Lecture notes Dr Scott Summer session Flashcards
Lecture notes from Dr. Scotts Summer session biology 1020 class
While in interphase how does DNA exist?
As chromatin
1 chromosome equals how many DNA?
1 piece of DNA just physically attached
After replication but before division a chromosome has what kind of chromatids?
2 sister chromatid (when they separate they are chromosomes)
cell division in prokaryotes is called
binary fission (two daughter cells identical to mother)
cell division in eukaryotes is called
Mitosis (two daughter cells identical to mother)
Does meiosis occur in prokaryotes?
No! Only eukaroyote (but not all)
90-95% of the cell life is spent where?
In interphase- the cell is working and doing it’s job
3 main parts of interphase
G1 phase
S phase
G2 phase
the cell is doing more than it is regular duties, growing and working which phase of interphase is this?
G1 phase
The cell starts to copy DNA, going from single stranded chomatin to the double stranded form. Which phase of interphase is this?
S phase
The cell is getting ready for division, making sure all organelles expanded enough. After this phase the cell will be ready to divide and enter Mitosis.
G2 phase
DNA is condensed into chromosomes. The centrosomes move and devide by pushing eachother with microtubes to the opposite poles of the cell. Creating fingers that reach out across the creating a spindle
Which phase in mitosis
Prophase
Which phase in mitosis- the nucleur envelope needs to be broke down, the spindles attach to the chromosomes at the centermere and have a pushing battle
Prometaphase
which phase of mitosis pushes the chromosomes to the middle of the cells equater. the cells line up
metaphase
the centermeres split the sister chromatids going from one double stranded chromosome to 2 single stranded chromosomes. The spindle fibers shorten and pull the chromatides apart creating a “V” shaped. Each pole has one copy of genome
Anaphase
Final stage of mitosis where there are two nuclear envelopes reforming creating to nuclei. Chromosomes disperse and spindles go away
Telophase
The division of the cytoplasm to make two cells
Cytokinesis
Membranes pulling in and creating two daughter cells
Cleavage furros
How do plants separate cells?
work from the inside and build a cell wall until it gets bigger and separates into two daughter cells.
the three check points (stops) to control cell cycle are located at
G1, M, and G2
G1 check point (stop) is located? and what is required to continue to the next level
at the end of the G1 point to enter s phase.
must have enough nutrients and be large enough and DNA must be good.
Where do cells go if they are stopped at the G1 Check and do not qualify to continue?
G0-for cells to never divide like nureons and skin cells
G2 check point
makes sure replication was successful and complete. Finds big errors
Metaphase check point
cell will not progess until all the chromosomes have lined up with two spindles attached to them.
Cell elongates and pinches off in the center creating two identical daughter cells is cell division in bacteria… which is..
Binary Fission
Why do cells divide?
For reproduction, growth and to repair
what are the pros to asexual reproduction?
fast, energy saving, passing 100% of your genes to your offspring
What are the cons to asexual reproduction
no genetic diversity the population is all the same
Recombination is
the exchange of information between the chromosomes can create new variations on the genetic gene
multi cell stage adult (2n) with in gonads there will be a sex cell that undergoes meiosis to form gamets (haploids) eggs and sperms (1n) the union of an egg and sperm by fertilazation makes a zygote (2n). what life cycle is this? Animals, fungi or plants?
Animals (diplonic life cycle)
multicellular organisms that are haploid. positive and negative gamete are produced by mitosis. when fertilized the two haploid gametes fuse to form a diploid zygote. immediatly dividing by meiosis to produce haploid structures called spores
Fungi life cycle
what is the only way that a haploid cell can divide?
through mitosis
Through meiosis in fungi do they produce gametes or spores?
spores
Meiosis only occur in animal life cycle True or Falso
False it is important in all 3 life cycles
what is a major difference between mitosis and meiosis?
2 rounds of cells that follow DNA replication
1 mother cell making twoidentical daughter cells
mitosis
1 mother cell making two daughter cells then they make 4 daughter cells
meiosis
Meiosis only occurs in what kind of cells?
Diploid or haploid?
diploid
when can crossing over occur?
prophase 1
What is crossing over?
exchange between non sister chromatids
what are two things that happen in meiosis that does not occur in mitosis?
Homogulous chromosomes and crossing over
anaphase 2 what separates?
homologues separate NOT chromatides
Mitosis–>DNA replication before mitosis–>mitosis occurs in all cells of the boyd–>mitosis ploidy diploid no reduction in chromosome numbers–>number of cell division, once cell division RESULTING IN HOW MANY DAUGHTER CELLS?
2 identical daughter cells
Meiosis–>DNA replication before Meiosis 1 only–>mitosis only occurs in the sex cells –>starting with diploid sex cells resulting in HOW MANY DAUGHTER CELLS?
4 unique gamates
Mitosis occurs where? in plant and fungi?
Sporangium where spores are reproduced
independant assortment
how the tetrads land on the metapase 1 plate (random)
biggest source of variation is?
Crossing over (the exchange of genetic material between non sister chromatides.
random fertilization
1 in 18 million possibilities
3 genetic variation sources
independant assortment
crossing over
random fertilization
what phase does crossing over occur in?
Prophase 1
In prophase 1 the exchanging of DNA between non sister cromatids is called
Crossing over
2 homogolous=4 different gametes Humans is 2 to the exponent 23 (chromosomes of gametes) is what kind of genetic variation? independant crossing over random fertiliazation
Independant assortment
a genetic variation where every sperm is 1 in 8 mil and the egg it randomly fertilizes is 1 in 8 mil creating a 1 in 64 million chance is what?
Random fertilization
What phase of meiosis does abnromal seperation of chromatid sisters occur in?
Anaphas 1 or 2
What is the abnormal seperation of chromatid sisters called?
Non disjunction
abnormal cell with 3 chromosome is called
N+1 because it has an extra chromosome
abnormal cell with 1 chromosome is called
N-1 because it is missing a chromosome
3 copies of one chromosome (n+1) is also called
Trisomy
Trisomy 21 is
Down syndrome- increase with mothers age- non-disjunction with eggs
Organism characteristic
Trait (flower color, position etc)
Specific characteristic
Phenotype (purple and white flowers)
DNA that encode for a protein
Gene (enzyme that makes the purple pigment)
has been altered and changed encodes for a protein
Mutant gene (faulty enzyme that does not produce pigment)
alternative form of a gene (one member of a pair) that is located at a specific position on a specific chromosome.
Alleles
3/4 purple and 1/4 white (3:1 ratio) on a monohybride cross is what kind of ratio
Phenotypic ratio (dominant versus recessive)
1 allele from each parent 50%
1 is homozygote recessive 2 are heterzygote and 1 is homozygote dominant is what kind of ratio?
1:2:1
Genotypic or phenotypic?
Genotypic
what kind of cross is taking the unknown and crossing it with a homozygous recessive to find out its genotype?
Test Cross
In a test cross if all the offspring are of the dominate phenotype (purple) the unknown parent was____ but if there was a 50/50 split then the parent is_____
Homozygous, heterzygous
Genes on separate chromosomes do not assort dependently they assort_______
independently
9:3:3:1 ratio is a phenotypical ratio of what kind of cross?
Dihybrid cross
1:1 ratio
Test cross when the unknown is a heterzygote
Recessive allele is not completely hidden
Incomplete dominance
1:2:1 ratio
incomplete dominance
the sequence of steps in the Mphase of the cell cycle is_____
prophase, prometaphase, metaphase, anaphase, telophase and cytokinesis
proteins that involved in regulation of the cell cycle and show fluctiations in concentration during the cell cycle are called
cyclins
________ and multiple alleles are illustrated of the ABO blood group in humans
Co-dominance
TRUE OR FALSE in metaphase 2 of meiosis the cell is halpoid and the chromosomes are double stranded
TRUE
In a cell the process of assembling a specific protein using the sequence of bases in mRNA is known as_______.
Translation
In eukaryotic cells DNA replication occurs_____>
during the S phase of the cell cycle
what are directly involved in translation?
mRNA
tRNA
large ribosome subunit
small ribosome subunit
in a cell the actual assembly of the correct number of amino acids in the correct sequence in a polypeptide chain is referred to as___
translation
