Matric Notes Biology Class 9th Ch 1 Introduction to Biology Extra Short & Long Questions

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Short Questions

Q.1) How the understanding of physics can help the biologist?

Answer:  Biology is the study of living organisms and physics is the study of matter and the laws of nature to understand the behavior of matter and the universe. Biophysics is an interdisciplinary study of the understanding of biological phenomena and problems using the principles and techniques of physics. Biophysics is used in physiology, bioenergetics, neurosciences, pharmacology etc.

For example:

• Physics helps explain how bats use sound waves to navigate in the dark
• How wings give insects the ability to move through the air.
• Photosynthesis follows the laws of physics during absorption of light.

Q.2) Which career would you like to adopt after studying biology and why?

Answer: After studying biology, I would like to adopt animal science or animal husbandry. It is a branch of biology which deals with the breeding and raising of livestock (domestic animals). Professional courses in this field are taught in many universities. I can also work for veterinary hospitals, the pharmaceutical industry, the livestock department, and the pet food industry or research in livestock and dairy development to fulfil the food requirements.

Q.3) Write the translation of any three verses of the Holy Quran related to the creation of mankind.

Answer: Verses of Holy Quran related to mankind:

• Allah is Creator of all things, and He is Guardian over all things.
• He created man of clay like the potter’s
• Who made all things good which he created, and He began the creation of man from clay

Q.4) Name few Muslim scientists and their contributions in the field of biology and medicine.

Answer: Muslim scientists and their contributions

  Muslim scientists contributed a lot of knowledge to the science of biology and medicines from the 8th to 15th century. Their views were highly respected. Some of the famous Muslim scientists are:

1- Jabir Bin Hayyan (721 – 815 AD):

       He was born in Iran and practiced medicine in Iraq. He introduced experimental chemistry and also wrote a number of books on plants and animals. Among these “Al-Nabatat” and “Al-Hayawan” are noteworthy.

2- Abdul Malik Aasmai (740 – 828 AD):

         He was regarded as a specialist in animal sciences. He wrote many books on animals and plants. One of his books “Al-Kheil” is about horses, another, “Al-lbil” about camels, a third “A-sha” about sheep and fourth “Al-Wahoosh” is about wild animals. In the book “Khalaq-ul-Insan”, he had described different parts and functions of human body.

3- Bu Ali Sina (980 -1037 AD):

      He was among the greatest Muslims scientists and his most valuable contribution was in the field of medicines. He was an expert in Mathematics, Astronomy, Physics and Palaeontology. He worked on the structure, function and diseases of the eye. He described 130 diseases of the eye in his book. His book “Al-Qanun-fil-Tibb” was translated into many European languages.

4- Abu – Usman Umar Aljahiz:

        He wrote the famous book “Al- Haywan” which described his own observations on animals, such as the seasonal migration of fish in river Tigris. Similarly, he described the life system of an ant.

5- Al-Farabi:

       This renowned Hakim and biologist lived in 870 – 950 AD. He wrote two books “Kitab-ul-Nabatat” which is about plants and ” Kitab-ul- Haywanat” which is about animals.

Q.5) What level of organization is represented by volvox?

Answer: Colonial organization:

Volvox is a green alga. It is a common example of unicellular colonial organisms. It lives in water. Hundreds of volvox cells make a small volvox colony. Many small colonies make a big colony. Most of the functions are performed by every cell. However, an individual volvox cell cannot live independently as the cells of the colony are dependent on each other.

For example:

 There are cells which are specialized for mobility while other cells are for reproduction. Therefore, the division is above the cellular level and this is a trend towards the more complex division of labour in multi-cellular organisms.

Long Questions

Q.1) How the understanding of biology can be improved through the knowledge of geography, chemistry, and statistic? Give examples.

Answer: Linkage of Biology with other Fields of Study:

 The functions and metabolic pathways occurring in living organisms follow the principles of other fields of study like physics, chemistry, geography, economics etc. This type of linkage makes inter-disciplinary sciences. Some of the inter-disciplinary sciences are mentioned below:

1- Biogeography:

       Biogeography is the study of the distribution of organisms in space and time.

For example:

  In biogeography, we study why polar bears are found only in certain parts of the arctic regions or why malaria-causing mosquitoes flourish in damp and warm areas. Scientists also study spread of disease in animals, plants, and humans by finding the source of that disease, to gain knowledge about the preservation of rare species that may have special needs, and to get informed about the changing geography of the world. For solving these problems, a scientist needs to identify the specific climates, foods and geographic features that different organisms acquire.

2- Biochemistry:

      Biochemistry is concerned with chemical substances and processes that occur in organisms. It involves the structural analysis of the organic compounds that make up cells and of those that play key roles in chemical reactions of life (e.g. photosynthesis and respiration reactions).3- Biostatistics or Biometry:

       Biostatistics is the application of statistical and mathematical formulas in the study of biology. It involves the design, analysis, and interpretation of research data.

  Nowadays it is a necessary field because after solving the biological problems results are usually presented statistically.

Example: 

 Use of mean, median and mode are simple statistical formulas used in biostatistics.

Q.2) Define biology. How can you describe your own body under different branches of biology?

Answer: Biology:

  “Biology is the branch of science which deals with the study of life.”

 The word biology is derived from two Greek words “Bio” means ‘life’ and “Logos” means ‘to study’. In 1736, a Swedish Scientist Carl Linnaeus for the first time used the word biology.

  Zoology is the study of animals e.g., human beings and all living beings. In zoology, I can study my body morphology, anatomy, histology, physiology, embryology, cell biology, immunology, genetics, biotechnology, and pharmacology.

  Biology has recently acquired new technological and conceptual tools to investigate, model and understand living organisms at the system level under the field of biotechnology.

  The bodies of all living things are made of different parts organized in a certain manner that supports life functions. This organization includes:

  Atoms → molecules → organelles → cells → tissues→ organs→ organ system→organisms

• My body is made up of millions of cells. The cell is the structural and functional unit of the human body. When we study cells in a human body it is called cell biology.
• If I study, the structure, form, and shape of my body. It is called morphology.
• If I study the internal structure of my body like studying my digestive system or nervous system. This field of study relates to the field of anatomy.
• When I study the endocrine and nervous systems of my body and how it functions. It belongs to the field of physiology.
• If I study the trait of my height or skin colour. This study belongs to the field of genetics.
• If I am suffering from a fever and needs to know the reason behind it and how to recover from that disease. This study relates to the field of immunology.
• After having a disease when I take medicines to recover from that disease. This belongs to the field of pharmacology.

Q.3) Enlist the various levels of biological organization and explain it with an example.

Answer: Levels of Biological Organization:

  Millions of organisms are present on the Earth. They are different from each other and range from the simplest organisms i.e. bacteria to the most complex ones i.e. human beings.

  The bodies of all living things are made of different parts organized in a certain manner that supports life functions. This organization includes:

     Atoms → molecules → organelles → cells → tissues→ organs→ organ systems →organisms

1- Level 1: Sub-atomic particles and atoms: 

       The living and non-living matter is composed of simple units called atoms. Each atom is further composed of sub-atomic particles (electrons, protons, and neutrons). The bodies of organisms are made of 16 kinds of elements. These elements are called bio-elements. Out of these bio-elements:

•  Only six (O, C, H, N, Ca and P) makes 99% of the protoplasm
• Other 10% includes K, S, Cl, Na, Mg, Fe, Cu, Mn, Zn and I collectively make 1% of the protoplasm.
  

Level 2: Molecules and compounds:

  The atoms combine through bonds and form molecules and compounds. Similarly, the atoms of bioelements combine to form biomolecules.

Types of biomolecules:

  There are two types of bio-molecules.

i-  Micromolecules:

       The bio-molecules with low molecular weight are called micro-molecules e.g. water, amino acids, glucose etc

ii- Macromolecules:

        The bio-molecules with higher molecular weights are called macro-molecules e.g. starch, protein, lipids etc.

Level 3: Organelles: 

  Different bio-molecules combine together in a specific manner and form sub-cellular structures called organelles e.g. mitochondria, chloroplast, ribosome etc. Each organelle performs a particular function.

 For example, mitochondria provide energy to the cell and ribosomes prepare proteins.

Level 4: Cells: 

   The cell is the basic structural and functional unit of an organism. It consists of many organelles such as, Golgi bodies, mitochondria, lysosomes etc. which perform different specific functions inside the cell.

  In unicellular organisms, a single cell makes the whole body. While in multicellular organisms, there are more levels of biological organization.

Level 5: Tissues:

   In multicellular organisms, the cells which are similar in structure and perform similar functions make groups. Such groups of cells are called tissues.

Example:

  In plants, mesophyll tissue is made of cells which perform photosynthesis. In animals, glandular tissue is made of cells which produce secretions.

Level 6: Organs: 

 Different tissues work together to perform a specific activity. Such a group of related tissues is called an organ.

Example:

  The organ stomach is made of two major tissues. Its epithelial (glandular) tissue secretes gastric juice for the digestion of proteins while its muscular tissue contracts and grinds food.  

Level 7: Organ Systems: 

  The organs, in turn, coordinate and constitute an organ system which performs a particular function e.g. blood circulatory system in animals. The blood circulatory system is composed of organs like the heart, arteries, veins, and capillaries.

Level 8: Organism:

   Different organ systems then collectively form a whole organism. In the case of man, different organ systems such as blood circulatory system, respiratory system, digestive system etc. work in coordination. Similarly, in plants, root and shoot systems constitute plant body.

Q.4) Explain the role of bio-elements for living organisms.

Answer: Bioelements:

  The living and non-living matter is composed of simple units called atoms. Each atom is further composed of sub-atomic particles (electrons, protons, and neutrons). The bodies of organisms are made of 16 kinds of elements. These elements are called bio-elements.

1- Primary bio-elements: 

The atoms that make up all living things mostly consist of six different chemical elements: carbon (C), oxygen (O) hydrogen (H), nitrogen (N), phosphorus (P) and sulfur (S). These elements constitute more than 99% of the matter found in living things. They are called primary bio-elements.

1- Carbon (C):

  Carbon is the main bio-element that constitutes the biomolecules. It has the ability to assemble to form large carbon-carbon chains through single, double or triple bonds, as well as cyclic structures. The carbon atom is probably one of the most important bio-elements since all biomolecules contain carbon.

2- Hydrogen (H):

       Hydrogenis one of the components of the water molecule, which is essential for life and is part of the carbon skeletons of organic molecules.

For example:

  Fatty acids have more electrons than carbohydrates, so they have the ability to produce more energy when they degrade.

3- Oxygen (O):

  Oxygen is the other element that makes up the water molecule. It is a very electronegative element that allows greater production of energy through aerobic respiration.

4- Nitrogen (N):

      Nitrogen is the element that is present in all amino acids. Through nitrogen, amino acids have the ability to form a peptide bond to produce proteins. This bio element is also found in the nitrogenous bases of nucleic acids. It is eliminated by the organism in the form of urea.

5- Sulfur (S):

Sulfur is a bio-element that is an essential part of amino acids which form proteins. 

2- Secondary Bioelements:

Other 10% includes K, S, Cl, Na, Mg, Fe, Cu, Mn, Zn and I collectively make 1% of the protoplasm. These types of elements are also present in all living things but not in the same quantities as the primary elements. They do not form biomolecules but are used in cell concentration gradients, dielectric signaling of neurons and neurotransmitters, stabilize charged biomolecules such as ATP and are part of bone tissue.

  These bio-elements are calcium (Ca), sodium (Na), potassium (K), magnesium (Mg) and chlorine (Cl). The most abundant are sodium, potassium, magnesium, and calcium.

1- Calcium (Ca):

Calcium is essential for living things because plants require calcium to build cell walls. It is an integral part of the human skeleton. Calcium affects muscle neuromuscular excitability (along with K, Na, and Mg ions and participates in muscle contraction.)

2- Magnesium (Mg):

       Magnesium is a secondary bio-element that is part of biomolecules since it is a cofactor of chlorophyll. It is present in the skeleton (70%) and in the muscles of animals.

3- Sodium (Na):

      Sodium is an important extracellular cation, participates in the homeostasis of the organism.

4- Potassium (K):

Potassium participates in the homeostasis of the organism and in the propagation of the nervous excitation by channels of potassium.

5- Chlorine (Cl):

       Chlorine is present in the organism of living beings mainly as chloride ion.

6- Trace elements:

       They are present in some living beings. Many of these trace elements act as cofactors in the enzymes. The trace elements are boron (B), bromine (Br), copper (Cu), fluorine (F), manganese (Mn), silicon (Si), iron (Fe), iodine (i)>

Q.5) Who classify the living organisms into five kingdoms. Explain each kingdom with the living organisms included in it.

Answer: Five Kingdoms system:

  Robert Whittaker in 1968 classified all living organisms into five kingdoms. This is known as five kingdoms system of classification. These five kingdoms are;

1. Kingdom Prokaryotae

2. Kingdom Protoctista

3. Kingdom Fungi

4. Kingdom Plantae

5. Kingdom Animalia

1. Kingdom Prokaryotae (Monera):

      This kingdom includes all unicellular and microscopic organisms. These organisms lack a membrane-bounded nucleus and other organelles inside their cells. Their cell wall is made of murein.

Examples:

   Bacteria and Cyanobacteria.

2. Kingdom Protista or Protoctista:

      This kingdom included eukaryotic organisms which are usually small and having differences with the organisms of other eukaryotic kingdoms. They usually live in aquatic habitats.

Example:

  Algae, slime molds, protozoans (Plasmodium, Amoeba, and Paramecium) are some of the examples of this kingdom.

3. Kingdom Fungi:

      Fungi include organisms which are all eukaryotic and multicellular. Their cell wall is made of chitin (a polysaccharide). They do not have chloroplast, so they cannot synthesize their own food and are therefore heterotrophic. The food is stored inside the body in the form of glycogen.

Example:

  Some of the examples are Mushrooms, Molds, Puffballs, yeast etc.

4. Kingdom Plantae:

     This kingdom includes multicellular and eukaryotic organisms which are autotrophic in nature. Their cell wall is made of cellulose and mostly lack centrioles inside their cells. The reserve food in the form of starch.

Examples:

   Brassica, Mulberry, Pinus, Ferns etc.

5. Kingdom Animalia:

    This kingdom includes multicellular and eukaryotic organisms which are heterotrophic in nature. These organisms lack the cell wall and centrioles are present in the cells. The reserve food is in the form of glycogen. The members of this kingdom can be split into two groups that are vertebrates and invertebrates.

Example:

  Animals include jellyfish, worms, insects, fish, reptiles, birds, mammals etc.