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Solutions for Biology, Class 7, ICSE
Differences between Monera and Protista on the basis of nucleus:
Monera | Protista |
---|---|
They have no nucleus. They have a poorly developed nucleoid which contains the genetic material. | They have a well-developed nucleus bound by a nuclear membrane. |
Differences between Algae and Fungi on the basis of modes of nutrition:
Algae | Fungi |
---|---|
They have chlorophyll. Thus, they can prepare their own food via photosynthesis. | Due to absence of chlorophyll, they do not prepare their own food. They mostly live on dead, decaying organic matter. |
Differences between Bryophytes and Pteridophytes on the basis of vegetative parts of the plant:
Bryophytes | Pteridophytes |
---|---|
Bryophytes have stems and leaves, but no roots. Instead, they have thread—like structures called rhizoids which stick to the surface and absorb water. | Pteridophytes bear well-formed leaves, stems and roots, but do not produce flowers and seeds. Their leaves produce small rounded bodies on their undersurface. These bodies contain tiny spores which get scattered to produce new plants. |
Differences between Gymnosperms and Angiosperms on the basis of reproductive structures:
Gymnosperms | Angiosperms |
---|---|
Reproductive structures are unisexual cones (male or female) that bear the seeds. | Reproductive structures are unisexual or bisexual flowers. The seeds develop within the female part of the flower, called ovary. |
Differences between Prokaryotes and Eukaryotes on the basis of examples:
Prokaryotes | Eukaryotes |
---|---|
Prokaryotes, like bacteria, lack a nucleus and other membrane-bound organelles. | Eukaryotes, including plants, animals, fungi, and protists, have a nucleus and other membrane-bound organelles. |
Draw a neat, generalized diagram of a bacterium and label its six important parts. Answer the following questions.
(i) Name the kingdom to which it belongs.
(ii) Write two characteristic features of the kingdom.
(iii) Name the gelatinous, proteinaceous covering which surrounds the cell wall.
(iv) Mention two cellular organelles which are absent in bacterium.
(v) Write the scientific name of a comma-shaped bacterium.
The generalized diagram of a bacterium is given below:
(i) Bacterium belongs to Kingdom Monera.
(ii) Two characteristic features of Kingdom Monera are:
(iii) The cell wall is surrounded by a gelatinous or proteinaceous covering called 'capsule'.
(iv) Nucleolus and Mitochondria are two cellular organelles which are absent in bacterium.
(v) The scientific name of a comma-shaped bacterium is Vibrio.
Example- Vibrio cholerae.
Given alongside is the figure of an organism. Study the same and answer the following questions.
(i) Identify the organism.
(ii) Is it a plant/ animal ? Give reason in support of your answer.
(iii) Label the guidelines 1 to 6 shown in the figure.
(iv) Which kingdom does it belong to ?
(v) Write one important role of the parts shown as 3 and 6.
(i) The organism shown in the given figure is Amoeba.
(ii) No, Amoeba is neither a plant nor an animal. Amoebas lack chlorophyll and the ability to photosynthesize, unlike plants. Animals have specialized tissues and organs, which amoebas lack. Hence, Amoeba don't fall under either category.
(iii) The guidelines 1 to 6 are:
1 → Food Vacuole
2 → Nucleus
3 → Pseudopodium
4 → Cell Membrane
5 → Cytoplasm
6 → Contractile Vacuole
(iv) Amoeba is a single-celled organism classified under the Kingdom Protista.
(v) Part 3 (Pseudopodium) — Pseudopodium is the organ of locomotion in an Amoeba. It helps amoeba move in the direction it wants to move in.
Part 6 (Contractile Vacuole) — Excess ammonia (waste) and water gets expelled out of the body of Amoeba from Contractile Vacuole.
Study the figure given alongside and answer the following questions :
(i) Identify the organism. Write its common name as well as scientific name.
(ii) Label the guidelines 1 to 5.
(iii) Which kingdom does it belong to ?
(iv) Write one important role of a part shown as 2.
(v) Mention one very specific feature of this category of plants.
(i) The organism shown in the given figure is Bread Mould (fungi). While it is commonly known as Bread Mould, its scientific name is Rhizopus.
(ii) The guidelines 1 to 5 are:
1 → Spores
2 → Sporangium
3 → Sporangiophore
4 → Rhizoids
5 → Node
(iii) Bread Mould belongs to Kingdom Fungi.
(iv) Sporangium are the spore containing bodies. When the sporangium bursts open, the spores are dispersed into the air. When they land on a suitable substratum, each can grow to form a new mycelium.
(v) This category of plants live on dead, decaying organic matter, so they are called Saprophytes.
Four types of bacteria on the basis of their shape are:
The Bryophytes are found on damp surfaces in moist places. They are called amphibians of the plant kingdom because they need water to reproduce. Like amphibians they need water as well as land to complete their life-cycle.
Amoeba has cell membrane as the outer covering of body. The cell membrane is a flexible structure which enables Amoeba to change its shape. Also, the Amoeba moves by extending the cytoplasm along the cell membrane, forming a finger-like structure known as Pseudopodia.
The contractile vacuole is a vacuole in which the excess of water from the body of the amoeba is collected. The function of the contractile vacuole in Amoeba is excretion. Ammonia is the main waste product of amoeba which dissolves in water and is excreted through the general body surface by simple process of diffusion.
Five uses of Bacteria are:
Five uses of Fungi:
Bacteria are responsible for a number of diseases, some of which are typhoid, leprosy, TB, pneumonia, cholera, etc. They also cause spoilage of food items such as milk, meat, fish and vegetable. Tinned and package food also get spoiled due to bacteria, after their expiry date. Thus, we can say that the bacteria are harmful to human beings.
Binary fission is the process of reproduction in amoeba in which the full grown amoeba splits into two. First the nucleus divides into two, and then the rest of the cell divides in a way that each half gets one daughter nucleus.
The two main categories of plants recognised on the basis of whether they produce fruits or not are:
Answer
Angiosperms and gymnosperms
Reason — Angiosperm are flowering plants that produce fruits while gymnosperms produce only seeds without producing fruits.
Name the following:
Correct the following statements by changing the first/ last word only :
Column A | Column B |
---|---|
(i) Retting | (d) Fibres |
(ii) Tanning | (e) Leather |
(iii) Lactobacillus | (a) Curd |
(iv) Acetobacter | (b) Vinegar |
(v) Biogas | (c) Cowdung |
Given below are sets of four terms. Choose the odd one and write the category for the remaining terms.
Odd one — COVID-19
Category of the remaining terms — Bacterial diseases
Odd one — Bacteria
Category of the remaining terms — Protists
Odd one — Spirogyra
Category of the remaining terms — Fungi
Odd one — Deodar
Category of the remaining terms — Gymnosperms
Odd one — Brinjal
Category of the remaining terms — Monocotyledons
Name the categories of the following:
Column I | Column II |
---|---|
(i) Bread mould | (d) Saprophytes |
(ii) Spirogyra | (a) Has chlorophyll |
(iii) Moss | (e) Has rhizoids |
(iv) Fern | (b) Leaves with spores |
(v) Gymnosperm | (c) Naked seeds |
Classification — Classification is a system of arranging living organisms into groups based on their similarities and differences.
Binary fission — In a full-grown Amoeba, first the nucleus divides into two, and then the rest of the cell divides in a way that each half gets one daughter nucleus. This process is called binary fission.
Pseudopodia — Pseudopodia (meaning false feet) is the organ of locomotion in an amoeba.
Symbiosis — Symbiosis refers to a close and long-term interaction between two different types of organisms. For example, Rhizobium bacteria lives in the root nodules of leguminous plants. These bacteria provide food to the host plant and the host plant in turn provides shelter to the bacteria.
Mycelium — A network of hyphae is called mycelium.
Gymnosperms — Pine and Cedar
Multicellular fungi — Morchella and Agaricus
Monerans — Coccus and Bacillus
Protists — Amoeba and Paramecium
Leguminous plants — Pea and Bean
Typhoid — Salmonella typhi
Tuberculosis — Mycobacterium tuberculosis
Pneumonia — Streptococcus pneumoniae
Cholera — Vibrio cholerae
Diptheria — Corynebacterium diphtheriae