bio 1 Flashcards
1
Q
where is non nuclear DNA found? What are characteristics of it?
A
in mitochondria (mitochondrial DNA) . - haploid, from maternal copy - circular - helical -
2
Q
what is the nucleolus?
A
site of rRNA transcription and ribosome assembly.
3
Q
What is the rough ER?
A
ribosome covered ER that translocates proteins into the ER lumen to be translated.
-proteins from RER are bound to the ER itself, the golgi, the lysosome, the endosome, the plasma membrane or some to be secreted outside the cell
4
Q
What is the smooth ER?
A
ER with no ribosomes- regulates and releases calcium ions and processes toxins + Lipid synthesis/ modifications NOT metabolization.
5
Q
What is the golgi apparatus function?
A
cellular post office for protein; organize and continue post translational modifications, excrete vesicles bound for plasma membrane back to ER or to organelles.
6
Q
What is the structure of the mitochondrion and function?
A
outer mitochondrial membrane- separates content of the mitochondrion from he rest of the cell and creates compartment with ideal conditions for aerobic respiration.
inter membrane space (between outer an inner membrane)- where protons are pumped by ETC- high proton concentration can easily be formed in chemiosomosis.
inner membrane space- contains electron transport chains and ATP synthase that carry out oxidative phosphorylation.
Cristae- tubular or shel like projections of inner membrane which increases available surface area for oxidative phosphorylation.
Matrix- fluid inside the mitochondrion contains enzymes for the Krebs cycle and the link reaction.
7
Q
What does the endosymbiotic theory suggest?
A
mitochondria evolved form aerobic prokaryotes that were engulfed by larger host prokaryotes.
Evidence include: The presence of the double bilayer membrane, the fact that mitochondria have their own DNA, that they replicate their own DNA, and that they divide and replicate much like a bacterium
8
Q
How do the pH values of the matrix and the inter membrane space compare?
A
the intermembrane space will be more acidic (lower pH) because of the hydrogen ion gradient across the inner mitochondrial membrane.
9
Q
Predict the consequences of the insertion of hydrogen channels within either of the two mitochondrial membranes.
A
alternate pathway for their passageway back into the matrix (down their concentration and charge gradient) other than through the ATP synthase. This would decrease the production of ATP.
10
Q
What is the role of the lysosomes?
A
pH5- digest cell parts and fuse with phagocytotic vesicles + can participate in cell death
11
Q
What are peroxisomes?
A
Self replicating organelle that detoxify chemicals and participates in lipid metabolism.
12
Q
1) A lab worker must inject a segment of DNA into the nucleus of a living cell. To access the nuclear lumen, the microscopic needle must pierce a minimum of how many layers of lipid membrane?
A) 2 B) 3 C) 4 D) 6
A
D) cell membrane (2), plus the outer nuclear membrane (2), plus the inner nuclear membrane (2), for a total of six single layers of lipids-
13
Q
What are microtubules made of?
A
Tubulin; alpha and beta which forms a heterodimer that assembles into a long chain of protofilaments.
13 protofilament surrounding one hollow core = one microtubule
14
Q
What is the 9+2 arrangement?
A
found only in eukaryotic cilia and flagella. The “9” and “2” refer to nine doublets (two microtubules each) surrounding a center doublet (2 microtubules) in a wheel-like design. That would be a total of 20 microtubules—each one of those twenty microtubules being the hollow tube of 13 protofilaments just described.
15
Q
What is the cytoskeleton made of?
A
scaffolding like network of microfilaments, microtubules and intermediate filaments that provides structure to the cell and creates a highway of sorts for intracellular transport.
16
Q
what are intermediate filaments?
A
proteins that polymerize to form filaments that are intermediate in diameter.
- Strength and structure
- Lamins and keratin
- Protect from shear stress
- Tend to be more structurally stable/ stronger filaments
- Organization and interaction
17
Q
what are microfilaments?
A
proteins monomers (like actin) polymerize to form microfilaments and form the thin portion of sarcomere.
○ Gives cells their shape
○ Cell motility
18
Q
what are thick filaments?
A
- microtubules
- Position organelles
- Direct transport
- Cilia and flagella= specialized cells for movement.
19
Q
What is the difference between Flagella and cilia?
A
Flagella are whip-like projections from the cell body used for locomotion. In humans, sperm cells are the only cells that have flagella.
Cilia are similar protrusions found on the lumen-facing side of many epithelial cells lining various cavities in the body. In humans cilia are found in the lungs, ependymal cells of nervous system, and reproductive system.
20
Q
Do all cilias contain microtubules? in flagella of sperm? in cells part of cytoskeleton? in spindle apparatus?
A
Yes to all
21
Q
What problems would a disease that prevented microtubule production cause?
A
- weakened cytoskeleton
- weakened organelle motility/ transportation
- inability to complete metaphase of meiosis.
22
Q
What are phospholipids
A
Phospholipids are lipid molecules with non-polar tail regions and a polar phosphate heads. This polarity is pivotal to their function in membranes.
- formed by combining a glycerol molecule with two fatty acids and one phosphate.
-
23
Q
what are integral proteins?
A
proteins that have one or more moieties (i.e., segments) embedded within the phospholipid bilayer.
24
Q
what are surface proteins?
A
aka peripheral proteins that do not enter the hydrophobic core but are contained entirely on the polar surface of the membrane.
25
what are transport proteins?
integral proteins that span the entire width of the bilayer membrane, creating tunnels for the passage of ions, proteins or other substances through hydrophobic core.
26
What's a membrane receptor ?
A membrane receptor is any protein that specifically binds a signaling molecule to initiate a cellular response.
27
what's cholesterol?
an amphipathic (hydrophilic and phobic) molecule with a steroid region and a polar region. It's part of the fluid mosaic model of the plasma membrane.
28
How does high temperature affect cholesterol in the plasma membrane?
higher temperature around physiological temperature (37C), the non polar region (steroid region) interacts with the hydrophobic tail of the phospholipids of the plasma membrane and holds them in place---> increases rigidity.
29
How does lower temperature affect cholesterol in the plasma membrane?
he interactions between the non-polar tails could cause crystallization, the presence of the rigid steroid portion of cholesterol disrupts Van der Waals forces between fatty acid tails maintaining a minimum level of fluidity. --> makes it more fluid
30
What are the four types of membrane transport?
1) simple diffusion - no ATP
2) facilitated diffusion- no ATP (ex: osmosis)
3) Active transport (ATP Required) --> required to move something against its concentration gradient.
4) Secondary active transport --> no direct coupling of ATP required.
31
what are tight junctions?
limit passage of molecules and ions through the space between cells- Water proof barriers. Most often found in epidermis of the skin
32
What are gap junctions?
Tunnels between adjacent cells, allowing exchange between cytoplasm of cells.
ex: in heart cells
33
what are adherent junctions?
cell to cell junctions that keep cells together with cadherins.
--> prominent in actin cytoskeleton
34
What are desmosomes?
another type of cell-to cell junctions that attaches cells together.
Has intermediate filament, adhesion proteins (cadherins!) and anchor proteins.
35
How do cell communicate?
1) Endocrine- long distance signaling through hormones.
2) paracrine: local area signaling
3) autocrine: signal received by same cell that secreted it.
4) intracrine: intrasignaling within same cell
5) juxtacrine: contact dependent signaling
6) nervous system: synapses
36
What type of receptors are steroids?
intracellular receptors
37
What's the general pathway of G proteins?
signal --> receptor --> G protein alpha and Beta unit--> GTP bind --> alpha unit dissociates and acts as agonist for another enzyme like adenylyl cyclase --> catalyzes conversion of cAMP through ATP to stimulate PKA production
38
in the cell cycle, what is G0?
non proliferative- cell arrest and death phase
| fully differentiated. neurons and cardiac muscle cells are frozen in G0 and do not divide
39
in the cell cycle, what is G1?
Growth phase of cell- phase most active cells live and function
40
in the cell cycle, what is S?
DNA is replicated
41
in the cell cycle, what is G2?
Follows S phase and features continues cell growth and high metabolic activity- more dan replicated
42
what's M phase?
mitotic division
43
what's chromosome number ? haploid chromosome number ?
46; 23
44
what does mitosis yield?
2 genetically identical diploid daughter
45
what happens during prophase of mitosis?
During prophase, the nuclear membrane degenerates and the chromosomes condense.
46
what happens during metaphase of mitosis?
Metaphase is indicated by the chromosomes lining up at the metaphase plate and formation of the spindle apparatus.
47
what happens during anaphase of mitosis?
Anaphase is indicated by separation of the chromosomes and migration toward the opposite poles of the cell.
48
what happens during telophase of mitosis?
Telophase is indicated by the nuclear membranes beginning to re-form and the chromosomes unwinding.
49
what happens during interphase of mitosis?
resting phase between successive mitotic divisions of a cell, or between the first and second divisions of meiosis.
50
How are the cell cycle phases of meiosis (I and II) different from those in mitosis?
They are basically the same except crossing over happens during metaphase of meiosis and meiosis I yields two daughter cells with two homologs.
These two daughter cells then further divide into four daughter cells the are not genetically identical and each has one chromosome (n chromosome) while mitosis has 2n chromosomes.
51
What is chromosome nondisjunction and when does it occur?
Nondisjunction results in an unequal number of chromosomes in the daughter cells and happens during anaphase of meiosis I or II.
extra chromosome - tiresome
52
When does crossing over occur and why?
during meiosis I.
| important because it breeds diverse beings and helps our species survive during natural selection
53
What is the yield of meiosis?
4 genetically distinct haploid daughters cells.
| centromere splits during meiosis II.
54
2) A karyotype is somewhat like a photographic list of all of the chromosomes found in a cell. If homologous pairs are present, they appear next to one another on the exposed film. All of the chromosomes for the entire cell are presented on the same slide, making differences in the relative length, size and orientation of the chromosomes readily apparent. If a karyotype were produced for a human cell that had just undergone Telophase I of Meiosis, the entire karyotype slide should contain (assume that the chromosomes are still condensed and have not reverted back to chromatin):
A) 23 pairs of homologous chromosomes, all of similar size
B) 46 chromosomes, increasing in size from 1 to 23
C) 92 chromosomes, decreasing in size from 1 to 92
D) 23 chromosomes, decreasing in size from 1 to 23
d
55
what is the structure of a nucleotide? what is it bound to?
1) nucleotide bout to another nucleotide through hydrogen bond.
2) nucleotide bound to deoxyribose sugar- bound to triphosphate through covalent bonds
3) phosphodiester bonds holding phosphate of nucleotide superimposing one another together.
56
What is the story of DNA replication? What are the key players?
1) At Origin of replication. Helices unzips double helix and single strand binding proteins coat the individual strands and prevent them from re-anneling.
2) RNA polymerase construct short RNA primers on both strands. One strand is 5'-3' (okazaki fragment) and the other is 3'-5' (leading strand).
3) DNA polymerase adds complimentary base pair to DNA strands and the sliding clamp helps keep the DNA polymerase tightly associated with strand.
4) RNase H removes all RNA primers.
5) DNa ligase ligates nucleotide bases together by creating the last necessary phosphodiester bonds.
57
what is telomerase?
enzyme that adds length to the telomere.
Constitutively active telomerase can cause cancer by not allowing genes to be shortened with age as they should be and leading to unlimited cell division.
58
What are some causes of DNA damage?
- spontaneous hydrolysis (DNA reacts with external stimuli)
- Damage by External chemicals/ radiation: mutagens
- Mismatched Base pairs: errors during replication or methylation of guanine
59
What are mechanisms of DNA repair?
- proofreading: DNA polymerase dos proofreading and catches mistakes.
- Mismatch repair system: enzymes scan newly formed DNA and locate/ excise and replace mismatch.
- Base excision: base portion ONLy is excised via DNA glycosylase.
- Nucleotide Excision: Excision on oligonucleotide that includes several bases on either side of the error.
60
What is restriction endonuclease?
enzymes that cut DNA at specific pre-determined sequences called recognition sequences.
--> Leaves sticky ends that can be recombined for recombinant DNA.
Sticky ends means one end is longer than other.
61
What is gel electrophoresis used for?
separate molecules of DNA by size.
| smallest molecule travels further
62
What is the point of PCR?
amplify copy/ small segments of DNA. One cop just be know. Use primers, + a DNA polymer ike Taq polymerase and process is done at high temperature (72C) --> creates two new helices and entire process is repeated. The number of copies DOUBLES for each cycle.
63
What is southern blot used for?
verify presence of specific DNA sequence and relative size of DNA fragment.
64
What's northern blot used for?
RNA sequence and relative size of RNA fragment.
65
What's western blot used for?
Protein segments based on relative segment and used with radiolabeled antibodies.
66
what's eastern blot used for?
like western but verify post translational modifications.
67
What are the differences between RNA and DNA?
RNA has a 2' hydroxyl group; DNA does not it's deoxyribose
RNA is single stranded, DNA is double stranded
RNA has uracil base instead of thymine base in DNA.
RNA exits the nucleus into cytoplasm; DNA always stays in the nucleus.
68
What's the difference between rRNA, tRNA and mRNA?
rRNA- ribosomal RNA that act as enzyme to polymerize proteins.
tRNA bridges gap between mRNA and assembly of protein.
mRNA is complimentary RNA strand copied from DNA template strand.
mature mRNA has less non-coding introns and has poly-A tail and 5'cap.
69
what are the terms that refer to the strand of DNA that IS transcribed?
template strand, anti-coding, anti-sense strand.
70
what terms refer to the strand of DNA that is not transcribed/ the complimentary?
sense strand, coding strand.
71
what is the mRNA like?
mRNA is complimentary to the sense strand and exactly like anti-coding EXCEPT that it has U instead of T.
72
What is alternative splicing?
after introns are removed from the mrNA transcript, the eons can be assembled in any number of different orders, each variations result sin different proteins --> diversity in antibodies and proteins for few genes.
73
In the lac operon, we know glucose is inhibiting and lactose is inducing. Would there be transcription if there's
a) glucose, no lactose, b) lactose, no glucose, c) no glucose, no lactose, d) lactose and glucose.
a) no transcription
b) transcription
c) no transcription
d) few transcription
74
In translation, explain initiation, elongation and termination?
Initiation: tRNA binds mRNA
Elongation: translation process (A site --> P site --> E site).
Termination: release factor binds to stop codon and causes dissociation of ribosome complex.
75
What's point mutation?
single base pair substitution
76
What's missense mutation?
a mutation that changes the codon so that different amino acid will be incorporated
77
what's silent mutation?
a mutation that does NOT alter how the amino acid will be incorporated.
78
what's frameshift mutation?
addition/deletion of a nucleotide sot that the reading frame is changed.
79
what's neutral mutation?
mutation that does not negatively impact the premature stop codon.
80
What's the difference between mutations in germ cells and somatic cells?
only germ cells mutations are passed on to offspring
81
What is definition of cancer?
uncontrolled cell division due to failure of cell's normal regulatory mechanisms.
Multiple mutations in tumor suppressor and photo-oncogene are needed for the tumor to be cancerous (malignant).
82
What's the difference between porto-oncogenes and tumor suppressor genes?
Proto-oncogenes: good or normal genes that regulate cell growth and lead to unlimited division when they become mutants.
- one mutation is needed to become mutant.
- gain of function
Tumor suppressor genes help protect the cell from uncontrolled growth. When mutated, those gens are turned off.
- require two recessive alleles to be mutated.
- loss of function
83
3) Assuming no errors during translation, the following segment of mature mRNA should produce a protein with how many amino acids?
5’ AUA ACG ACU AUC GCC AUG CUA AUU CAU GAU GAC AUC AUC CCG CAU GGA AUU CGC UCA AAC GUA UAC CCA GCG CCG UAG AUC CCA GCC ACU UGG GCA AAA AAA 3’
A) 20
B) 21
C) 29
D) 34
A) Look at codons from AUG to UAG (stop codon) but do NOT include UAG = 20
84
What does the law of segregation state?
Alleles segregate independently of one another when forming gametes.
85
What does the law of independent assortment state?
genes located on different chromosomes assort independently.
86
In Punnet square probabilities, if BOTH events occur at the same time, what do you do with the probabilities?
multiply the probabilities of each events occurring individually.
87
In punnet sure probabilities, if EITHEr event occurs, what you do you do with the probabilities?
ADD the probabilities of each event occurring individually.
88
In X linked dominance, what is true of the daughters and sons?
If the mother has X linked dominant mutation then all sons will be affected and daughters may or may not be affected.
If the father has X like dominant - all the daughters will be affected but none of the son.
If it's recessive- daughter will be carriers.
89
What's incomplete dominance? give an example
an expression pattern in which the phenotypes of the dominant and recessive alleles appear to be mixed or blended in the phenotype of a heterozygote. For example, RR may give red flowers, rr white flowers, but Rr gives pink flowers
90
What's co-dominance?
both phenotypes are fully-expressed at the same time in a heterozygote. In the flower example this could mean that RR gives red flowers, rr gives white flowers, and Rr gives red-and-white striped flowers
91
what's incomplete penetrance?
various individuals all have identical genotypes and yet some have the disease phenotype and others do not.
92
what's limited expressivity?
various individuals have the same genotype AND the disease's phenotype. but they are impacted in varying degrees.
ex: missing corpus collosum on the two kids from shadowing .
93
What's pleiotropy?
situation in which one single gene contributes to multiple phenotypic traits.
94
what's mosaicism?
different cells within the same individual contain non identical genotypes
95
What's genetic imprinting?
results when one specific gene is expressed differently depending on which parent it originated from.
96
What's epigenetic?
any heritable phenotype resulting from any process other than a change in the DNA sequence itself.
97
What does it mean for two genes to be linked?
They do not assort independently.
Occurs when two genes are very very close to each other not he same chromosome. Linked genes have a higher probability of being inherited together.
--> crossing over limits linked gene possibilities.
98
what is gene pool?
the complete set of genes and alleles in a population.
99
What is definition of evolution?
any change in the allelic frequency within a given gene pool across generations
100
what's polymorphism?
random variations in genetic sequence among individuals. Polymorphism are random usually due to mutation and may or may not be increasingly represented.
101
What's a niche?
very specific status or role an organism plays in its ecosystem. It can also refer to a specific habitat occupied by one organism within its ecological community.
102
what's survival of the fittest
term meaning that the individual best suited to its environment will be most likely to survive and pass on its genetic information to future generations.
103
what's natural selection?
the process by which individuals with genetic traits that provide them with a fitness advantage produce more offspring, and therefore those advantageous traits become more prevalent in subsequent generations.
104
what is adaptive radiation?
rapid formation of a variety of species from one ancestral species.
105
what is an evolutionary bottleneck?
sudden decrease in number of individuals in a population
106
what is genetic drift?
change in allele frequency within a population due to random non genetic non selective factors.
107
What is carrying capacity?
max number of individuals an ecosystem or environment can't sustain.
108
what's convergent evolution?
two species arrive at a point where they have similar functional forms, but they have developed those similar forms via different evolutionary pathway.
109
What's divergent evolution?
process by which species develop different forms and thereby form new species.
110
What's adaptive radiation?
example of rapid divergent evolution
111
4) If a male with a sex-linked recessive disease marries a normal female:
A) all of his daughters will be carriers
B) all of his sons will be carriers
C) all of his sons will be affected
D) one-half of his sons will be affected and one-half will be unaffected
a
112
what are the 5 hardy weinberg's equilibrium assumptions?
1) large population
2) no mutation
3) no immigration/ emigration - isolated
4) random mating
5) no natural selection
113
what are the two hardy weinberg's formula?
p2 +2pq+q2 =1
| p+q=1
114
in HW: what is p/q? what is p^2 & q^2? what about 2pq?
p and q are percentage of allele present as a fraction of all alleles in population
```
p^2 = fraction of individuals with homozygous dominant
q^2= fraction of individuals with homozygous recessive.
```
2pq= fraction of individuals with heterozygous genotype.
115
Fungi have cell .... made of .... .
walls; chitin
116
what are chemotrophs?
oxidize organic or inorganic compounds to harvest energy
117
what are phototrophs?
capture their own energy directly from the sun via photosynthesis
118
what are autotrophs?
capable of fixing CO2 and can therefore use CO2 as their carbon source for synthesizing organic molecules.
119
what are heterotrophs?
cannot fix CO2 and therefore must ingest organic molecules such as carbohydrates as their carbon source.
120
what's the difference between mutualism and commensalism and parasitism?
Mutualism is a form of symbiosis where both participants benefit equally.
Commensalism is symbiosis in which one participant benefits and the other participant’s experience is neutral— neither beneficial nor harmful.
Parasitism is a symbiosis wherein one participant benefits at the expense of the other
121
what are characteristics of viruses?
- contain nucleic acid and proteins
- bacteriophages have capsid head, tail and tail fibers.
- retrovirus have RNA
- DNa is in head
122
what is the lytic cycle of a virus? lysogenic cycle?
period during which viral genes are being actively transcribed and new viruses are assembled. --> goes on until cell enter lysogenic cycle or burst host cell.
lysogenic cycle is dormant cycle viruses during which viral DNA is incorporated into host's genome but new viruses are not being assembled.
123
what does gram positive mean?
-Stain purple
-Very thick cell wall
- Form endospores
-Single cell membrane
124
what does gram negative mean?
- Stain pink
- Relatively thin cell wall
- Do NOT form endospores
- Contain two (2) cell membranes: one inside the cell wall and one outside the cell wall.
125
A strain of bacteria being actively cultured in the lab develops a viral infection from the bacteriophage L. Pylobarium. One hundred percent of the bacteria test positive for the infection. The infected colony is plated out into separate colonies and cultured. After forty-eight hours, twenty percent of the colonies contain at least some bacteria NOT infected with the virus, while the remaining colonies are one hundred percent infected. This observation is best explained by which of the following?
A) Environmental impacts during the transfer killed some L. Pylobarium.
B) The immune systems of some of the bacteria were able to successfully destroy L Pylobarium.
C) Some bacteria developed antibodies in response to L Pylobarium.
D) Some bacteria underwent mutations that made them resistant to L Pylobarium.
d
126
what are characteristics of prokaryotes?
- no nuclei
- no membrane bound organelles
- no histones
- no chromosomes
- circular DNA
127
what are characteristics of eukaryotes?
- true nucleus
- complex
- membrane bound organelles
- linear DNA with histones
- chromosomes
128
what are characteristics of eukaryotes?
- true nucleus
- complex
- membrane bound organelles
- linear DNA with histones
- chromosome structure
- 80S ribosome
129
when does genetic variations occur ?
Genetic variation ONLY occurs via meiosis and only occurs at two points: 1) crossing over creates random recombination between chromatids, and 2) homologue pairs assort randomly at the metaphase plate, causing each daughter cell to receive a random assortment of chromosomes, some from mom and some from dad.
--> that's prophase I to prophase II of meiosis
130
What is the difference between the metaphase of mitosis, meiosis I and meiosis II?
mitosis have one line of XX lined up
meiosis I has TWO X’s lined up next to each other at the metaphase plate
meiosis II : anaphase II of meiosis looks just like anaphase of mitosis.
131
what is not a function of ER?
1) detoxification of cellular chemicals
2) lipid production and metabolism
3) synthesis site of extracellular proteins
4) post translational modification of proteins
2
132
Which of the following is an accurate list of various components found in a DNA strand?
Phosphodiester linkages, nitrogenous bases, amines, hydrogen bonds.
133
How does gas chromatography separate molecules?
separates materials according to their boiling point and will usually produce a unique peak for each unique compound or molecule.
134
How does genome of bacteria codes for these unique structure?
different genes code for one major element of the cell wall plus an enzyme that links the major element with another biomolecule.
135
what is true of fungi (4)?
- have cell walls containing chitin
- are haploid during large portion of their life cycle
- diget food before absorbing git
- capable of both sexual and asexual reproduction
ALL four
- have cell walls containing chitin
- are haploid during large portion of their life cycle
- diget food before absorbing git
- capable of both sexual and asexual reproduction
