Answer:
no your 1st answer is wrong it must be a deer beacause it affects the food chain of many carnivores.
Explanation:
- d
- a because it will definitely affect the eco system
- c it's the correct answer
- c it's also the correct answer ☺️
Answer:
Watson and Crick proposed the double helical model of DNA.
Explanation:
- This model says that DNA exist as double helix. It has two polynucelotide strands running in opposite direction i.e the strands are anti-parallel.
- Each polynucleotide strand is made up of several nucleotide liknked together by phophodiester bonds.
- The two strands are not coiled upon each other but the double strand is coiled upon itself around a common axis like the spiral stair case. Here base pairs forms the stairs and backbone of two strands form railing. Back bone contains sugar and phosphate.
- The base pairing is specific, adenine always pairs with thymine and guanine always pairs with cytosine. Thus if we see any base pair, it consists of one purine and one pyrimidine.
- The two strands of DNA thus show complementary base pairing.
- The strands are held together because of hydrogen bonding between the bases in opposite strand.
- One full helical turn involves ten base pairs and the base pairs are stacked 3.4 A apart.
- This form is called as B-form of DNA.
Phospholipid bilayers are critical components of cell membranes. The lipid bilayer acts as a barrier to the passage of molecules and ions into and out of the cell. However, an important function of the cell membrane is to allow selective passage of certain substances into and out of cells.
<u>Answer:</u> The weight of the person above the surface of a planet is 635.83N.
<u>Explanation:</u>
To calculate the weight of a person, we use the formula:
....(1)
where,
w = weight of an object
m = mass of the person = 65kg
g = acceleration due to the gravity of the planet
For the calculation of weight, we need to first find the acceleration due to gravity and for that we use the formula:
where, g = acceleration due to gravity = 
G = Universal gravitational constant = 
M = mass of the planet = 
r = distance of the person from the planet = 
Putting values in above equation, we get:
Putting this value in equation 1, we get:
Hence, the weight of the person above the surface of a planet is 635.83N.
<h2>Transportation across the membrane</h2>
Explanation:
(a) Simple diffusion; Faciliated diffusion-Directions in which two transported solutes move
- In simple diffusion diffusion of non polar compounds across the membrane and along the concentration gradient without the involvement of protein whereas in case of facilitated diffusion membrane transport proteins that facilitate movement pf molecules across the membrane down its concentration gradient
- Both the diffusions does not require energy
(b) Facilitated diffusion; active transport-Direction the solute moves relative to its concentration gradient
- In facilitated diffusion membrane transport proteins that facilitate movement of molecules across the membrane down its concentration gradient without the expenditure of energy
- Active transport drives transportation of solute against the concentration gradient across the membrane
(c) Simple diffusion; Active transport-Directions in which two transported solutes move and Direction the solute moves relative to its concentration gradient
- In simple diffusion diffusion of non polar compouds across the membrane and along the concentration gradient without the involvement of protein and energy
- Active transport drives transportation of solute against the concentration gradient across the membrane;secondary active transporters coupled with transportation of two solute molecules
(d) Direct active transport; Indirect active transport-Direction the solute moves relative to its concentration gradient or its electrochemical potential
- Direct active transport use direct energy such as ATP hydrolysis,oxidation and sunlight energy
- Indirect active transport use indirect energy such as chemical gradient,electrochemical gradient established by direct active transporters;one solute moves along the concentration gradient while other moves against the concentration gradient
(e) Symport; Antiport-Direction in which two transported solutes move
- In symport both the solute molecules move in same direction;coupled with primary active transport(direct transport)
- In antiport both the solutes moves in opposite direction;coupled with secondary active transport(indirect transport)
(f) Uniport; coupled transport-Directions in which two transported solutes move
- Uniport is the transport of single solute across the membrane
- Coupled transport is the transport of two solute molecules across the membrane;it may be symport or antiport
(g) P-type ATPase; V-type ATPase-Kinetics of solute transport
- P-type ATPase always transport cations and undergoes phosphorylation
- V-type ATPase(here V stands for vacuole) transport protons and no phosphorylation occurs;catalytic activity is not reversible
- Both are types of primary active transporters
