Answer:
<em>Agrobacterium</em> <em>tumefaciens</em> is a gram negative bacteria that is responsible for tumor formation in the different parts of plant body.
Explanation:
It causes crown-gall disease in plant body by transferring it's DNA into the plant body which include Ti plasmid.
There are 3 types of bacteria that form tumor in different plant ares.
<em>Agrobacterium rhizogenes</em>,<em> Agrobacterium tumefaciens</em> strains contain either Ti or Ri plasmid but <em>Agrobacterium vitis</em> contain only Ti plasmid which are virulent.
The transfer of T-DNA takes place into the body of host cells and then the DNA is expressed into the body of the host and thus forming gall or tumor.
Answer:
The correct answer is -
1. right-handed
2. right-handed
3. positive
4. left-handed
5. negative
6. negative
Explanation:
In a circular bacterial chromosome, the structure of DNA is a right-handed double helix In a circular bacterial chromosome.
If DNA is twisted in the right-handed direction, it becomes overwound. Overwinding results in positive supercoiling takes place. If DNA is twisted in the left handd direction, it becomes underwound. Underwinding results in negative supercoiling.
f. One effect negative supercoiling in bacterial chromosomes is to promote separation of the two strands of DNA in the double helix
Adrenaline, Cortisol, Norepinephrine.
The pigments have a similar
structure of 40 carbon atoms covalently bonded in a chain. Carotenoids contain oxygen atoms in their chemical structure (retinyl functional group) while
xanthophyll does not. This makes carotenoids more non-polar compared to xanthophylls,
hence move farthest in chromatography
paper using a nonpolar mobile phase. Chlorophyll
pigment, on the other hand, has chlorin rings (which are larger) as functional
units hence move slowly in chromatography.
Photosynthetic rates
can be measured by either the amount of
oxygen they consume per particular time period
or the amount of carbon dioxide produced per particular time period. This
is conducted while immersed in water so
as to measure bubble rate formation in case of oxygen production or the change
in water pH in the case of carbon dioxide consumption.
When autumn approaches, the amount
sunlight received by the plant is reduced due to longer night than days. Deciduous trees have adapted by losing
chlorophyll a and b pigments (most important in photosynthesis)
during this time. This leaves a higher amount of the other red and yellow pigments hence making the leaves change from
green to yellow-red.
It is believed that this
is the result of an ancient endosymbiotic
relationship between a protist and a
eukaryotic cell. The protist generates energy
that the eukaryotic can utilize in its growth and reproduction while
the protist is sheltered. This relationship became obligatory symbiosis over
time.
Answer:
Venus is not ideal for supporting life because it has a thick atmosphere which causes extremely high temperatures.
Explanation:
- Venus is the second planet near to the sun in solar system.
- It is called the twin of Earth because of its almot similar size.
- It completes one revolution in 225 days.
- It is the hottest planet on in the solar system having temperature near 735 K which is more than mercury, the nearest planet to the sun.
- The high temperatures of Venus results from its extremely dense and Carbon dioxide rich atmosphere. The atmosphere is surrounded by thick clouds of sulphuric acid that cause sulphuric acid rains.
- It is known as evening star.
