH) (type, produced, trigger, effect)
Type: Direct hormone
Produced by: anterior pituitary, release stimulated by hypothalamus
Triggered by:
Effect: grows bone, muscles, and shunts glucose towards this tissues
childhood deficiency = dwarfism
Thyroid Stimulating Hormone (TSH) (type, produced, trigger, effect)
Type: Tropic Hormone
Produced by: anterior pituitary, release stimulated by hypothalamus
Triggered by:
Effect: promotes synthesis and release of triiodothyronine and thyroxine in thyroid
Oxytocin (type, produced, trigger, effect)
Type:
Produced by:
Triggered by: giving birth
Effect: promotes uterine contractions and milk ejection (+ feedback loop)
Triiodothyronine (T3) and Thyroxine (T4) (type, produced, trigger, effect)
Type: Thyroid Hormone
Produced by: follicular cells, contains iodine
Triggered by:
Effect: increases/maintains basal metabolic rate
Cortisone (type, produced, trigger, effect)
Type: Steroid Hormone: Glucocorticoid
Produced by: adrenal cortex
Triggered by: ACTH stimulates its release
Effect:
Two hormones produced by hypothalamus and released by posterior pituitary
Antidiuretic Hormone (ADH) and Oxytocin
Adrenal Cortex and three steroid hormone classes
Glucocorticoids (cortisol and cortisone)
Mineralcorticoids (aldosterone)
Cortical Sex Hormones (androgens and estrogen)
Catecholamines (type, produced, trigger, effect)
Type:
Produced by: Adrenal Medulla (epinephrine, norepinephrine)
Triggered by:
Effect: promotes glucogenolysis, increases basal metabolic rate, increase HR, dilate bronchi, alter blood flow
Three hormones synthesized in pancreas
Glucagon
Insulin
Somatostatin
Flow of air when breathing
Air in – nares – nasal cavity – pharynx – larynx – trachea – bronchi – bronchioles
pleural
covers the lungs, lines chest wall
visceral pleura: adjacent to lung
parietal pleura: lines chest wall
Intrapleural space: lies between 2 layers, contains thin layer of fluid
Pulmonary Arteries
deoxygenated blood to lungs
Pulmonary Veins
oxygenated blood out of lungs
Adult circulatory pathway
R atrium - R ventricle - Pulmonary artery - lungs - pulmonary veins - L atrium - L ventricle - Aorta - Arteries - Arterioles - Capillaries - Venules - Veins - Vena cava - R atrium
Cardio Electrical Conduction Pathway
Sinoatrial (SA) node - Atrioventricular (AV) node - Bundle of His - Purkinje Fibers
Systole
period during ventricular contraction when AV nodes are closed, blood pumped out of ventricles
Diastole
heart is relaxed, Semilunar valves are closed, blood from atria fills in
Arteries vs veins
Arteries: thick, muscular, elastic, flow AWAY from heart
Veins: thin, inelastic, flow TOWARDS heart, valves maintain one way flow
Three Portal Systems
- Hepatic Portal System
- Hypophyseal Portal System
- Renal Portal System
Hepatic Portal System
gut capillary bed to liver capillary bed via the hepatic portal vein
Hypophyseal Portal System
Hypothalamus capillary bed to anterior pituitary capillary bed
Renal Portal System
glomerulus to vasa recta via efferent arteriole
Erythrocytes
Red Blood Cells
lack mitochondria, nucleus, and organelles to allow hemoglobin
Leukocytes
White Blood Cells
found in bone marrow: granular leukocytes and agranulocytes
Granular Leukocytes
Neutrophils, Eosinophils, and Basophils
Part of nonspecific immunity
Agranulocytes
lymphocytes and monocytes
Part of specific immunity
Thrombocytes
Platelets, required for coagulation
Innate Immunity
“Nonspecific Immunity”, always active
- noncellular components: nonspecific responses, skin, mucus, tears/saliva, stomach, complement system, interferons
- Cellular components: macrophages, dendritic cells, natural killer cells, granulocytes, neutrophils, eosinophils, basophils
Complement System
Innate Immunity
-punches holes in cell walls of bacteria, marks them osmotically unstable
Interferons
Innate Immunity
-dispersed by virally infected cells
prevent viral replication
Macrophages
ingest and present on MHC, secrete cytokines
MHC Class I: in all nucleated cells, display endogenous antigens to cytotoxic T cells
MHC Class II: in all professional antigen cells, display exogenous antigens on helper T cells
Dendritic Cells
antigen-presenting cells on skin
Natural Killer Cells
attack cells not on MHC molecules (including viral infected and cancer cells)
Granulocytes
Neutrophils: ingest bacteria, follow via chemotaxis
Eosinophils: allergen reactions, release histamine
Basophils: allergic reactions, mast cells
Two divisions of Adaptive Immune System
Humoral Immunity or Cell Mediated (cytotoxic) Immunity
Humoral Immunity
centered on antibody production by plasma cells (activated B cells)
- variable region on an antibody: tip is antigen binding region
- Memory B cells: lie and wait for the second exposure
Cell-Mediated (cytotoxic) Immunity
centered around T cells
Helper T cells: respond to MHC-II, coordinates immune sytem
Cytotoxic T cells: respond to MHC-I, kills virally infected cells
Suppressor T cells: tone down immune response, helps with tolerance
Memory T cells: similar to memory B cells
Pathway of Digestion
Oral cavity - pharynx - esophagus - stomach - duodenum- small intestine (jejunum, ileum) - large intestine - rectum
Key regulators for Ingestion/Digestion
ADH + Aldosterone: promotes thirst
Glucagon + Ghrelin: promotes hunger
Leptin and cholecystokinin: promotes satiety
Secretory cells that line the stomach
Mucous Cells: protects stomach
Chief cells: secretes pepsinogen
Parietal cells: secretes Hal and Intrinsic factor (B12 absorption)
G-cells: secretes gastrin (peptide hormone, increases Hcl secretion)
Parts of the small intestine
duodenum: primarily chemical digestion
jejunum and ileum: primarily absorption
Parts of the large intestine
cecum: accepts fluid from small intestine
colon: divided into portions
Rectum: stores feces
Segments of the nephron
- Proximal Convoluted Tubule (PCT): bulk reabsorption of glucose, amino acids, soluble vitamins, salt, water
- site of secretion of H, K, ammonia, Urea - Descending Limb of Loop of Henle: only permeable water, not salt.
- vasa recta and nephron flow in opposite directions, countercurrent multiplier - Ascending loop of Henle: permeable to salt, impermeable to water
- Distal convoluted tubule: responsive to aldosterone, salt reabsorption, waste excretion
- Collecting duct: responsive to aldosterone, ADH
Skin Layers
Epidermis then dermis then hypodermis
Layers of the Epidermis
"Can't Let Gee's Skin Bleed" stratum- Corneum Lucidum Granulosom Spinosum Basale
Layers of the dermis
Papillary layer
Reticular Layer
Langerhan Cells
special macrophages, antigen presenting at cells on skin
Sensory Cells in dermis
Merkel Cells: Deep pressure, texture Free nerve endings Meissner's corpuscles: light touch Ruffini endings: stretch Pacinian Corpuscles: Deep pressure, vibration
Three Types of Muscles
Skeletal, Smooth, Cardiac
Skeletal Muscle
support, movement, propulsion of blood in venous system, thermoregulation
-striated
-voluntary
-polynucleated
Red fibers: slow twitch, oxidative phosphorylation
White fibers: fast-twitch, anaerobic metabolism
Smooth Muscle
respiratory, reproductive, cardiovascular, digestive systems
-non-striated, involuntary, uninucleate, myogenic activity
Cardiac Muscle
Contractile tissue
- striated
- involuntary, uninucleated, myogenic activity, connected via intercalated discs w/ gap junctions
Sarcomere
Contractile unit of striated muscle
Think (myosin) + thin (actin) filaments
thin filament (troponin, tropomyosin) regulate activity
Sarcomere Structure
I band: only thin
H zone: only thick
A band: entire thick (only part that doesn’t change during contraction)
Z line to Z line is one entire sarcomere
Muscle contraction pathway
depolarization down sarcolemma – T tubules are triggered – Calcium is released – Calcium binds to troponin – Tropomyosin shifts – myosin binding sites are exposed – actin filaments bind
Tendons vs. ligaments
tendons: bone to muscle
ligaments: bone to bone
Bone remodeling
Osteoblasts and osteoclasts
PTH: increases Ca and P in blood
Vitamin D: increases production of stronger bone
Calcitonin: increases bone formation, decreases Ca in blood
Six types of Mutations (nucleotide changes)
"Please, No More Stupid Facebook Invites" Point Mutations Nonsense Mutations Missense Mutations Silent Mutations Frameshift Mutations Insertion/Deletion Mutations
Point Mutations
sub one nucleotide for another
Nonsense Mutations
sub stop codon for another amino acid
Missense Mutations
sub one amino acid for another
Silent Mutations
no effect on protein
Frameshift Mutations
Moving 3 letter reading frame
Insertion/deletion Mutations
change reading frame, all downstream amino acids are different
Five types of Mutations (chromosomal)
“I Dont Do International Travel”
Inversion Mutations: segment reversed
Deletion Mutations: lrg segment lost
Duplication Mutations: segment is copied multiple times
Insertion Mutations: segment is moved from one chromosome to another
Translocation Mutations: segment is swapped with another on different chromosome
Positive Sense-RNA viruses
stays in the cytoplasm, directly translated into proteins by host cell ribosomes
negative sense-RNA viruses
require complementary RNNA strand synthesis via RNA Replicase
DNA Viruses (post infection)
likely requires RNA polymerase
enters nucleus – transcribed into mRNA – mRNA goes to cytoplasm – translated into proteins
