BioCHEM/BIO Flashcards
(341 cards)
1
Q
how many functional groups do amino acids have? and what are they?
A
amino acids contain two functional groups which are:
- amino group (-NH2) and a carboxyl group (-COOH).
2
Q
what element joins the -NH2 and -COOH in amino acids? what forms the centre of an amino acid?
A
the ALPHA carbon of the carboxylic acid! which also forms the centre of an amino acid
3
Q
do all amino acids need to have the amino and carboxyl groups bonded to the same carbon (ie. alpha carbon)?
A
no!
4
Q
what are the 20 alpha amino acids also known as?
A
proteinogenic amino acids
5
Q
all 20 amino acids are ____ amino acids.
L or D? is there an exception? if yes, explain
A
L-amino acids. no exceptions
6
Q
out of the 20 amino acids, how many are chiral? which are not chiral?
A
19/20.
Gly is NOT chiral
7
Q
all 20 amino acids have _____ configuration. is there an exception? if yes, explain
A
(S) absolute configuration
Exception: cysteine because it has an -CH2SH group that has a priority higher than COOH, therefore, has an R absolute configuration
8
Q
one example of an amino acid that exists in eukaryotes and is D amino acid
A
gramicidin which is an antibiotic produced by a soil bacterium called Bacillus brevis. D and L alternate in primary structure
9
Q
which amino acid has imidazole?
A
Histidine
10
Q
what makes use of the histidine’s side chain’s ability to gain a proton?
A
chymotrypsin
11
Q
list hydroPHOBIC amino acids with long alkyl side chain
A
A
I
L
V
P
12
Q
List hydroPHILIC amino acids
A
R
H
L
E
D
N
Q
13
Q
_____ found at surface of proteins while ______ interiololy
A
hydrophilic
hydrophobic
14
Q
what is the usual pI of amino acids with non-ionizable side chains?
A
around 6
15
Q
what are the four fundamental tenets of the cell theory?
A
all living things are composed of cells
the cell is the basic functional unit of life
cells arise only from preexisting cells
cells carry genetic information in the form of DNA that can be passed on from one generation to the next (ie. from parent to daughter cells).
16
Q
are viruses considered living organisms? if yes, explain. if no, explain
A
viruses are NOT considered living organisms because they violate the third and forth tenets of the cell theory. For example, they are unable to reproduce on their owns unless they invade human body or bacteria, and they use other organisms’ RNA to replicate and produce their viral components.
17
Q
prokaryotes are ______ celled while eukaryotes are ______. Prokaryotes _____ a nucleus while eukaryotes ______
A
prokaryotes are single celled while eukaryotes are unicellular or multicellular. Prokaryotes lack a nucleus while eukaryotes contain a nucleus.
18
Q
what is unique about the membrane of most eukaryotic organelles?
A
the membrane is unique because its surface is hydrophilic and electrostatically interacts with the aqueous environment. while the inner of the portion is hydrophobic allowing for selective movement.
19
Q
why are organelles in eukaryotes membrane bound?
A
to allow for compartmentalization
20
Q
what does compartmentalization mean?
A
the way how organelles are separated on confined area to allow each to perform its role, and build a productive space.
21
Q
what is the main function of cytosol?
A
allows for the diffusion of molecules throughout the cell.
22
Q
what is the “darker” spot inside the nucleus referring to?
A
the nucleolus
23
Q
where does rRNA synthesis take place?
A
in the nucleolus
24
Q
is the nucleus a membrane enclosed organelle?
A
yes, the nucleus contains a nuclear membrane or an envelope that is double membrane, and maintains a proper environment for the nucleus separate from the cytoplasm
25
what allows for selective distribution between nucleus and cytoplasm?
nuclear pores (NOT membrane) which allows for selective movement between external environment (cytoplasm) and the nucleus.
26
order: in terms of formation NOT size!!
chromosomes, genes, DNA, histones
genes --> DNA --> histones wrapped around --> chromosomes.
27
order: in terms of size!!
chromosomes, genes, DNA, histones
Chromosomes > DNA > genes> Histones
28
how many layers does the mitochondrion contain?
two layers.
layer 1: the outer layer: which serves as the barrier between the cytosol and the inner environment of the mitochondrion.
layer 2: the inner layer: which is arranged into numerous infoldings called cristae.
29
why is the cirstae in mitochondria important?
it contains the molecules and enzymes for ETC, it is highly convoluted which increases the SA for ETC.
30
what is the space between the inner and outer layer of the mitochondira called?
inter-membrane space
31
what is the space of the inner membrane called?
matrix.
32
in the simplest way possible, how is the proton motive force established? (hint: think of the layers of the mitochondria). what happens next?
proton motive force is established when the protons are pumped from the matrix to inter-membrane space. They then flow through ATP sythatase to generate ATP during oxidative phosphorylation
33
what does it mean when we say: " mitochondria are semi-autonomous"?
they have their own DNA and replicate seperatly BUT still need the cell's nucleus for a variaty of functions
34
what process do mitochondria use to replicate?
binary fission
35
what is cytoplasmic or extranuclear inheritance?
the transmission of genetic material independent of the nucleus.
36
how are mitochondria thought to have originated?
when the engulfing of an aerobic prokaryotes by an anaerobic prokaryotes resulted in a symbiotic relationship.
37
how are mitochondria related to apoptosis?
they are capable of killing the cell by releasing enzymes from the ETC
38
where do endosomes transport materials for degradation?
to the trans-golgi, to the cell membrane, or to the lysosomal pathway
39
how are the degradative enzymes of lysosomes prevented from escaping the lysosome and going into the cytoplasm?
through the lysosomal membrane that squesteres these enzymes.
40
what does autolysis mean?
the release of enzymes (ie. lysosomal enzymes)
41
what happens when lysosomes release their hydrolytic enzymes?
apoptosis
42
what are the three components of cytoskeletin?
microfilaments
microtubules
intermediate filaments
43
_______ provides conduit for the transport of materials around the cell
cytoskleletin
44
what is the primary function of peroxisiomes?
the breakdown of very long chain fatty acids via beta oxidation.
45
______ participate in the synthesis of phospholipids and contain some of the enzymes involved in the pentose phosphate pathway
peroxisiomes
46
list at least three roles of smooth ER.
primarily for lipid synthesis, and detoxification of certain drugs and poisions. Also, transports proteins from RER to the GA
47
what are some modifiers to the materials moved to the GA?
phosphates, sulfates, and carbohydrates.
48
what is another unique way that golgi apparatus modifies materials? (other than phosphates, sulfates, and carbohydrates.)
through signal sequences
49
distinguish between:
microfilaments
microtubules
intermediate filaments
microfilaments: made up of solid polymerized rods of actin that are organized into bundles of networks and are resistant to both compression and fracture providing protection for the cell.
microtubules: are hallow polymers of tubulin proteins, and provide the primary pathways along which motor proteins like keesin and dynein carry vesicles.
intermediate filaments: include keratin, desmin, vimentin and lamins. they are able to withstand large amount of tension which increases the structural rigidity of the cell, they also help anchor other organelles.
50
how are the cleavage furrow formed in mitosis?
from the microfilaments which organize as a ring at the site of division between the two new daughter cells. As the actin filaments within this ring contract, the ring becomes smaller, eventually pinching off the connection between the daughter cells
51
cila and flagella are a type of ______ cytoskeletins
microtubules
52
what is the structure of cilia and flagella known in eukaryotes
9+2 structure
53
list the types of tissues
epithelial
connective
muscle
nervous
54
what are epithelia cells mainly involved in?
absorption
secretion
sensation
55
epithelial cells vs. basement membrane?
epithelial cells are joined to each other AND to an underlying layer of connective tissue known as the basement membrane
56
what does parenchyma mean? give an example.
the functional parts of the organ (ie. epithelial cells contain parenchyma)
example: nephrons in kidneys are composed of epithelial cells; nephrons are the functional units of the kidneys
57
what does it mean when we say "epithelia cells are polarized"? give an example.
one side faces the lumen or the outside world, and the other interacts with underlying blood vessels and structural cells. for example, in the small intestines, one side of the cell is involved in absorption while the other is involved in releasing nutrients into circulation
58
epthelial cells with one layer of cells are known as
simple
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epthelial cells with multiple layers of cells are known as
stratified
60
epithelial cells that appear to have multiple layers due to differences in cell height but are only one layer are known as
pseudostratified
61
cells that are cube-shaped are known as
cuboidal
62
cells that are long and thin are known as
columnar
63
cells that are flat and scale like are known as
squamous
64
epithelial cells are considered parenchyma, what about connective?
stroma! which means structural support.
65
how is the extracellular matrix formed?
connective tissues containing cells secrete collages and elastin to form extracellular matrix
66
a child diagnosed with an enzyme deficiency that prevents the production of hydrogen peroxide. what is the outcome?
the perixosomes would not function properly, and as a result they won't be able to digest long fatty acids
67
structure of centrioles
they are structured as none triplets of microtubules with hallow center.
68
an alpha cell that produces glucagon in pancrease is an epithelia or connective tissue cell
epithelial
69
define prions
nonliving things that cause disease by triggering the misfolding of proteins usually through the conversion of a protein from alpha helices to beta sheets which reduces the solubility of a protein and the ability to degrade the protein
70
define viroid
small pathogens consisting of a very short circular single stranded RNA that infect plants. they bind to large number of RNA sequences and can silence genes in the plant genome preventing the synthesis of necessary proteins resulting in metabolic disruption and structural damage to the cell.
71
examples of humans viroid?
HDV (heptits D)
72
is HDV alone innocuous?
yes (harmless), but when coinfected with HBV, it can silence human hepatocytes.
73
hepatocytes
cells in liver
74
process of extrusion
virus can leave the cell by fusing with its plasma membrane, and the host cell remains alive allowing for the continued use of the host cell by the virus.
75
during extrusion, the virus is at the state of?
in a productive cycle
76
location of genetic material from postive and negative sense RNA viruses?
positive: cytoplasm where it is directly translated into protein bu the host cell ribosomes
negative: requires synthesis of a complementary RNA strand via RNA replicase which can then be translated to form proteins
77
differences between HIV and bacteriophage with the way they enter the cell?
HIV: fuse with the membrane
bacteriophage: inject their genetic material
78
life cycle of HIV?
1. virus binds to CD4 and CCR5
2. empties its content into the cell as it fuses
3. the reverse transcriptase makes a copy of viral RBA and created dsDNA
4. this dsDNA is insterted into the host cell's DNA by the viral enzyme intefrase
5. the cell (infected) divides making long chains of proteins
6. viral RNA and proteins move to the cell membrane to begine the process of new virus creation
7. enzyme protease modifies the protein chain aspart of the process of creating mature virus
79
negative sense RNA vs positive
positive-sense RNA refers to RNA that can be directly translated by host cell ribosomes, acting as mRNA. Negative-sense RNA, on the other hand, is complementary to mRNA and must be converted into positive-sense RNA by an enzyme before it can be translated
80
how do negative sense RNA ensure complementary strand is synthesized?
carry an RNA replicase in the virion
81
describe retroviruses
- enveloped
- single stranded RNA
- family: retroviride
82
retroviride
viron containing two identical RNA molecules
83
tail sheath vs fibres
sheath: "syringe"
fibre: recognize the target
84
transfer in conjugation is ____
unidirectional
85
pathway during conjugation
from donor male to recpient female
86
sex pili
bridge appendages during conjugation
87
what must the bacteria contain during conjugation?
sex factor (plasmid)
88
bacteria with sex factor are known as?
F+
89
F___ is converted to F____
- to +
90
mutualistic symbiosis?
both humans and bacteria benefit
91
spherical bacteria and example
cocci
streptococcus pygones
92
rod shaped bacteria and example
bacili
E. coli
93
spiral shaped bacteria and example
spirlli
reponema pallidium
94
flagella structure, explain
filament is hallow, helical structural composed of flagellin. the basal body is a complex structure that anchors the flagellum to the cytoplasmic membrane is also the motor of the flagellum which rotate at a rate up to 300 Hz. The hook connects to the filament and the basal body so that as the basal body rotates, it exerts a torque on the filament which thereby sopings and propels the bacterium forward.
95
do Archaea have flagella?
yes but different than bacterial
96
what separates the peptidlygcan and the cell membrane?
periplasmic space
97
cell wall vs. cell membrane vs. envelope?
wall: forms the outer barrier of the cell
next layer is membrame composed of phospholipids
wall and membrane = envelope
98
are autosomal cells in animals, diploid or haploid? what about germ cells?
diploid (2n) -> autosomal cells
haploid -> germ cells
99
what are the four stages of cell division?
G1
S
G2
M
100
what are the stages of interphase?
G1
S
G2
101
at what stage do cells spend almost their entire time at?
interphase around 90% of their time!
102
what if cells do not want to divide? at which stage do they remain?
G0 stage!
Which is in the G1 stage, they are living cells and have a function but with out any cell division preparations
103
describe the overall structure of the chromosomes in interphase
the chromosomes are not visible with light microscopy because they are in a less condensed form known as chromatin.
104
chromosomes are in a less condensed form at interphase, why is that?
they are at the chromatin state because the RNA polymerase will have more access for transcription.
105
describe the overall structure in mitosis
condensed DNA and coiled chromosomes to avoid losing any genetic material
106
What is the G1 stage known as? explain this stage
Pre-synthetic stage
- cell is creating organelles for energy and protein production
- increasing in size
- regulated and controlled by restriction points to ensure the proper complement of DNA
107
What is the S stage known as? explain this stage
Synthetic stage
- cell replicates its genetic material so that each daughter cell will have identical copies
- after replication, each chromosome consists of two identical chromatids that are bound together by the centromere.
- poloidy cells do not change; still 46 chromosomes but 92 chromatids
108
What is the G2 stage known as? explain this stage
Post-synthetic stage
- another restriction point to ensure there are enough organelles and cytoplasm for the two daughter cells. and ensure that DNA replicated proceeded correctly to avoid passing any mutations
109
Stages of mitosis
Prophase
Metaphase
Anaphase
Telophase
cytokinesis
110
chromatid vs chromosome vs centromere
Two CHROMATIDS bind together through the CENTROMERE to form a single CHROMOSOME
111
genetical similarity in daughter cells during mitosis vs meiosis?
identical (genetically) in mitosis
NOT identical in meiosis
112
how many checkpoints during the cell cycle? locations?
G1/S
G2/M
113
Main goal of the G1/S checkpoint?
- cell checks the DNA is good enough to replicate in the S phase
- any error detection the DNA will be repaired
114
Main goal of the G2/M checkpoint?
- ensure the right size and amount of organelles (doubled) for each daughter cell to get
115
true player during checkpoints in cell cycle?
p53
116
the molecules responsible for the cell cycle?
cyclins and cyclin dependent kinases (CDK)
117
how are CDKs activated?
CDK require the presence of the right cyclins.
- during the cell cycle, the concentration of various cyclins increase and decrease during specific stages.
- cyclins bind to CDKs creating an active CDK-cyclin complex.
- this complex can phosphorylate TFs that will then promote transcription of genes for the next cycle
118
what is the mutation of p53 known as?
TP53
119
what are the two classes of cancer causing genes?
oncogenes and tumor suppressor genes
120
oncogenes
genes that when mutated, actively promote cell division
121
tumor suppressor genes
when mutated lose their ability to regulate or arrest the cell cycle
122
metastasis
damaged cells and cancer cells reaching other tissues and cells through blood and/or lymphatic system
123
what cell type undergo mitosis?
somatic cells
124
prophase stage
- condensation of chromatin into chromosomes
- centrioles pairs separate toward opp poles of the cell
- cylindrical organelles are located outside the nucleus in a region known as centrosome
- once centrioles migrate to opposite poles of the cell, they begin to form spindle fibres
- each fibre radiates outward from the centrioles
- microtubules form asters to anchor the centrioles of the cell membrane
- nuclear membrane dissolves
- nuclei becomes distinct and may disappear completely.
- Kinetochores are protein structure located on the centromeres that serve as an attachment point for specific fibers of the spindle apparatus
125
role of centrosome
responsible for the correct division of DNA
126
metaphase stage
- centrioles pairs are now at opposite ends of the cell
- kinetochore fibers interact with the fibers of the spindle apparatus to align the chromosomes at the metaphase plate
127
what is the metaphase also known as?
equatorial plate
128
anaphase stage
- the centromers split so each chromatid has its own centromere
- shortening of the kinetochore fibers
129
Telophase
- reverse of prophase
- spindle apparatus disappears
- nuclear membrane reforms
- nuclei appears
- chromosome uncoil
130
cytokinesis
seperation of the cytoplasm and organelles giving each daughter cell enough material to survive on its own
131
range of cell division in somatic cells?
20-50
132
what chromosome can the ova carry? what about sperm?
ova: x chromosome
sperm: either x or y
133
what are males termed as when discussing the x and y chromosomes?
hemizygous since one copy of the X chromosome
134
what are females termed as when discussing the x chromosomes?
homozygous or heterozygous
135
are sex disorders with respect to X chromosome more common in males or females? why
males since only one copy of X chromosome
136
what is one notable region on the Y chromosome?
SRY (sex determining region Y) which codes for the transcription factor that initiates testis differentiation and the formation of male gonads
137
germ cells are also known as?
gametocytes
138
daughter cells after meiosis are known as?
gametes
139
how are replication and division different in mitosis vs meiosis? (simple answer)
mitosis consists of one round of each replication and division
meiosis consists of one round of replication followed by two rounds of division.
140
what is the result of meiosis 1? what about meiosis 2?
meiosis 1: the result in homologous chromosomes being separated
meiosis 2: (similar to mitosis), it results in the separation of sister chromatids without a change in ploidy
141
2n vs n:
in mitosis, the start with ___ and end with ___
in meiosis 1, the start with ___ and end with ___
in meiosis 2, the start with ___ and end with ___
in mitosis, the start with 2n and end with 2n
in meiosis 1, the start with 2n and end with 2n
in meiosis 2, the start with 2n and end with n
142
meiosis 1 is also known as
reductional division
143
meiosis 2 is also known as
equational division
144
how many homologous pairs a human genome composed of?
23 homologous pairs
145
what are homologous pairs?
separate chromosomes sych as maternal and paternal
146
chromatid vs homologous pairs vs chromosomes
92 chromatids organized into 46 chromosomes, which is organized into 23 homologous pairs
147
explain prophase 1: ensure you highlight the difference compared to mitosis
- chromatin condenses into chromosomes
- spindle fiber forms
- nuclei and nuclear membrane disappear
- MAJOR DIFFERENCE: homologous chromosomes come together and intertwine in a process called synapsis - where each chromosome consists of two sister chromatids, therefore, each synaptic pair contains FOUR chromatids and is referred to as tetrad
148
how are homologous pairs held together during prophase 1?
synaptonemal complex
149
define chiasma, it is followed by another process, what is it?
chromatids of homologous chromosomes may break at some point of contact during prophase 1and exchange equivalent pieces of DNA which is known as crossing over
150
does crossing over happen between sister chromatids of the same chromosome?
NO! between homologous chromosomes
151
define recombination in respect to prophase 1
unlink linked genes leading to increased variety of genetic combinations that can be produced via gametogenesis
152
result of crossing over?
each daughter cell will have a unique pool of alleles from random mixture of maternal and paternal
153
which Mendel's law can crossing over explain?
second law - law of independent assortment! and that is the inheritance of one allele is INdependent of the inheritance of any other
154
explain Metaphase 1: highlight any differences with mitosis
- homologous pairs (tetrad) line at the metaphase plate
- each pair of homologous pairs attaches to separate spindle fiber by kinetochore
- DIFFERENCE: in mitosis each chromosome is lined up on the metaphase by two spindle fibers while in meiosis, homologous chromosomes are lined up from each other at the metaphase plate by one spindle fiber
155
Explain Anaphase 1: highlight any differences with mitosis
- homologous pairs separate and are pulled to opposite poles of the cell via disjunction
156
disjunction when discussing meiosis?
the separation and pulling of homologous pairs during anaphase 1, where each chromosome of paternal origin separates or disjoins from its homologue of maternal origin
157
segregation in meiosis?
seperation of two homologous chromosomes
158
which law of Mendel is anaphase 1 related to?
first law of segregation!
159
explain telophase 1: highlight any differences with mitosis
- nuclear membrane forms around each new nucleus
- each chromosome consists of two sister chromatids joined at the centromere
- cells are haploid (only n chromosomes are found in each daughter cell)
160
interkinesis or short period?
occurs between cell division in meiosis 1 (telophase 1), during which chromosomes partially uncoil
161
where does reductional division occur?
in meiosis 1 where the chromosome number is halved and the daughter cells have the haploid number of chromosomes (23 chromosomes)
162
how many chromosomes at the end of mitosis? meiosis 1? meiosis 2? in EACH daughter cell
mitosis: end with 46 chromosomes each (no change)
meiosis 1: end with 23 chromosomes each
meiosis 2: end with 23 chromosomes each (no change)
163
substances that cause mutations are called:
mutages
164
if the transposon inserts in the middle of a coding sequence __________
the mutation will disrupt the gene
165
basic examples of what could result in derangements of the normal amino acid sequence?
incorrect pairing of nucleotides during transcription or translation or tRNA molecule charged with the incorrect amino acid for its anticodon.
166
point mutations
occur when one nucleotide in DNA is swapped for another.
subcategorized into:
- silent
- missense
- nonsense mutations
167
compare and contrast between silent vs missense vs nonsense mutations
- silent: a change in the nucleotide does not affect the final protein synthesized from the gene. Occurs when the changed nucleotide is transcribe to be the third nucleotide in a codon because there is degeneracy (wobble) in the genetic code
- missense: when the change in nucleotide results in substituting one amino acid for another in the final protein
- nonsense: when the change in nucleotide results in substituting a stop codon for an amino acid in the final protein
168
frame - shift mutations
occurs when nucleotides are inserted into or deleted from the genome
usually resulting in either changes in the amino acid sequence or premature truncation of the protein
169
what are the types of frame-shift mutations
insertions or deletion mutations
170
chromosomal mutations
larger scale mutations in which large segments of DNA are affected
171
deletion mutations
occurs when a large segment of DNA is lost from a chromosome
172
Duplication mutations
occurs when a segment of DNA is copies multiple times in the genome
173
inversion mutations
occurs when a segment of DNA is reversed within the chromosome
174
insertions mutations
occurs when a segment of DNA is moved from one chromosome to another --> frameshift
175
translocation mutations
occurs when a segment of DNA from one chromosome is swapped with a segment of DNA form another chromosome
176
examples of how mutations can be advantageous?
sickle cell disease is a single nucleotide mutation that causes sickled hemoglobin --> heterozygotes for sickle cell disease have minor symptoms, and have natural resistance to malaria because their red blood cells have a slightly shorter lifespan.
Therefore, heterozygous sickle cell disease have a selective advantage because they are less likely to die from malaria
177
example of deleterious mutations
Patients with XP, DNA that has been damaged by IV radiation cannot be repaired appropriately. It can introduce cancer-causing mutations --> lack repair mechanism, so patients with CP are frequently diagnosed with malignancies
178
example of inborn errors of metabolism
people lacking the enzyme phenylalanine hydrolase that completes the metabolism of the amino acid phenylalanine, will have accumulation of toxic metabolites of phenylalanine which causes seizures, impairment of cerebral function and learning disabilities
179
Genetic linkage
a flow of genes between species
180
what is a hybrid offspring? give an example
individuals from different but closely related species mate and produce a hybrid offspring such as a mule (hybrid of a male horse and female donkey).
181
can hybrid offsprings produce?
they cannot reproduce because they have an odd number of chromosomes (63 chromosomes) and cannot undergo normal homologous pairing in meiosis and cannot form gametes.
182
Genetic drift
changes in the composition of the gene pool due to chance - especially in small population
183
The founder effect
a more extreme case of genetic drift in which a small population of a species finds itself in reproductive isolation from other populations as a result of natural barrier and catastrophic events or other bottlenecks
184
bottlenecks
drastically and suddenly reduce the size of the population available fro breeding
185
impact on genetic diversity by inbreeding, founder effect, and genetic drift?
inbreeding, founder effect, and genetic drift cause reduction in genetic diversity which is the reason why a small population may have increased prevalence of certain traits and diseases
186
inbreeding
mating between genetically related individuals
187
inbreeding depression
the loss of genetic variation may cause reduced fitness of the population --> inbreeding depression
188
outbreeding or outcrossing
the introduction of unrelated individuals into a breeding group --> increased variation within a gene pool and increase fitness of the population
189
genes are organized into ______ to ensure that genetic material is passed easily to daughter cells during mitosis and meiosis
chromosomes
190
genes have alternative forms that are known as ___
alleles
191
the genetic combination possessed by an individual is ______ and the manifestation of a given phenotype is known as ______
the genetic combination possessed by an individual is GENOTYPE and the manifestation of a given phenotype is known as PHENOTYPE
192
Humans posses two copies of each chromosome called ______.
homologues
193
are there any exceptions to homologues chromosomes?
yes!
sex chromosomes of genotypical males who have on X chromosome and one Y chromosome
194
how many alleles will a person inherit for all genes?
two alleles
195
humans inherit two alleles for all genes, is there any exceptions?
yes! male sex chromosomes
196
homozygous vs heterozygous geneotype vs hemizgyous
homozygous: both alleles are the same for a given gene
heterozygous: alleles are different
hemizygous: describes a situation in which only one allele is present for a given gene
197
example of hemizgyous
one X chromosome in males
198
complete dominance
when only one dominant and one recessive allele exists for a given gene
the presence of one dominant will mask the presence of recessive
199
codominance
when more than one dominant allele exists for a given gene
200
example of codominance in humans
a person with the type A allele and type B allele will have a type AB blood type
201
incomplete dominance
occurs when the heterozygote expresses a phenotype that is intermediate between the two homozygous genotypes
202
example of incomplete dominance
mating of certain flowers in which a red flower is crossed with a while flower results in pink flowers
203
penetrance
the proportion of the population with a given genotype who actually express the phenotype
204
expressivity
the different manifestations of the same genotype across the population
205
consider Huntington's disease:
individuals with more than 40 sequence repeats have ___ penetrance, individuals with fewer sequence repeats show _____ penetrance, and people with very few sequence repeats have ____ penetrance
individuals with more than 40 sequence repeats have FULL penetrance, individuals with fewer sequence repeats show HIGH penetrance, and people with very few sequence repeats have REDUCED/LOW/NON penetrance
206
constant vs variable expressivity
constant: all the individuals with a given genotype express the SAME phenotype
variable: individuals with the same genotype may have different phenotypes
207
neurofibromatosis type 2 has a range of phenotypes ranging from no clinical effect to sever disability, this is an example of_____
expressivity
208
Mendel's first law
Law of Segregation
- genes exist in alternative forms (alleles)
- an organism has two alleles for each gene (one inherited from each parent)
- the two alleles segregate during meiosis resulting in gametes that carry only one allele for any inherited trait
- if the two alleles of an organism are different, only one will be fully expressed and the other will be silent (expressed one is the dominant)
209
with which phase of meiosis does Mendel's first law correlate with?
Anaphase I
by separating these chromosome into different cells, each gamete carries only one allele for any given trait
210
Mendel's second law
law of independent assortment
- inheritance of one gene does not affect the inheritance of another gene
211
which phase of meiosis explains Mendel's second law?
The spermatogonia and oogonia undergo genome replication before meiosis I.
The daughter DNA strand is held to the parent strand at the centromere (forming sister chromatids)
During prophase I, homologous chromosomes pair up to form tetrads (four chromatids involved)
small segments of genetic material are swapped between chromatids in homologous chromosomes, resulting in novel combinations of alleles that are NOT PRESENT IN THE ORIGINAL CHROMOSOME (recombination).
Allowing for inheritance of one gene to be INDEPENDENT of the inheritance of all others
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Griffth Work. Which principle does he explain?
He worked with virulent S. pneumonia (with smoother capsule) and avirulent (no smooth capsule).
When he injected the mice with virulent type, the mice died.
When he injected the mice with avirulent type, the mice survived.
He decided to mix the living avirulent type with nonliving avirulent type, and injected it into the mice --> the mice lived!!
He theorized that the live avirulent must have acquired the ability to form smooth capsules from the dead virulent
Transforming principle
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Avery, MacLeord and McCarty work
Worked with S. pneumonia
They learned from Griffith that nonvirulent bacteria was able to kill the mice when mixed with dead virulent type.
They decided to treat the substance with enzymes known to degrade the DNA, and the bacteria did NOT transform and the mice LIVED!
When treated with an enzyme to degrade the protein, the mice DIED.
Concluded it must be DNA the transforming substance
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Hershey and Chase
They wanted to confirm if DNA independently carries genetic information
they created a bacteriophage with radio-labelled DNA and protein. One group has radio-active S and the other radio-active P.
After the bacteriophage, they found only P radio-label entered the cells --> DNA!
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Epigenetic
a general term for changes in DNA that do not involve an alteration to the nucleotide sequence
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impact of methylation of DNA promoter regions
tends to decrease the expression of specific genes
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imprinting
an epigenetic process in which gene expression is determined by the contributing parent
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How is Prader Willi syndrome an example of imprinting?
Chromosome 15
if the deletion of this region of the chromosome occurs on the parental chromosome and the maternal copy is heavily methylated, it leads to Prader Willi syndrome
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Angelman syndrome
deletion of the same region on the maternal chromosome and paternal methylation leads to this disease (imprinting example)
220
explain natural selection. What is it sometimes referred to?
AKA: survival of the fittest
Certain characteristics or traits possessed by individuals within a species may help those individuals have a greater reproductive success --> passing those traits to offsprings
221
What are some basic tenets Darwin's theory was built on?
- organisms produce offspring, few of which survive to reproductive maturity
- chance variations within individuals in a population may be heritable
- individuals with a greater preponderance of these favourable variations are more likely to survive to reproductive age and produce offspring
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when are variations said to be favourable?
if the variations given an organism a slight survival advantage
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the level of reproductive success is termed ___
fitness
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Darwin's theory on mutations or recombination
when mutation or recombination results in a change that is FAVOURABLE to the organism's reproductive success, that change is more likely to pass on to the next generation ( the opposite is also true)
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What is the term for:
when mutation or recombination results in a change that is FAVOURABLE to the organism's reproductive success, that change is more likely to pass on to the next generation ( the opposite is also true)
differential reproduction
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Why do traits passed on by the more successful species become ubiquitous in gene pool?
because gene pool changes over time!
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do individuals evolve over time?
NO!
populations evolve over time
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Inclusive fitness
a measure of an organism's success in the population, based on the number of offspring, success in supporting offspring, and the ability of the offspring to then support others
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inclusive fitness and altruistic behaviour
inclusive fitness promotes that altruistic behaviour can improve the fitness and success of a species as a whole
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punctuated equilibrium
contrast to Darwin's theory
Changes in some species occur in rapid bursts rather than evenly over time
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molecular clock model
the more similar the genomes, the more recently the two species separated from each other
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As species become more taxonomically distant, the proportion of shared genome will ______
decrease
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Rate of evolution if species live in rapidly changing environment
Rate of evolution will be greater as selection for and against certain traits will be actively occurring within that population
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if a species is already perfectly suited to its habitat, and there are no changes to the conditions in which they live in, the rate of evolution will be _____
exceedingly slow
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how is the rate of evolution measured?
measured by the rate of change of a genotype over a period of time and is related to the severity of the evolutionary pressures on the species
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Divergent evolution
the independent development of dissimilar characteristics in two or more lineages sharing a common ancestor
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identify the type of evolution
Cats are both mammals in the order Carnivora, yet they differ markedly in general appearance. They live in different environments and adapted to different selection pressures while evolving
divergent evolution
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Parallel evolution
the process whereby related species evolve in similar ways for a long period of time in response to analogous environmental selection pressure
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Convergent Evolution
The independent development of similar characteristics in two or more lineages not sharing a recent common ancestor
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Identify the type of evolution
Fish and Dolphins belong to different classes of vertebrates but evolved to live in the same features (aquatic life)
Convergent Evolution
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species
the largest group of organisms capable of breeding to form fertile offspring
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Speciation
the formation of new species through evolution
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isolation
the progeny of populations could freely interbred
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example of isolation and interbreeding
if we took two populations of the same species and isolated them geographically for a long period of time, different evolutionary pressures would lead to different adaptive changes ---> those can interbreed
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prezygotic mechanisms
prevent the formation of the zygote completely
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postzygotic mechanism
allow the fate fusion but yield either nonviable or sterile offspring
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temporal isolation, ecological isolation, behavioural isolation, reproductive isolation or gametic isolation are examples of
prezygotic mechanism
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hybrid sterility, hybrid inviability and hybrid breakdown are examples of
postzygotic mechanism
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define each:
temporal isolation
ecological isolation
behavioural isolation
reproductive isolation
gametic isolation
temporal isolation
ecological isolation
behavioural isolation
reproductive isolation
gametic isolation
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define each:
hybrid sterility
hybrid inviability
hybrid breakdown
hybrid sterility
hybrid inviability
hybrid breakdown
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niche
a specific environment including habitat, available resources, and predators, for which species specifically adapted
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adaptive radiation
related to the concept that describes the rapid rise of a number of different species from a common ancestor
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benefit of adaptive radiation
it allows various species to occupy different niches
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polymorphism
naturally occurring differences in form between members of the same population, such as light and dark coloration in the same species of butterfly
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disruptive selection
two extreme phenotypes are selected over time
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famous example of disruptive selection
Darwin noticed birds have large OR small finches, NO MEDIUM. He believes large finches for large seeds and small finches for small seeds, and they will be selected for.
He believes seeds size led to the effect of small or large finches
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directional selection
adaptive pressure can lead to the emergence and dominance of initially extreme phenotype through directional selection
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colonies that have the resistance gene survive on an antibiotic plate is an example of which natural selection?
directional
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stabilizing selection
keeps phenotypes within a specific range by selecting against extremes
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example of stabilizing selection
human birth weight is maintained within a narrow band by stabilizing selection
- overweight fetuses --> health problems
- underwright fetuses --> health problems
weight within a narrow band -->healthy
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list the types of natural selection
stabilizing
directional
disrupted
262
list patterns of evolution
divergent
parallel
convergent
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allele frequency
how often an allele appears in a population is known as its allele frequency
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what is meant by
" allele frequency of P is 75/100"
Does NOT mean which flowers contain the allele or if those flowers are homozygous or heterozygous, it only tells us the representation of the allele across ALL chromosomes in the population
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What can we say about the gene pool, if the frequency is not changing?
Gene pool is stable and evolution is not occurring
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When can we a population is at Hardy Weinberg equilibrium?
if:
- the population is very large
- no genetic drift
- no mutations that affect the gene pool
- mating between individuals is RANDOM
- no sexual selection
- no immigration of individuals into or out of the population
- genes in the population are all equally successful at being reproduced
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what are the two Hardy Weinberg equations?
p + q = 1
p^2 + 2pq + q^2 = 1
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if we say that a population is at Hardy Weinberg equilibrium, what is happening with evolution?
NO EVOLUTION IN THE POPULATION
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difference between:
p + q = 1
p^2 + 2pq + q^2 = 1
p + q = 1
tells us about the alleles in the population
p^2 + 2pq + q^2 = 1
provides us information about the frequency of genotypes and phenotypes in the population
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a cross in which only one trait is being studied is said to be:
monohybrid
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how are ratios calculated phenotypically and genotypically
Phenotypic:
Dominance:recessive
Genotypic:
Homozygous dominance:heterozygous dominance:homozygous recessive
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what is a test cross or a back crosses? when is it used?
used to determine the unknown genotype (parent) based on the offspring phenotype
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pp x P?
Let's say all of the offspring are of the dominant phenotype, what can we say about the unknown genotype?
the unknown must be HOMOzygous dominant
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pp x P?
Let's say the offspring give the phenotype ratio to be 1:1, what can we say about the unknown genotype?
the unknown must be HTEREOzygous
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Hemophilia is a sex linked trait (disease).
is it possible for males to be carriers? what about females?
it is NOT possible for males to be carriers, they can either be NORMAL OR AFFECTED since they have only one X chromosome.
Females on the other hand have two chromosomes and as a result can be affected, normal or carriers
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location of genes and crossing over
genes that are CLOSE to one another are less likely to be crossed over. Therefore, the further apart they are, the more likely it is that there will be a point of crossing over between them
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the further apart genes are, the more likely it is that there will be a point of crossing over, and this is called?
chiasma
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the likelihood that two alleles are separated from each other during crossing over is called?
recombination frequency
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recombination frequency and distance relationship
they are directly proportional to one another
280
what is a genetic map used for?
to represent the relative distance between genes on a chromosome can be constructed
281
one map unit or centimorgan corresponds to ____ chance of recombination between two genes
1
282
If two genes were 25 map units apart, we would expect __ percent of the total gametes examined to show recombination somewhere between these two genes
25
283
where are the lungs located?
thoracic cavity
284
pathway of air entrance
nares of the nose --> nasal cavity --> pharynx --> larynx --> trachea --> bronchi --> alveoli
285
what filters the air that goes into the nasal cavity?
by mucous membranes and nasal hairs (vibrissae)
286
where is the phyrnax located?
resides behind the nasal cavity and at the back of the mouth
287
where is the lyrnax located?
below the pharnyx
288
how is food kept away from the respiratory tract?
the openning of the larynx (glottis) is covered by epiglottis during swallowing
289
what is the surface area of the alveoli?
100 m^2
290
_____ forms a closed sac against which the lung expands
pleura
291
the surface adjacent to the lung is ____ and the outer part is ______
the surface adjacent to the lung is visceral pleura and the outer part is parietal pleura
292
do our lungs fill passively?
no! they require skeletal muscles to generate negative pressure for expansion
293
describe the diaphram
thin, muscular muscle, and divides the thoracic cavity from the abdominal cavity
294
the diaphram is under ___ control even tho our breathing is under ____ control
the diaphram is under SOMATIC control even tho our breathing is under AUTONOMIC control
295
The space within the sac is referred to ____
intrapleural space
296
inhalation muscles
diaphragm and external intercostal muscles
297
what happens to the intrathoracic volume as we breathe?
increases
298
what happens to the intrapleural pressure as we breathe?
decreases
299
inhalation is a _____ pressure breathing
negative
300
muscles of exhalation
internal intercostal muscles and abdominal muscles
301
the diaphragm is ___ during inhalation
flate
302
____ disease characterized by the desctruction of the alveolar walls --> reduction in elastic recoil of the lungs making the process of _____ difficult
EMPHYSEMA disease characterized by the desctruction of the alveolar walls --> reduction in elastic recoil of the lungs making the process of EXHALATION difficult
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When the lungs recoil, their volume becomes _____ and the pressure _____
When the lungs recoil, their volume becomes SMALLER and the pressure INCREASES
304
what can't the spirometer measure?
cannot measure the amount of remaining air in the lungs after complete exhalation
305
______ the maximum volume of air in the lungs when one inhales completely, and is usually between ______
TLC - total lung capacity
6-7 L
306
______ the volume of additional air that can be forcibly inhaled after a normal inhalation
IRV - inspiratory reserve volume
307
_____ The volume of additional air that can be forcibly exhaled after a normal exhalation
ERV - expiratory reserve volume
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____ the volume of air inhaled or exhaled in a normal breath
TV - tidal volume
309
_____ the volume of air remaining in the lungs when one exhales completely
RV - residual volume
310
_____ the difference between the minimum and maximum volume of air in the lungs
VC - vital capacity
311
how is vital capacity calculated?
TLC - RV
312
collection of neuron in the medulla oblongata called ______
ventilation center
313
how does the ventilation center fire?
fires rythmically to cause regular contraction of respiratory muscles
314
what responds to CO2 levels? explain
chemoreceptors in neurons responds to CO2 concentration.
As the partial pressure of CO2 in the blood rises --> respiratory rate will increase so that more CO2 is exhalled --> dropping CO2 level
315
do chemoreceptors respond to O2?
Yes! during low oxygen concentration
316
respiration response to high CO2?
high: hyperventilation --> lowers CO2
317
hypoxemia
low oxygen levels
318
hypercarbia
high CO2
319
hypercapnia
high CO2
320
pulmonary viens vs pulmonary artieries
capillaries bring deoxygenated blood from the pulmonary artery which orginated from the right ventricle of the heart
the oxygenated blood returns to the right atrium from the pulmoary vein
321
how would our respiratory system adjust if we moved to a higher altitudes where less oxygen is available?
- we would breathe more rapidly to try to avoid hypoxia
- the binding of hemoglobin to oxygen would be altered to facilitate the UNLOADING of oxygen at the tissues
322
how would the natural hemoglobin respond to low CO2?
DECREASE the unloading of oxygen to tissues
323
what regulates heat?
regulated by vasodilation and vasoconstriction
324
what happens to thermal energy as cappilaries expand? contract?
expand: more blood passes through the vessels and larger amount of thermal energy can be dissipated (lost)
contract: less blood passes through the vesseles conserving thermal energy
325
function of lysozomes in nasal cavity
able to attack the peptidoglycan walls of gram positive bacteria
326
mucociliary escalator
the internal airways are lined up with mucus, which traps particular matter and larger invaders. underlying cilia then propel the mucus up the respiratory tract to the oral cavity, where it can be expelled or swallowed
327
bicarbonate buffer system equation
CO2 + H20 -->/<-- H2CO3 -->/<-- H+ + HCO3-
328
body normal pH
7.35 - 7.45
329
respiratory response to low pH
CO2 + H20 -->/<-- H2CO3 -->/<-- H+ + HCO3-
LOW: hydrogen ions are higher than usual --> acid-sending chemoreceptors send signals to the brain --> increase the respiratory rate --> an increase in the H+ will cause a shift in the bicarbonate system to the LEFT
As the respiratory rate increases --> more CO2 is blown off --> reaction will also be pushed to the LEFT
330
respiratory response to pH
CO2 + H20 -->/<-- H2CO3 -->/<-- H+ + HCO3-
HIGH: blood too basic --> body will increase acidity --> more CO2 will be retained --> shift the reaction to the RIGHT --> more H+ produced and bicarbonate ions --> lowers the pH
331
alkalemia
basic blood
332
acidemia
acidic blood
333
metabolic acidosis
excess acid by an mechanism besides hypoventilation
334
weak vs strong acid/base
H+ vs HCO3-
H+ : strong acid
HCO3-: weak base
335
what happens to each of the following at rest?
Patm
Palv
Pip
Ptp
Ptw
Patm = 0
Palv = 0 --> no air flow
Pip = -5 --> must be negative or else pneumothorax
Ptp = 0-(-5) = 5 --> positive to avoid collapse
Ptw -5-(0) = -5
336
what happens to each of the following at on set of inspiration?
Patm
Palv
Pip
Ptp
Ptw
Patm = 0
Palv = -1 --> air flow
Pip = -6
Ptp = -1-(-6) = 5
Ptw -6-(0) = -6
337
what happens to each of the following at the end of inspiration?
Patm
Palv
Pip
Ptp
Ptw
Patm = 0
Palv = 0 --> no air flow
Pip = -8
Ptp = -0-(-8) = 8
Ptw -8-(0) = -8
338
what happens to each of the following at one set of expiration?
Patm
Palv
Pip
Ptp
Ptw
Patm = 0
Palv = +1 --> air flow
Pip = -7
Ptp = +1-(-7) = 8
Ptw -7-(0) = -7
339
how is Ptw calculated? Ptp?
Ptw = Pip - Patm
Ptp = Palv - Pip
340
transpulmonary pressure is also the
recoil pressure
341
pleural/intrapleural pressure is related to the ___ pressure
intrathoracic
