Cell - The Unit of Life

cell division

During ________ the chromatin fibers become thick and ribbon- like.

Rudolf Virchow

________ in l858 made an addition to the cell theory by saying that all cells arise from pre- existing cells.

Chloroplasts

________ contain DNA and have the capacity to divide.

Flowers

________ attract insects by thief color contained in the petal cells, or by nectar secreted by the cells.

Hooke

________ examined a thin slice of cork under his microscope and observed that it was made of tiny "box- like "compartments piled up together.

Nucleus

________ is a small spherical mass located somewhat in the center of the cytoplasm.

Mitochondria

________ are the sites where cellular respiration occurs to release energy.

Chromosomes

________ are made of chromatin, which is composed of hereditary units called genes.

functional unit

The cell is the fundamental structural and ________ of all living beings.

endoplasmic reticulum

The ________ (ER) is so fine in the structure that its existence is revealed only through an electron microscope.

irregular network

It is a(n) ________ of double membranes distributed over the entire cytoplasm in a cell.

tubular structures

The Golgi complex consists of many small groups of hollow ________ with membranous walls and is associated with some minute vesicles and vacuoles.

body heat

We maintain our ________ (thermo- regulation) by cellular activity and we cool it when hot by sweating from gland cells in the skin.

Vacuoles

________: These are certain clear spaces in the cytoplasm.

cytoplasm

The ________ is a semi- liquid substance.

Granules

________: There are many small particles in the cytoplasm, these particles are believed to contain food materials, such as starch, glycogen and fats.

Robert Hooke

________ (1635- 1703), an English scientist, developed a microscope by using two lenses for achieving greater magnification.

Lysosomes

________ are small vesicles of different shapes containing some digestive enzymes.

human body cell

Every ________ has 46 (23 pairs) chromosomes.

Respiratory gases

________ are transported from the lungs to other parts of the body by blood cells.

spindle fibers

It is a clear area of cytoplasm close to the nucleus, (from which ________ develop during cell division both in mitosis and meiosis)

Matthias Schleiden

In 1838, ________, a German Botanist, announced that every plant is made up of a large number of cells.

Plastids

________ are found only in plant cells.

Multi

________- celled: Most plants and animals we see around us including ourselves, are made up of millions and billions of cells.

Golgi apparatus

The ________ occurs in the form of granules, filaments, or rods which are supposed to be originated from the endoplasmic reticulum.

centrosome

A(n) ________ is found only in an animal cell.

reproductive tract

The white (albumen) of the egg and the egg- shell are extra parts added to the actual egg as it passes down the ________.

independent existence

It is the smallest part of the body of an organism that is capable of ________ and of performing the essential functions of life.

Extra food

________ is stored as fat in fat cells and as glycogen in liver cells.

ribosomes

The ________ are numerous small granules either scattered freely in the cytoplasm or attached to the membranes of the endoplasmic reticulum.

Dutch

The first microscope was constructed by ________ scientist Antony van Leeuwenhoek (1632- 1723)

mango seed

The ________ had an embryo that also started as a single cell in the ovary of the flowers of the parent mango tree.

nuclear material

They have ________ called chromatic fibers which occur freely in the cytoplasm.

sensitive plant

The drooping of leaves of the ________ on touching and their subsequent recovery to stand out is due to the activity of the cells at the base of the leaves.

ordinary compound microscope

The ________ uses light which is bent by glass lenses to magnify the image while the electron microscope uses beams of electrons that are bent by magnets.

Genes

________ are made of a complex chemical substance DNA (deoxyribonucleic acid)

composition of protoplasm

It varies a little from one cell to another, although the common elements included in the ________, such as carbon, hydrogen, oxygen, nitrogen, sulphur, iron and phosphorus, are the same in all cells.

number of chromosomes

The ________ is definite in each species.

units of structure

He declared that all animals and plants are composed of cells, which serve as the ________ and function.

Structural Unit

________- If we take any part of the body of a frog or any part of a mango plant and examine it under a microscope, it will show a cellular structure.

colorless plastids

Leucoplasts: (leuco: white) are ________.

single cell

The egg was a(n) ________ produced by the cells of the ovary of the mother frog.

Sensory cells

________ on the tongue taste the food and muscle cells of the jaws and of the tongue help in chewing and swallowing.

Cells

________ are so small (microscopic) that they can not be seen with the naked eye.

stem cells

The ________ conduct the food and water to different parts of the plant.

animal cell

A(n) ________ does not have such prominent vacuoles, and the vacuoles are fewer in number.

blood cells

Human red ________ are circular and biconcave, to pass through narrow capillaries and transport oxygen.

Muscle cells

________ are long and contractile to pull or squeeze the parts.

movements of roots

In plants, the bending ________ towards water or gravity, or movements of stems towards light or away from gravity are due to the activities of cells (unequal growth in the cells)

Chloroplasts

________ are abundant in parts exposed to light, e.g.

Structural Unit

If we take any part of the body of a frog or any part of a  mango plant and examine it under a microscope, it will show a cellular structure

Functional Unit

Any function in the body of the frog or in the mango plant is due to the activity in its cells

Cells die and are replaced

The body of the frog, or of the mango tree, is composed of millions and millions of cells

All life starts as a single cell

The life of the frog and the life of the mango tree started as an egg and as a seed respectively

Single-celled

Many small plants and animals are made up of just one single cell

Examples

Bacteria, yeast, amoeba

Few-celled

Some very small plants and animals are made up of relatively few cells-just a few hundred or a few thousand cells

Examples

Spirogyra, Volvox

Multi-celled

Most plants and animals we see around us including ourselves, are made up of millions and billions of cells

Examples

Human beings, Mango

The smallness of Cells

A Greater Efficiency

Cell organelles (the ‘little organs")

Most parts of a cell have a definite shape, a definite structure, and a definite function

The mitochondria *(*mitochondrion) are spherical, rod-shaped, or thread-like {mitos

thread) bodies

Chloroplasts

(chloro green)

Granules

There are many small particles in the cytoplasm, these particles are believed to contain food materials, such as starch, glycogen and fats

Vacuoles

These are certain clear spaces in the cytoplasm

Example

bacteria

Example

all organism other than bacteria

For example

Animals walk, run, jump, swim or fly with the help of muscles (contractile cells) which move the bones (formed of cells and cell secretions)