Lesson: Life Processes
Kidneys in human beings are a part of a
system meant for ____________.
(a) nutrition
(b) respiration
(c) excretion
(d) transportation
(c)
The xylem in plants is responsible for
(a) transport of water
(b) transport of food
(c) transport of amino acids
(d) transport of oxygen
(a)
The autotrophic mode of nutrition
requires
(a) carbon dioxide and water.
(b) chlorophyll.
(c) sunlight.
(d) all of the above.
(d)
The breakdown of pyruvate to give
carbon dioxide, water and energy takes place in:
(a) cytoplasm.
(b) mitochondria.
(c) chloroplast.
(d) nucleus.
(b)
How are fats digested in our bodies?
Where does this process take place?
Fats are present in
the small intestine in the form of large globules. The small intestine receives
the bile salts from the liver. The bile salt breaks down the large fat globules
into smaller globules so that the pancreatic enzyme lipase can easily act on
them.
What is the role of saliva in the
digestion of food?
Saliva
contains a digestive enzyme called salivary amylase, which breaks down the
complex molecules (starch) into sugar.
What are the necessary conditions for
autotrophic nutrition and what are its by-products?
Conditions for autotrophic nutrition: Presence
of carbon dioxide, water, chlorophyll, and sunlight. By-products of autotrophic
nutrition: Carbohydrates and Oxygen
Aerobic respiration |
Anaerobic respiration |
It occurs in the presence of . |
It occurs in the absence of . |
It involves exchange of gases between an organism and outside
environment. |
Exchange of gases is absent. |
It occurs in cytoplasm and mitochondria. |
It occurs only in cytoplasm. |
It always releases and . |
End product is either lactic acid or alcohol. |
Yeast and bacteria use anaerobic mode
of respiration.
How are the alveoli designed to maximize
the exchanges of gases?
There are millions of alveoli in our lungs. The
presence of alveoli provides large surface for exchange of gases. The walls of
alveoli have an extensive network of blood vessels that ensure maximum exchange
of gases.
What would be the consequences of a
deficiency of haemoglobin in our bodies?
Haemoglobin carries oxygen in our blood.
Therefore, deficiency of haemoglobin in blood can affect oxygen supplying
capacity of the blood. This can lead to deficiency of oxygen in body cells and
lead to a disease called anaemia.
Describe double circulation in human
beings. Why is it necessary?
Humans are warm blooded. Therefore,
they need extra energy to maintain body temperature. To ensure this, it is
essential to maintain separation of oxygenated and de-oxygenated blood. To do that, blood flows in and out of the
heart twice. This is known as double
circulation.
What are the differences between the transport
of materials in xylem and phloem?
Xylem |
Phloem |
Xylem helps in the
transport of water and minerals. |
Phloem helps in the
transport of food. |
Water is transported
upwards from roots to all other plant parts. |
Food is transported in
both upward and downward directions. |
Transport in xylem occurs
with the help of simple physical forces such as transpiration pull. |
Transport of food in
phloem requires energy in the form of ATP. |
Compare the functioning of alveoli in
the lungs and nephrons in the kidneys with respect to their structure and
functioning.
Alveoli |
Nephrons |
Alveoli are sac like structures. |
Nephrons are tubular structures present inside kidneys. |
The walls of alveoli are one cell thick and they contain an extensive
network of blood capillaries. |
Nephrons are made of glomerulus, bowman’s capsule, and a long renal
tube. |
Alveoli are the site of gaseous exchange. |
Nephrons are a basic filtration unit. |
The exchange of and takes place between the blood capillaries
that surround the alveoli and the gases present in the alveoli. |
Blood enters the kidneys through the renal artery. The blood gets
filtered in nephrons. The nitrogenous waste in the form of urine is collected
by the collecting duct. |