Cell — The Structure and Functions

1. Nucleolus
2. Leukoplasts
3. Cellulose
4. Chromoplasts
5. Photosynthesis

1. Cytoplasm
2. Nucleoplasm
3. Chloroplasts
4. Cell Membrane or Plasma Membrane
5. Gene

Nucleus is a small spherical mass mostly located towards the centre of the cytoplasm. Nucleus has the following parts:

1. A delicate, porous nuclear membrane which encloses a relatively dense Nucleoplasm.
2. Inside the nucleoplasm the small darker body Nucleolus is present. The nucleoplasm contains chromosomes.

Below diagram shows the structure of the Nucleus:

The two functions of nucleus are:

1. It regulates and coordinates various life processes of the cell.
2. It plays an important role in cell division.

Robert Hooke is the scientist who coined the term "cell". He used two lenses in his microscope. Under his microscope, he examined a very thin slice of a dead cork (the bark of the trees) and observed a cluster of box-like cubicles piled up together.

The three essential parts of the cell are:

1. Cell membrane
2. Cytoplasm
3. Nucleus

Structure of Cell Membrane:

1. The each cell is surrounded by a cell membrane, also called plasma membrane.
2. It is very thin, delicate and flexible.
3. It is a living structure present in both animal and plant cells.
4. It has fine pores in it, through which only certain substances can pass in and out, while others cannot. Therefore, the cell membrane is called selectively permeable.

Cell division is the necessity for the existence of all living organisms, including plants. This is because new cells need to be produced for-

1. Replacement
2. Repair
3. Reproduction
4. Growth

1. The given diagram shows human cheek cells.

2. The guidelines 1 to 3 are:
   1 → Cytoplasm
   2 → Nucleus
   3 → Cell Membrane

3. 2 → Nucleus

4. Methylene blue stain.

5. 23 pair of chromosomes are found in the part 2, i.e., Nucleus.

1. The given diagram shows an Animal cell. It does not have a cell wall and plastids. Also, the vacuoles are small, unlike the big ones present in a plant cell.

2. The guidelines 1 to 8 indicate:
   1 → Cell Membrane
   2 → Centrosome
   3 → Cytoplasm
   4 → Nucleus
   5 → Nucleolus
   6 → Chromosomes
   7 → Mitochondria
   8 → Vacuole

3. Vacuoles are present in both plant and animal cells. They are larger in size in plant cells, but smaller in size in animal cells.

4. Part 4 is Nucleus. Its protective membranous covering is called Nuclear membrane.

5. Two organelles are — mitochondria and endoplasmic reticulum.

Plastid

Reason — Plastids contain pigments.

Nucleus

Reason — Nucleus is the most important part of the cell. It regulates and coordinates various life processes of the cell.

Red blood cell

Reason — Red blood cell are spherical in shape and this specific shape enables them to hold more oxygen and easily flow through vessels and capillaries.

Cell sap

Reason — Vacuoles are filled with water and various substances in solution from called cell sap.

Compound microscope

Reason — The type of microscope that we use in our school laboratories these days is the compound microscope.

A single biconvex lens

Reason — Antonie Van Leeuwenhoek developed a simple microscope using only a single biconvex lens.

Spirogyra

Reason — Spirogyra is a multicellular green algae.

Plasma membrane

Reason — Each cell is surrounded by a cell membrane, also called plasma membrane. It is the outermost layer.

23 pairs

Reason — Every cell of the human body has 46 chromosomes which occur in 23 pairs.

Vacuoles

Reason — Vacuoles are the non-living inclusions in the cytoplasm bound by a membrane. These are filled with water and various substances in solution form called cell sap.

1. Antonie Van Leeuwenhoek
2. Robert Hooke

The Scientist who invented the first microscope is Antonie Van Leeuwenhoek.

Robert Hooke coined the term "cell".

The three essentials parts of the cell are Cell membrane, Cytoplasm and Nucleus.

1. Cell membrane — Each cell is surrounded by a membrane which is called cell membrane. It is a living structure that is very thin, delicate and flexible. It has fine pores in it, through which only certain substances can pass in and out while others cannot. Therefore, the cell membrane is called selectively permeable.
2. Cytoplasm — The cytoplasm is a semi-liquid, colourless, and translucent substance. It is found between the nucleus and the cell membrane.
3. Nucleus — Nucleus is a small spherical maas mostly located towards the centre of the cytoplasm. It is the most important part of the cell. It regulates and coordinate various life processes of the cell. It plays an important role during cell division.

The cell membrane is called selectively permeable because it allows only entry of specific substances, while holding back the others.

Difference between Nucleus and Nucleolus:

Difference between Cytoplasm and Protoplasm:

Difference between Cell Wall and Cell Membrane:

Difference between plant cell and animal cell:

The Nucleoplasm of the nucleus contains chromosomes. Chromosomes contain units called Genes. These genes are responsible for transmitting characteristics from parents to offsprings. Thus, the chromosomes are extremely important for an organism.

1. The cell is the structural unit of all living things.
2. All cells arise from pre-existing cells.
3. Animals cells have no cell wall.
4. Plastids contain pigment.
5. Vacuoles are filled with water and dissolved substances.

The hidden four cell organelles are:

1. Vacuole
2. Leucoplast
3. Chromoplast
4. Plastid

The solved maze is shown below:

1. Cell Membrane, Cytoplasm, and Nucleus
2. Chloroplasts, Chromoplasts, and Leukoplasts
3. Nuclear membrane, Nucleoplasm, Nucleolus, Chromatin Network, Nuclear Pore
4. Cell Wall and Plastids
5. Freely Permeable membrane (Cell Wall) and Selectively permeable membrane (Cell Membrane)

1. Nerve cells conduct messages in the form of impulses between different parts of the body and the brain.
2. Genes are responsible for transmitting characteristics from parents to offsprings.
3. Leukoplasts store starch, fats and proteins in plant cells.
4. Muscle cells are responsible for movement of body parts. It is the ability of the muscle cells to contract and relax.
5. Nucleus regulates and coordinates various life processes of the cell.

1. Cell — A cell can be defined as the basic structural and functional unit of all living things.
2. Cytology — Cytology is the study of cells, encompassing their structure, function, and interactions with their environment.
3. Protoplasm — Protoplasm is the living substance of the cell. It is made up of the cytoplasm and nucleus.
4. Cytoplasm — The cytoplasm is a semi-liquid (viscous), colourless and translucent substance. It is found between the nucleus and the cell membrane.
5. Chloroplast — Chloroplasts are green plastids, that trap the solar energy for photosynthesis.