a) The cell membrane is semi permeable- The pores that occur on the cell membrane allows the passage of the small size molecules but does not allow the passage of the large sized molecules.
Such a membrane is said to be selectively permeable or semi-permeable. In particular, when a cell is surrounded by a dilute sugar solution, the small sized water molecules will enter the cell but the larger sugar molecules will not pass through the cell membrane.
In contrast, the cell wall is permeable as it allows both sugar and water molecules to pass through it; it has larger pores. This property of selectively permeability enables the cell membrane to select what enters and leaves the cell.
b)The cell membrane is sensitive to changes in temperature and pH- Cell membranes are made up of protein. Proteins are adversely affected by extreme changes in temperature and pH.
Changes in temperature and pH will alter the structure of the cell membrane thereby hindering the normal functioning of the cell membrane. High temperature denatures (destroys) the proteins thereby impairing the functions of the cell membrane.
c)The cell membrane possesses electric charges- The cell membrane has both positive and negative charges. These charges affect the manner in which substances move in and out of the ells. The charges also enable the cell to detect changes in the environment.
simiyu kelly answered the question on September 15, 2017 at 11:34
-
a) What is magnification? (b)Give the formula used to calculate magnification in a light microscope
(Solved)
a. What is magnification?
b. Give the formula used to calculate magnification in a light microscope
Date posted:
September 15, 2017
.
Answers (1)
-
1. (a) what is classification? (b) List the external features used to classify plants (c) List the external features used to classify animals...
(Solved)
a. What is classification?
b. List the external features used to classify plants
c. List the external features used to classify animals
d. Give the reasons why classification is important
e. Name the taxonomic units of classification in descending order
Date posted:
September 15, 2017
.
Answers (1)
-
Describe how herbaceous plants obtain their support?
(Solved)
Describe how herbaceous plants obtain their support?
Date posted:
September 13, 2017
.
Answers (1)
-
State the economic importance of the following excretory products in plants (i)Nicotine (ii)Quinine
(Solved)
State the economic importance of the following excretory products in plants
i)Nicotine
ii)Quinine
Date posted:
September 13, 2017
.
Answers (1)
-
Name the causative agent of whooping cough
(Solved)
Name the causative agent of whooping cough
Date posted:
September 13, 2017
.
Answers (1)
-
The equation below represents a metabolic reaction that occurs in the mammalian liver
Amino acids -------> Organic compounds + urea
(Solved)
The equation below represents a metabolic reaction that occurs in the mammalian liver
Amino acids ------->Organic compounds + urea
(a) Name the process
(b) What is the course of amino acids in the process?
(c) What is the difference between essential and non-essential amino acids?
Date posted:
September 13, 2017
.
Answers (1)
-
Why do guard cells lie in close association with epidermal cells?
(Solved)
Why do guard cells lie in close association with epidermal cells?
Date posted:
September 13, 2017
.
Answers (1)
-
State two adaptations of tracheal system in insect to its functions
(Solved)
State two adaptations of tracheal system in insect to its functions
Date posted:
September 12, 2017
.
Answers (1)
-
Name the blood vessel that transports blood from small intestine to the liver
(Solved)
What is the name given to the blood vessel that transports blood from small intestine to the liver?
Date posted:
September 5, 2017
.
Answers (1)
-
The diagram below represents bones at a joint found in the hind limb of a mammal.
(Solved)
The diagram below represents bones at a joint found in the hind limb of a mammal.
(a) Name the bones labeled X, Y and Z
(b) (i) Name the substance found in the place labeled W.
(ii) State the function of the substance named in (b) (i) above.
(c) Name the structure that joins the bones together at the joint.
(d) State the differences between ball and socket joint and the one illustrated in the diagram above.
(e) Name the structure at the elbow that performs the same function as the same function as the patella.
Date posted:
May 26, 2017
.
Answers (1)
-
The diagram below represents a mammalian pelvic girdle.
(Solved)
The diagram below represents a mammalian pelvic girdle.
(a) State the function of obturator foramen.
(b)(i) Name the bone that articulates with the pelvic girdle at acetabulum.
(ii) Name the type of joint formed by the acetabulum and the bone named in (c) above
(c) Name a bone formed by the fusion of caudal vertebrae in human beings.
Date posted:
May 26, 2017
.
Answers (1)
-
The diagram below illustrates the arrangement of bones and muscles in the human arm.
(Solved)
The diagram below illustrates the arrangement of bones and muscles in the human arm.
(i) Name the bones labelled K and L.
(ii) Explain how the upwards movement of the lower arm is brought about by the bones and muscles shown in the diagram above.
Date posted:
May 26, 2017
.
Answers (1)
-
State the difference between ball and socket and hinge joint
(Solved)
State the difference between ball and socket and hinge joint
Date posted:
May 25, 2017
.
Answers (1)
-
Name three types of skeletons found in multicellular animals.
(Solved)
Name three types of skeletons found in multicellular animals.
Date posted:
May 25, 2017
.
Answers (1)
-
State three structural differences between biceps and muscles of the gut.
(Solved)
State three structural differences between biceps and muscles of the gut.
Date posted:
May 24, 2017
.
Answers (1)
-
State three ways in which support is brought about in a leaf.
(Solved)
State three ways in which support is brought about in a leaf.
Date posted:
May 24, 2017
.
Answers (1)
-
State three ways by which plants compensate for lack of ability to move from one place to another.
(Solved)
State three ways by which plants compensate for lack of ability to move from one place to another.
Date posted:
May 24, 2017
.
Answers (1)
-
What makes young herbaceous plant remain upright?
(Solved)
What makes young herbaceous plant remain upright?
Date posted:
May 24, 2017
.
Answers (1)
-
State the importance of tactic response among some members of kingdom protista.
(Solved)
State the importance of tactic response among some members of kingdom protista.
Date posted:
May 24, 2017
.
Answers (1)
-
The diagram below represents the transverse section of the spinal cord.
(Solved)
The diagram below represents the transverse section of the spinal cord.
(a) Name the part labelled H.
(b) State two functions of the fluid found in the parts labelled J.
(c) Give a reason for the colour of white matter.
Date posted:
May 24, 2017
.
Answers (1)