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Cell-Structure and Functions class 8 Short Question and answer

Cell-Structure and Functions class 8 Short Question and answer
Question 1: What is the basic living unit of an organism?
Answer: Cell
Question 2: Name the instrument used to study cells.
Answer: Microscope
Question 3: Name the scientist who coined the term cell.
Answer: Robert Hooke coined the term ‘cell’.
Question 4: What is the meaning of term cell.
Answer: a small room
Question5: Name two unicellular organisms.
Answer: Amoeba and paramecium
Question6: Name two multicellular organisms.
Answer: Humans and cat
Question7: Do all cells have same shape?
Answer: No, they have different shapes.
Question7: What is tissue?
Answer: A group of cells that have similar structure and that function together as a unit is called tissue. Example:- blood, bone, and ligaments etc.
Question8: What is organ?
Answer: A collection of tissues that structurally form a functional unit specialized to perform a particular function. Example:- liver, heart, and lungs etc.
Question 9: Name one cell in human body which is spherical in shape.
Answer: Red blood cells
Question 10: Which cell receives and transfers messages?
Answer: Nerve cell
Question 11: What is the shape of muscle cells?
Answer: Spindle shaped
Question 12: What is the basic similarity among all the living organisms (plants and animals)?
Answer: They are made up of cells.
Question 13: Name the animal cell which is long and has thread like branches.
Answer: Nerve cell (a neuron) is the only animal cell which is long and has thread like branches.
Question 14: A hen’s egg can be seen easily. Is it a cell or a group of cells?
Answer: The egg of a hen represents a single cell and is big enough to be seen by the unaided eye.
Question15: What is the smallest size of cell?
Answer: 0.1 to 0.5 micrometre
Question16: What is the meaning of micrometre?
Answer: 10 lakhs part of a meter
Question17: What is the size of largest cell?
Answer: 170mm * 130mm
Question18: What do you mean by pseudopodia?
Answer: The false feet of Amoeba.
Question19: Name a single cell present in the human body which can change its shape.
Answer: White blood cell
Question20: What is the difference between WBC and Amoeba?
Answer: WBC is a cell were as amoeba is a full-fledged organism.
Question 21: Name one cell which can be seen by unaided eye.
Answer: Some cells are big enough to be seen with the unaided eye. Hen’s egg is an example.
Question 22: Name the outermost layer of an animal cell.
Answer: Cell membrane is the outermost layer of an animal cell.
Question 23: What are the basic parts of a cell?
Answer: The basic components of a cell are cell membrane, cytoplasm and nucleus.
Question 24: What is plasma membrane?
Answer: A layer which enclose cytoplasm and nucleus in it is called plasma membrane or cell memmbrane.
Question 25: What is cell membrane/ plasma membrane made up of?
Answer: The plasma membrane consists of both lipids and proteins.
Question 26: What is lipids?
Answer:Lipids are energy-rich organic molecules, which provide energy for different metabolic activity.
Question 27: What are the functions of cell membrane? Does it have areas from which substance go out.
Answer: The functions of cell membrane are:
  • They enclose cytoplasm and nucleus in it.
  • They membrane seprates cells from one another and also the cell from the surrounding medium.
The plasma membrane is porous and allows the movement of substance bothe inward and outward.
Question 28: What is cell wall?
Answer: In addition to the cell membrane, there is an outer thick layer in cells of plants called cell wall. It gives rigid shape to the cell.
Question 29: Why is cell wall needed by the plant cells?
Answer: This additional layer surrounding the cell membrane is required by plants for protection. Plant cells need need protection against variations in temperature, high wind speed, atmospheric moisture etc.
Question 30: What is cytoplasm?
Answer: Jelly-like substance present between the cell membrane and the nucleus it is called cytoplasm.
Question 31: What is cytoplasm made up of?
Answer: Cytoplasm is made up of water,salts and protein.
Question 32: What is nucleus?
Answer: Nucleus is a spherical organelles located in the center of the cell.
Question 33: What is nuclear membrane?
Answer: Nucleus is seprated from cytoplasm by nuclear membrane. This is also porous and allows the movement of materials between the cytoplasm and the inside of the nucleus.
Question 34: What is nucleolus?
Answer: The nucleolus is a spherical structure found in nucleus whose basic function is to assemble and produce the cell's ribosomes.
Question 35: What are chromosomes?
Answer: Nucleus contains thread-like structures called chromosomes. These carry genes and help in inheritance or transfer of characters from the parents to the offspring.
Question 36: What are genes?
Answer: Gene is unit of inheritance in living organisms. It controls the transfer of a hereditary characteristic from parents to offspring. Genes are also called as DNA - Deoxyribonucleic acid.
Question 37: Write the functions of Nucleus?
Answer: Nucleus, in addition to its role in inheritance, acts as control center of the activites of the cell.
Question 38: What is protoplasm?
Answer: The entire content of a living cell is known as protoplasm. It includes the cytoplasm and the nucleus. Protoplasm is called the living substance of the cell.
Question 39: What are prokaryotic cells?
Answer: The cells having nuclear membrane are termed as prokaryotic cells. The organisms with these kinds of cells are called prokaryotes (pro: primitive; karyon:nucleus). Example:- bacteria and blue green algae.
Question 40: What are eukaryotic cells?
Answer: The cells, like onion cells and cheek cells having well-organised nucleus with nuclear membrane are designated as eukaryotic cells. All organisms other than bacteria and blue green algae are called eukaryotes. (eu:true; karyon:nucleus).
Question 41: What is vacuole?
Answer: Vacuoles are membrane bound transparent organelle present in both animal and plant cell. They have sac-like structure which stores salts, minerals, pigments and proteins which is called cell sap.
Question 42: How are the vacuoles in animal and plant cells different?
Answer: Plant cell has a big central vacuole unlike a number of small vacuoles in animal cells. It is temporary in animal cell and permanent in plant cell.
Question 43: What are Plastids?
Answer: Plastids are double-membrane organelles which are found in the cells of plants and algae. They are of different colours.
Question 44: What do chloroplasts contain?
Answer: Chlorophyll
Question 45: Name the organelle of a plant cell where photosynthesis takes place.
Answer: Photosynthesis takes place in chloroplasts, which contain the chlorophyll.


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