Inheritance Flashcards
How chromosomes separate during anaphase 1
Pairs of sister chromatids remain together but homologous pairs are separated
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Eukaryotic body cells have diploid nucleus which contains 2 copies of each chromosome in homologous pairs
Karyotype:
Number and type of chromosomes in a nucleus
DNA of bacteria is naked it means….
Its not associated with proteins
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early in the meiosis, homologous chromosomes pair up and crossing over and condensation follow
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DNA replication occurs before meiosis so that all chromosomes consist of two sister chromatids
What are those 44 chromosomes other than sex chromosomes called?
Autosomes
In the case of studying the chromosomes and their unique banding patterns fill in the blanks.
“division is……. At the end of……. When chromosomes are……
Halted(stopped)
prophase
Condensed
Where do the chromosome prepared for study come from?
May be taken from amniotic fluid in the case of fetus
Or from blood samples
What does a karyogram show?and what information can be obtained from it
A karyogram shows the karyotype of the cell( the number and type of chromosome)
It indicates the sex of an individual bc it shows the sex chromosomes
In prenatal diagnosis it is possible to check for chromosome abnormalities ( such as those leading to Down syndrome)
State the reason for this statement
“An organism’s complexity is not proportional to its genome size. Nor is variation in genome size proportional to the number of genes “
This is due to the high proportion of Non-coding dna that is found in some organisms
In what stages of meiosis does non-disjunction occur?
Anaphase ll
Can also occur at anaphase l
What is genome size?
Is the total number of nucleotide base pairs within one copy of a single genome
Compare the number of DNA molecules in eukaryotic and prokaryotic cells:
Prokaryotic cells:just one circular DNA
Eukaryotic cells: 2 or more chromosome types
What is karyogram?
A Karyogram show’s chromosomes in homologous pairs arranged in order of Decreasing length
Lac operon:
An operon found in some bacteria that controles the production of bata-galactosidase/permease and transacetylase
Difference between plants and humans letter style of genes?
Plant genes have been given a 2 letter abbreviation
Most Human»_space;3 letter
Regulatory gene:
A gene that codes for a protein that helps to control the expression of other genes
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Homozygous plants lele are genetically dwarf(کوتوله) as they don’t have the active form of gibberllin
What are the properties of a blood sickle cell?
Less soluble/when in low oxygen concentration it deformes the red blood cells to sickle cell shaped
How does active gibberllin make plant go tall?
Active gibberllin stimulates cell division and cell elongation in the stem
How can a plant grow tall?
Dominant allele for tallness Le
Recessive allele le> if both are le plant stays short forever
The dominant allele of this gene regulates the synthesis of the last enzyme in a pathway that produces an active form of gibberllin
Alleles:
A variety of a gene
Bivalent:
Each pair if homologous chromosomes
How much chiasmata exist in each pair of homologous chromosomes ?
Almost Always at least one and often several
Prophase of meiosis |
Chromosomes that already has been copied condense and become visible
Chromosomes arrange themselves in homologous pairs (each pair of homologous chromosomes is called bivalent)
Chromatid of one of these chromosomes intertwine with the chromatid of other(crossing point is called chisma)
Crossing over may occur
Centrioles migrate to opposite ends of cell and form spindle fibres made from microtubules. they attach themselves to centromeres of homologous pairs of chromosomes
The nuclear envelope breaks down
Nucleolus disappears
Metaphase of meiosis |
Spindle fibres attached to centromere
Move the bivalents to the equator of the cell
Homologous chromosomes in each bivalent remain attached at the chiasmata
Anaphase meiosis |
Spindle begin to pull the centromeres
Two whole chromosomes in each bivalent are pulled apart
Centromeres remain intact continuing to hold two chromatids of one chromosome firmly together
Telophase of meiosis |
Chromo Arrive at opposite ends of the dividing cell
Fibers break down
In most animal cells a nuclear envelope forms around each set and nucleolus generally reforms(not happen in plan cells)
Reduction division happens. the original cell was diploid with two sets of chromosomes. The new cell is haploid