6. Select the correct pair from the following options :
Answer
Genome – The complete genetic material present in an organism
7. Suitably arrange the information under the given headings.
Evokes sensations.
Co-ordinates the repeated movements during walking and running.
Impulses from the different parts of the body are transmitted to and fro the brain.
Co-ordinates muscular activities and maintains equilibrium of the body.
Answer
8. Analyse the following illustration and answer the questions :
(a) What proof of evolution does the illustration give ?
(b) Does the study of homologous organs give similar proof ? How ?
Answer
a) Biochemistry and Physiology : Different species which exists in today's worlds have a common ancestor.
b) Yes. We can observe basic similarities in the structure of internal organs even in living beings of different species. The external structure of the organs varies because they are to do different functions. Homologous organs are defined as the organs of different animals that are having a similar structure but differ in their functions. These give clear evidence that there was a common ancestor for all these living beings. Comparative morphology gives us enough evidence to prove evolution.
9. Analyse the following statements related to certain diseases and give the reasons for each.
(a) In hepatitis, dark yellow color appears in white portion of the eyes and the nails.
(b) In diphtheria, an ash colored thick coating forms in the throat.
Answer
a) The flow of bile secreted by the liver is blocked. There will be an increase in the level of the bile pigment which is called bilirubin in blood. This gives a dark yellow color to the mucus membrane, nails and white portion of the eyes.
b) Diphtheria affects mucus membrane of the nose and the throat. Diphtheria is a serious bacterial infection that affects the mucous membranes of the throat and nose.The bacteria produce toxins which destroy the cells of the mucus membrane. The cells destroyed by the toxins produce an ash colored thick coating in the throat.
10. Observe the picture and answer the following questions ?
(a) Name the part indicated as (i).
(b) How does myelin sheath form ?
Answer
a) Axon
b) Myelin sheath in the nerves is formed of Schwann cells. Myelin sheath in the brain and the spinal cord is formed of specialized cells called oligodendrocytes. Myelin is an insulating layer, or sheath that forms around nerves, including those in the brain and spinal cord. It is made up of protein and fatty substances. Oligodendrocytes are a type of large glial cell found in the central nervous system.
Genome – The complete genetic material present in an organism
7. Suitably arrange the information under the given headings.
Evokes sensations.
Co-ordinates the repeated movements during walking and running.
Impulses from the different parts of the body are transmitted to and fro the brain.
Co-ordinates muscular activities and maintains equilibrium of the body.
Answer
Brain
|
Spinal cord
|
Evoke sensation
|
Coordinates the repeated movements during walking, running
|
Coordinates muscular activities and maintains equilibrium of the
body.
|
Impulses from different parts of the body are transmitted to and from
brain through the spinal cord.
|
8. Analyse the following illustration and answer the questions :
(b) Does the study of homologous organs give similar proof ? How ?
Answer
a) Biochemistry and Physiology : Different species which exists in today's worlds have a common ancestor.
b) Yes. We can observe basic similarities in the structure of internal organs even in living beings of different species. The external structure of the organs varies because they are to do different functions. Homologous organs are defined as the organs of different animals that are having a similar structure but differ in their functions. These give clear evidence that there was a common ancestor for all these living beings. Comparative morphology gives us enough evidence to prove evolution.
9. Analyse the following statements related to certain diseases and give the reasons for each.
(a) In hepatitis, dark yellow color appears in white portion of the eyes and the nails.
(b) In diphtheria, an ash colored thick coating forms in the throat.
Answer
a) The flow of bile secreted by the liver is blocked. There will be an increase in the level of the bile pigment which is called bilirubin in blood. This gives a dark yellow color to the mucus membrane, nails and white portion of the eyes.
b) Diphtheria affects mucus membrane of the nose and the throat. Diphtheria is a serious bacterial infection that affects the mucous membranes of the throat and nose.The bacteria produce toxins which destroy the cells of the mucus membrane. The cells destroyed by the toxins produce an ash colored thick coating in the throat.
10. Observe the picture and answer the following questions ?
(b) How does myelin sheath form ?
Answer
a) Axon
b) Myelin sheath in the nerves is formed of Schwann cells. Myelin sheath in the brain and the spinal cord is formed of specialized cells called oligodendrocytes. Myelin is an insulating layer, or sheath that forms around nerves, including those in the brain and spinal cord. It is made up of protein and fatty substances. Oligodendrocytes are a type of large glial cell found in the central nervous system.
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