Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
141 Cards in this Set
- Front
- Back
|
Mitosis 3 purposes: These occur only in: |
development of an org from a zygote to embryo to fetus growth of an org repair damaged tissues somatic cells |
|
|
Somatic cells are defined as: They are_________, meaning they have ___ sets of chromosomes, one from each parent |
non-gamete producing cells diploid, 2 sets of chromosomes |
|
|
Somatic cells undergo ________, while _____ cells undergo meiosis Somatic cells produce identical ______ cells, while the other produces ________, or non-identical______. |
mitosis, while GERM cells undergo meiosis identical daughter cells, gametes or non-identical daughter cells |
|
|
Mitosis can be written as 2N>>2N Whereas Meiosis can be written as 2N>>1N |
see other side |
|
|
Mitosis is split into which 2 broad phases? What are the three parts of the first broad phase? The second is divided into which two phases? |
interphase and mitotic phase G1, S, G2 Mitosis and Cytokinesis |
|
|
_____ is the phase where a cell spends 90% of its life. The changes start when__________. After this, the ______ phase is initiated. Later, organelles and DNA are copied and the cell increases in size. |
Interphase, a cell receives a signal to divide. G1 is then initiated. |
|
|
_____ is the first phase when the cell checks itself and conditions to see if it can replicate. 5 things must be present to move to the next stage: If they are, the cell begins ____ phase |
G1 DNA is not damaged, sufficient nutrients, sufficient growth factor present, organelles duplicated, cell size adequate S (synthesis |
|
|
During G2 phase, ________ and another ________, ensuring that 2: |
the cell continues to grow and another check is performed, ensuring that duplication is finished and DNA is not damaged |
|
|
Phases of mitosis: |
PPMAT: Prophase, prometaphase, metaphase, anaphase, telophase |
|
|
In prophase, 3 things happen: |
chromatin condenses in chromosomes, centrosome pair begins to move to opposite sides of the cell, nucleolus and nuclear membrane breaks down |
|
|
In prometaphase, 2 things happen: |
nuclear membrane completely disintegrates, centrioles have arrived at poles and attached their microtubules to chromosomes via kinetochore |
|
|
the kinetochore... |
acts as a hook for microtubules to latch onto and is located in the centromere |
|
|
a _______ connects the centromere/spindle to the kinetochore, while a ________ does not connect but radiates off the spindle |
polar microtubule astral microtubule |
|
|
In anaphase of mitosis, _________ are pulled away from each other While this is happening the cell grows _____ and the poles move apart while the microtubules ______ |
sister chromatids longer, shorten |
|
|
In telophase, 4 things happen: |
nuclear envelope reforms chromosomes de-condense spindle apparatus (centrioles, microtubules, kinetochore) break down and disappear cytokinesis begins |
|
|
A trademark of cytokinesis or late telophase is the formation of ______ in animals or ________ in plants |
cleavage furrow in animals or cell plate in plants |
|
|
What are the two checkpoints and which is the most important? What is the G0 phase? |
G1, G2, G1 is the most important Cells that received the signal to divide, but did not receive the okay to continue to S phase. It can also be said that cells that are not in any of the other phases are in an indefinite G0 phase |
|
|
______ give the go-ahead signal for cells at G1 and G2, these are activated by _______. Build up of these two form complexes called _______, which acts to initiate mitosis. |
cdks, cyclin, mitosis promoting factor |
|
|
______ blocks cell cycle if DNA is damaged. If this mutated, you are at higher risk for ________. p21, p27, p57 bind to cyclin and cdk to prevent entry into S phase |
p53, cancer |
|
|
A third check is that ___phase will be delayed or terminated if microtubules are not attached to kinetochores |
anaphase |
|
|
An example of external signals is released by platelets, called ____________ (---), it promotes _______. |
platelet-derived growth factors (PDGF) angiogenesis - the development of new blood vessels |
|
|
Another example of external signaling is __________, when cells stop dividing because there are too many of them. 2 types: ___ cells do not exhibit this kind of dependence |
density-dependent inhibition contact inhibition - cells grown in culture rapidly divide until a single layer covers a petri dish anchorage dependence - cells must be attached to substratum, i.e. ECM in order to divide cancer |
|
|
Cancer cells form ________, if these remain at the original site, they are called ______, but if they can invade surrounding tissues, they are called ______ and may ________, exporting cancer cells to other parts of the body |
tumors, benign, maliginant, metastasize |
|
|
Chemotheraputic drugs target _____ dividing cells, but also affect normal ones like (3). In general, they attach an alkyl group to guanine in DNA, mutating DNA --> This prevents the ____ stage of interphase by substituting ____ for _____ |
rapidly, WBC, RBC, hair follicle S stage purines for pyrimidines |
|
|
_____ drugs prevent microtubule formation and are highly effective against childhood ____ ____ drugs prevent microtubules from separating. These are for 3: Topoisomerase inhibitors prevent ______. |
Vinca drugs, childhood leukemia Taxanes/ Taxol, lung, breast, ovarian prevent DNA replication |
|
|
Does asexual reproduction involve meiosis? What kind of org uses asexual reproduction? |
NO, only mitosis unicellular |
|
|
How do bacteria procreate? What is their cytokinesis called? |
Fission, budding |
|
|
In budding, which cell is intially smaller? |
the daughter cell |
|
|
Plants and some lower animals use another strategy other than mitosis, called ________, where small pieces break off and regenerate into a whole new organism |
fragmentation |
|
|
______ is reproduction that does not involve sperm or male gametes. An example of this ________, where an unfertilized egg develops into the whole new organism. |
agamogenesis parthogenesis |
|
|
In meiosis I, ______ are separated into two cells. In meiosis II, _______ are separated into two cells. What phases, respectively do these take place? |
homologous chromosomes sister chromatids anaphase I and anaphase II |
|
|
Meiosis I results in 2 ______ daughter cells Meiosis II results in 4 ______ daughter cells |
HAPLOID HAPLOID |
|
|
In Prophase I of Meiosis, 5 things happen, 2 of which do not happen in Mitosis: |
chromosomes begin to condense, nuclear membrane disintegrates, centrosomes move to opposite sides, homolgous chromosomes pair up and form a synapsis, crossing over occurs |
|
|
When homologous chromosomes pair up, it is called ______ and they form a _______. This leads to _____. This happens during _____ |
synapsis, tetrad, crossing over prophase I |
|
|
In Metaphase I of meiosis, 3 things happen: |
chromosomes line up in the middle of the cell, centrioles are at opposite ends, spindle fibers/ microtubules attach to homologous chromosomes as kinetochores |
|
|
In Anaphase I of meiosis, _______ are separated, but _____ remain attached In telophase I, chromosomes _____. This is usually followed by _______ |
homologous chromosomes are separated, but sister chromatids remain attached chromosomes arrive at opposite poles, usually followed by cytoplasmic division |
|
|
Does any chromosome replication occur between the end of meiosis I and start of meiosis II In Anaphase II, _______ separates In telophase II, a _________ forms around each set of chromosomes |
NO sister chromatids nuclear envelope |
|
|
Nondisjunction occurs during ________ of meiosis. __________ is when a diploid cell has an extra copy of a chromosome while _______ is when a diploid cell is missing one chromosome. |
anaphase I. trisomy, monosomy |
|
|
Not all species have a sexual cycle like humans, for example _____ and _____ are haploid for most of their lives. This is called ________. Humans and other animals have _______. Primitive plants like ____ and _____ alternate and have ________. |
protists and fungi have a haploid dominant lifecycle diploid dominant life cycle moss and ferns have an alternating haploid to diploid life cycle. |
|
|
3 mechanisms contribute to genetic variation: |
independent assortment of chromosomes, crossing over, random fertilization |
|
|
_______ means the sorting of maternal and paternal cells into daughter cells is random. The number of combinations of this is 2^23 in humans, or more than 8 million possible combos |
independent assortment of chromosomes |
|
|
_____ combines genes from two parents into a single chromosome. This is responsible for _____. |
Crossing over. Unusual traits like dark hair and light eyes. |
|
|
________ describes how any sperm can fuse with any ovum the fusion of gametes produces a zygote with any of about 64 trillion diploid combos |
random fertilization |
|
|
Pairs 1-22 are called ________ and pair 23 is called ________ |
autosomes sex chromosones |
|
|
genes are located on chromosomes in specific locations called _____ each chromosome has hundreds to thousands of genes genes on the same chromosome that tend to be inherited together are called ______ |
locus linked genes (ex: hemophilia and color blindness are both linked to x-chrom) |
|
|
3 ways non-humans determine sex: a gene located on either sex chromosome is called ____ |
temperature, social dominance, haploid/diploid (fertilized or unfertilized) a sex-linked gene |
|
|
The sex-determining region is called the ___ gene If it is present, _____ forms. If it is absent, ___ forms. |
SRY testes, ovaries |
|
|
3 sex-linked disorders: The ______ provides information concerning a gene's location: 3 7q3 |
color blindness, duchenne muscular dystrophy, hemophilia genetic map: which chromosome, long arm (q) or short arm (p), distance the gene is away from centromere 7th chromosome, long arm of chrom, 3rd genetic region from centromere |
|
|
In females, only one X is active. The other is called ______. However, if a female is heterozygous for a gene on the x-chromosome, she will be a mosaic for that character (caliclo cats - orange and black fur) |
a Barr body |
|
|
______ describes cells that have one more or one less chromosome due to non-disjunction of _______ during the _______ of ______. _______ is a condition in which an org has two or more complete sets of chromosomes. This is found in plants and gives rise to new species. |
aneuploidy, homologous chromosomes, anaphase I of meiosis polyploidy |
|
|
To induce polyploidy in plants, _____ is applied to the ______ of a branch. The cells are then ____. |
colchicine, terminal bud, 4n. |
|
|
Down syndrome is also known as ______. Problems include: 3 |
trisomy 21 mental retardations, muscle hypotonia (low muscle tone), macrogloassia (enlarged tongue) |
|
|
Trisomy 13 is also known as ______. Age of mother is a factor. Problems include: 4 |
Patau syndrome, mental retardation, microephaly (small head), polydactyl (more fingers or toes), low survival rate |
|
|
Trisomy 18 is also known as ______. Age of mother is a factor. Problems include: 4 |
Edward syndrome, heart, kidney and other organ abnormalities, very low survival rate |
|
|
XXY is called _______. Characteristics: 3 |
Klinefelter, tall, sterile , feminized |
|
|
XYY is called _________. 2: but otherwise they are phenotypically normal. They were once thought to be predisposed to criminal behavior |
jacob's syndrome, taller than average, may have slight mental impairment |
|
|
XXX is called _______. Only one X is active. Most females_______. Sometimes there may be: delayed development, weak muscle tone (hypotonia), curved pink fingers (clinodactyly), behavior and mental health problems, premature ovarian failure or ovary absnormalities, abnormal mestrual cycle. |
triple x syndrome. most females are phenotypically normal |
|
|
_________ is a female with only one X. 98% are spontaneously aborted. It is the only known ______ in humans. Characteristics: 4 |
Turner syndrome. Monosomy. Short, infertile, no functional ovaries, secondary sexual traits reduced |
|
|
4 types of changes in chromosome structure: ______ is when a segment of one chromosome joins to another non-homologous chromosome |
deletion, duplication, inversion, translocation translocation |
|
|
Most _____, when there is a loss of some segment of a chromosome, are lethal. An example of this is ______, the deletion of chromosome ______. Children with this are mentally retarded and have a cat-like cry. They usually die in early infancy or childhood. |
deletion, cri-du-chat, chromosome 5 |
|
|
Most________ have little to no affect on a zygote ____ are normally not harmful either as long as they are in balance - no extra or deleted genes and commonly occur on chromosome 9. |
duplications inversions |
|
|
Most cases of _______ are reciprocal. The most common is between ___ and ___. If chromosome __ and ____ swap, it is called _________. This gives a higher rate for certain cancers like CML (kind of leukemia), as well as infertility and mental retardation. |
translocations, 13 and 14, 9 and 22, philadelphia chromosomes |
|
|
______ are genes found in mitochondria and chloroplasts. These are inherited from ______. Scientists wishing to study evolution of maternal DNA look for changes over time in these genes. Some diseases affecting muscular and nervous systems are cause by defects in mitochondrial genes that prevent these cells ____. |
extranuclear genes, the mother, making enough ATP |
|
|
character variations are called ______. Mendel chose to track only those traits that were either/ or. He used varieties that were _______, meaning that the plants will produce offspring with the same traits as their parents. |
traits, true-breeding |
|
|
Mating two contrasting, ____ varieties is called ______. The parents are called the _____ generation, while the offspring are _____. When these SELF-POLLINATE, the ____ generation is produced |
true-breeding, hybridization P, F1, F2 |
|
|
Mendel's heritable factor = What is a definition of this? an alternative version of gene is called an _____. These account for variations in inherited characters. |
a gene a segment of DNA that specifies the synthesis of a particular protein allele |
|
|
For each trait, an organism inherits ____ alleles. These may be identical or they may differ. One of these will determine an org's affect on appearance, the other will have no noticeable affect |
2 |
|
|
________ aka _________ states that two alleles separate during gamete formation and end up in different gametes. Thus, an egg or sperm only gets one of the two present in the parent cell of an org. |
Law of segregation/ Law of independent assortment |
|
|
homozygous/ heterozygous - you know these genotype vs. phenotype does phenotype only include the outside? |
the alleles an organism possesses for a particular trait while phenotype is the physical expression of those alleles NO! It includes internal anatomy, physiology and behavior. It is ANY physical expression, not just an outer one. It also includes environmental history. |
|
|
A __________ is a good way to tell whether an individual's genotype is heterozygous or homozygous. It involves breeding it with a _______ individual. If the offspring is half and half, then we know it is homozygous. |
testcross homozygous |
|
|
A Punnett square with one trait is called a ______ cross, with two traits, it's called a _____ cross. |
monohybrid, dihybrid |
|
|
Mendel's law of _______ and law of ________ are the same thing, that.. This law only applies to which chromosomes? |
segregation and law of independent assortment, alleles segregate independently during gamete formation. The inheritance of gene is not dependent on the inheritance of another trait. non-homologous chromosomes |
|
|
There are 4 exceptions to Mendel's rules: |
alleles are co-dominant, incomplete dominant, when a gene/ trait has more than two alleles responsible for it, when one gene produces multiple phenotypes/ characteristics |
|
|
In ______, both alleles are expressed. An example of this is: In ________, one allele is expressed and the other is expressed as a "lack", making the phenotype fall in between the spectrum. An example of this is: |
co-dominance, blood types incomplete dominance, pink flowers |
|
|
T of F, most genes have more than two alleles? ______ describes a single gene that can have multiple phenotypic effects. 3 examples of this: |
T pleiotropy: PKU (mental retardation, reduced hair an skin pigmentation), Cystic fibrosis (respiratory, digestive, greasy stool, club fingers and toes), sickle-cell disease (anemia, pain, jaundice) |
|
|
T of F dominant alleles are always the most common? 2 Examples |
F polydactyl (multiple fingers and toes) and Huntington's are both dominant but relatively rare |
|
|
______ describes when two or more genes interact to control a single phenotype. Genes can mask each other's presence or combine to produce an entirely new trait. Ex: mice have a gene for hair color and a gene for whether that color is deposited in the hair or not. |
epistasis |
|
|
Another example of epistasis is peppers, which has a gene for red and yellow, but also a gene for absence of chlorophyll (making it red or yellow) or presence (masking the yellow and making it orange or green). Additional examples: Black and Yellow may make brown babies, chicken beaks, baldness |
epistasis means one species, many phenotypes. Butterflies are an example of this |
|
|
_________ describes traits that vary in the population along a continuum. They are determined by a group of genes called ________ |
quantitative phenotypic trait, polygenic |
|
|
_______ also has an impact on phenotype. For example, hydrangea flowers vary in color depending on the pH of the soil. Other alleles, such as those for arctic foxes are related to ______. Explain: |
the environment temperature - pigments are only produced when it is warm, siamese cats - pigments are only produced when weather is cold |
|
|
traits such as skin, height and hair could be called _______, or ______ |
quantitative phenotypic traits or multifactorial |
|
|
__________ is a record of interrelationships of parents and children across generations. These can trace inheritance patterns, as well as make predictions about future offspring. You can only a carrier if the disease is recessive. |
pedigree |
|
|
Autosomal recessive diseases: PKU, cystic fiibrosis, tay-sacks, sickle-cell anemia, thalassemia (mediterranean anemia), galactosemia (lactose intolerance), albinism |
see other side |
|
|
PKU is when an individual cannot convert the _________ to ______ due to lack of _______ hydroxylase. It is instead converted to _________. Build up of this is toxic and leads to _______ and ____, as well as various other symptoms. It can be treated with a diet low in phenlyalanine. |
amino acid phenylalanine, tyrosine, phenlalanine hydroxylase mental retardation ADHD |
|
|
_______ is the most common genetic disease in the U.S. It results in _________, leading to various physiological effects. |
cystic fibrosis, defective or absent chloride channels in the plasma membranes |
|
|
Effects of cystic fibrosis: 4 |
mucus build up in lungs leading to pneumonia, damage to insulin producing pancreatic cells leading to diabetes, blocks transport of digestive enzymes into small intestine (can't digest and absorb food), sterility in men and some women |
|
|
In Tay-Sach disease, individuals are missing an enzyme called ____, used to break down _____ called _______. The build up of these in ______ causes cell death. This results in deterioration in mental and physical abilities and death by age 4. Ashkenazi jews and cajuns of louisiana. |
Hex A, fatty acids called gangliocides, neurons |
|
|
Sickle Cell disease is caused by the _______ of a single amino acid in _____________, causing it to have a sickle cell shape. Symptoms include physical weakness, pain, organ damage, poor immunity and ability to heal, ulcers, paralysis, death. May have evolved to fight malaria - seems to help carriers |
substitution, hemoglobin protein RBC |
|
|
Thalassemia is caused by a faulty RECESSIVE gene that causes ____________, leading to severe 4 |
abnormal hemoglobin production, severe anemia, hemochromatosis (high Fe), bone abnormalities, spleen enlargement |
|
|
mating of close relatives is also called ___________. The consequences of which are determined by the founder's effect. |
consanguineous |
|
|
4 dominant disorders: |
huntington disease, achondroplasia, neurofibromatosis, progeria |
|
|
Huntington's Disease is due to ______. It causes gradual brain damage, causing involuntary movements, nervous system deterioration and dementia leading to heart complications and death. Symptoms don't show up in a person until 30's-40's. |
repeats of CAG nucleotides on chromosomes, over 40 repeats become affected. |
|
|
Achondroplasia, homozygous dominant leads to _______ while heterozygous leads to ______. |
still birth or death just after birth a type of dwarfism, short arms and legs relative to other body parts |
|
|
Neurofibromatosis (Reckinghausen disease) is caused by __________, which cause painful bumps under the skin, colored spots, skeletal problems and other neurological problems. |
nerve tissues growing tumors |
|
|
Hutchinson-Gilford Progeria is ______ mutation which causes an abnormal protein called _______ to be made. This _________ and causes death in early teens. |
a spontaneous mutation, progerin, inhibits mitosis and thus cell division, causing the person to age rapidly |
|
|
A ______ describes genes that are found only on X chromosomes. Only ______ are carriers. ______ describes people who lack proteins need for normal blood coagulation |
x-linked allele, females hemophilia |
|
|
In Duchene Muscular Dystrophy, individuals lack ______, a component of muscle. This leads to____ |
dystrophin protein, muscle degeneration, movement and breathing difficulty and eventually death |
|
|
4 tests to identify carriers of genetic diseases: |
Amniocentesis, chorionic villi sampling, fetoscopy, ultrasounds |
|
|
In amniocentesis, ______ is removed and ______ are isolated, grown, fixed, stained and a ____ is created. It can be done between __________. |
amniotic fluid is removed and fetal cells, karytope 14 and 16 weeks |
|
|
In chorionic villus sampling, the _______ part of the placenta removed and a ________ is created. This can be carried out at_______. It has a higher risk than amniocentesis, including miscarriage, fluid leaking to hypolastic lungs and digit-reduction defects. |
chorion, karyotype, 10-13 weeks |
|
|
A fetoscopy is performed by: It is done after _____ to defect birth defects like spina bifida and _______ |
inserting an endoscope into the amniotic sac to allow the doctor to see the fetus the 18th week, get a biopsy of umbilical cord |
|
|
_______ uses low sound frequency to visualize a fetus. It is performed to determine: 4 |
ultrasound gestation age, fetal viability, location of fetus, number of fetuses and sex of fetus |
|
|
_________ worked at Columbia University and determined that genes are located on chromosomes. He also discovered ______. He is considered the Darwin of genetics. However, he could not determine ______ |
Thomas Morgan. sex chromosomes which two components, DNA or protein, was responsible for heredity. |
|
|
_________'s work in 1928 suggested than DNA was the heredity factor and that cells were capable of _________. This means that ________. He worked with strep, a pathogenic strain ____ and a harmless strain, _____. When he mixed heat killed pathogenic with live harmless, some of the live became pathogenic. Antiobiotic resistance is party due to transformation. |
Frederick Griffith's, transformation, a change in genotype and phenotype due to the uptake of foreign DNA, S, R |
|
|
In 1944, ______, McCarty, and MacLeod determined that________ |
Avery, DNA was the transformation factor that turned live rough bacteria into dead smooth bacteria |
|
|
_________ are viruses that feed on bacteria. How were they used as evidence that DNA was the transformation factor? ______ is the specific name of the virus. |
bacteriophage, They inject their DNA into the bacteria but the protein shell remains outside, T2 phage |
|
|
________ provided more proof that DNA was the genetic material. They injected some T2 phages with_________ and some with _______. The sulfur was incorporated into the viral shell while the phosphorus went to the DNA. When the virus infected E. Coli, ________ was found inside the cell. |
Hershey and Chase, radioactive sulfur, radioactive phosphorus, radioactive phophorus |
|
|
By the 1950's it was already known that DNA is polymer of nucleotides, each consisting of nitrogenous base, a sugar and a phosphate group. The challenge was to determine how its structure accounts for its role. |
see other side |
|
|
___________ and ________ would help with that. They were using a technique called ________ to study molecular structure. _______ produced a picture of DNA using this technique. She helped _____ and _____ show that the structure of DNA is a double helix in 1953, although she received no credit for it. |
Wilkin and Franklin, x-ray crystallography, Franklin, Watson and Crick |
|
|
Watson and Crick had thought ________, but Franklin's picture showed ______. |
That bases like A and A pair together, purines must pair with pyrimidines for the width to be consistent with the x-ray. |
|
|
Purine: Pyrimidine: |
A and G T/U and C |
|
|
During DNA replication, the original parent strand unwinds and each strand of the double helix acts as a template for building a new strand. The new DNA is thus composed of one old strand and one new strand. This is called ___________. This important because _________. |
semiconservative. Each parent strand remains intact. |
|
|
A special site where DNA replication begins is_________. Here the enzyme, ________ untwists the DNA and breaks the hydrogen bonds between the bases on the DNA double strand, forming a bubble, called the ______. A eukaryotic chromosome can have hundreds to thousands of these sites. |
origin of replication, helicase, replication bubble |
|
|
At the end of each bubble is a _________, y-shaped regions where new DNA will form. The enzyme _______ adds nucleotides only to a free 3' end, this means the new strand can elongate only in the _______ direction |
replication forks, DNA polymerase, 5' to 3' direction |
|
|
Continuously produced strands are called _______, while some must be made and then stitched together. These are called _______ or _______. This caused by DNA polymerase's 5' to 3' end requirements |
leading strands, lagging strands or Okazaki fragments |
|
|
___________ is an enzyme that prevents "over-winding" ahead of the replication forks by breaking, swiveling and rejoining DNA strands. |
topoisomerase |
|
|
An enzyme called ______ synthesizes RNA primer at the 5' ends. DNA cannot be duplicated unless... Priming is done by adding short RNA nucleotide onto the DNA template strand. Only one primer is needed to syntheizse the leading strand, but ________ |
primase, it is primed, the lagging strand must be primed multiple timese |
|
|
_______ copies the leading strand and Okazaki fragments by adding complementary nucleotides to them. Each nucleotide added to a growing DNA strand is a ________. _________ removes primer from 5' ends, which is then replaced with DNA. |
DNA polymerase III. Nucleoside triphosphate. DNA pol I
|
|
|
_____ binds to and stabilizes the single-stranded DNA so they do not reform into double strands |
SSB - single-strand binding |
|
|
_______ joins newly formed DNA fragments of the lagging strand and joins the leading strand to the primer DNA. |
DNA ligase |
|
|
__________ proofread newly made DNA, replacing incorrect nucleotides by correcting errors in base pairing, cutting out and replacing damaged stretches of DNA |
DNA polymerases |
|
|
________ mark the end of a nucleotide sequence and shorten every time the chromosomes are duplicated. When these get too short, the cell can no longer divide and it undergoes _________, which is also known as _______. This is associated with aging, cancer, death. This is why telomeres have been compared with a bomb fuse. |
telomeres, apoptosis, cell suicide |
|
|
Telomeres have 3 additional purposes: |
protect genes near the ends of the chromosomes, prevent homologous chromosomes from re-arranging (inversion), prevent non-homologous chromosomes from fusing with each other |
|
|
If chromosomes did not have telomeres, what would happen? However, an enzyme called _______ catalyzes the lengthening of telomeres in 5: |
The replication process would shorten the genes and essential chromosomes would be missing fetal cells, germ cells, stem cells, cancer cells and some WBC |
|
|
______ is the process by which DNA directs protein synthesis. It includes two stages: |
gene expression transcription, translation |
|
|
Transcription is: It requires: This creates: 3: |
the synthesis of RNA using DNA as a template RNA polymerase enzyme Messenger RNA (m-RNA), Transfer RNA (t-RNA), Ribosomal RNA (r-RNA) |
|
|
Translation is: It's based on ______ found on ________. It takes place in the _______. |
the assembly of amino acids into a polypeptide the information from codons found on mRNA ribsosomes |
|
|
_______ becomes a component of the ribosome. |
ribosomal RNA. A ribosome is 40% protein and 60% RNA. |
|
|
_______ plays a role in translation by binding amino acids and bringing them to the ribosome. Each kind of t-RNA can bind to ________ |
Transfer RNA (t-RNA), only to one specific amino acid. |
|
|
_________ contains information (code) that directs how the 20 amino acids will be joined together. It also contains information: |
Messenger RNA, on when to start and when to stop translation |
|
|
In prokaryotes, mRNA can be immediately used, in eukaryotes it must be processed before use in translation. The genetic code (codon) on mRNA is nearly universal, shared by the simplest bacteria to the most complex animals. Genes can be transcribed and translated after being transplanted from one species to another. |
see other side |
|
|
The three stages of transcription: |
initiation, elongation, termination |
|
|
In initiation, _________ bind to regions on the DNA called _________. In prokaryotes, these sequences are _______ and _______. In eukaryotes, _____. |
Transcription factors, promoters TATA (10 box) and TTGACA (35 box) the promoter region varies and is very complex. |
|
|
Binding of transcription factors causes ________ to bind to the TF's/ DNA complex. The whole thing then becomes known as__________. |
RNA polymerase II, transcription initiation complex. |
|
|
RNA polymerase II: 2: |
unwinds DNA double strands and hooks together RNA nucleotides that are complimentary to the 3' and 5' DNA strand |
|
|
RNA sythnesis follows the same base pairing rules as DNA, except _______ substitutes for _______. The stretch of DNA transcribed is called a ____________ |
uracil, thamine transcription unit |
|
|
Prokaryotes have two termination mechanisms: _______ , where transcription stops when synthesized RNA forms a G-C hairpin loop followed by a series of U nucleotides, and ____ where rho protein causes detachment of mRNA and RNA polymerase from DNA |
Rho independent, Rho dependent |
|
|
RNA polymerase I codes for______ RNA polymerase II codes for____ RNA polymerase III codes for ________ |
genes the code for large RNA molecules found in ribosomes protein-coding genes (m-RNA) t-RNA and rRNA |
|
|
modification of pre-mRNA is called ________ It involves removal of _________ called _____ and rejoining of _____ called______ |
RNA processing non-coding sequences called introns and rejoining of coding sequences called exons |
|
|
RNA processing is performed by ________, RNA molecules that function as enzymes and can cut RNA, and __________, molecules made up of small nuclear ribonucleoproteins (______), a RNA/protein that has catalytic function |
ribozymes, spliceosomes, snRNP |
|
|
RNA processing also involves ______ and ______ |
addition of a 5' cap and poly-a-tail |
