Answer: True because In biology, evolution is the change in the characteristics of a species over several generations and relies on the process of natural selection. The theory of evolution is based on the idea that all species? are related and gradually change over time.
Well I'm not exactly certain where the teacher is going with this, but an often used example is red blood cells (RBCs) aka: erythrocytes.
RBCs are suspended in blood plasma as they flood through vessels around and around the body, so the osmolarity (amount of small particles that affect osmosis) must remain relatively constant. This is termed "isotonic", meaning the same amount of osmosis-influencing particles that are there inside the RBCs' cytosol, within their plasma membranes.
If the plasma osmolarity get too high, called hypertonic (as with extra salt particles) then water inside the RBCs will have an osmotic force driving it out of the cells' membranes, to flow where there are more salt particles. This will lead to cell shrinkage (called "crenation").
Counter to that, if the plasma osmolarity gets too low, as due to low plasma salt with excessive water intake (for example from the condition "water intoxication"), then the plasma will be hypotonic with respect to the intracellular cytosol concentration. This can result in water rushing into the RBCs' membranes via osmosis, causing the cells to swell from discs into spheres (balls), or even rupture and burst (a phenomenon called "hemolysis").
HOPE THOSE EXAMPLES HELP!!
Answer:
C)Parental: 41% Dr, 41% dR; recombinant: 9% DR, 9% dr.
Explanation:
The notation Dr/dR for genotypes means that one homologous chromosome has the alleles Dr and the other homologous chromosome has the alleles dR.
The heterozygous plant Dr/dR will produce 4 types of gametes: two identical to the chromosmes the individual has in its somatic cells (called parental), and two gametes which will be a mix of the alleles in the homologous chromosomes (called recombinant).
- Dr: parental
- dR: parental
- DR: recombinant
- dr: recombinant
To calculate the frequency of each type of gamete, we must use the formula:
Distance (map units) / 100 = frequency of recombination.
18 mu / 100 = 0.18.
The total frequency of recombination between the genes D and R is 0.18, but every time crossing over happens, two recombinant gametes are generated. Therefore, each recombinant gamete will have a frequency of 0.18/2=0.09 = 9%.
The frequency of parental gametes will be:
1 - frequency of recombinant gametes
1 - 0.18 = 0.82
But there are 2 parental gametes, so each of them will have a frequency of 0.82/2=0.41 = 41%.
23. centromeres
25. mitosis
27. cancer
29. sister chromatid
31. tissues
