cells

Question 1

prokaryotic cell

Answer 1

lack many membrane bounded organelles such as Mitochondria, Endoplasmic reticulum, Chloroplast and Golgi Apparatus (trick: mec-g)

Question 2

Ribosomes

Answer 2

prokaryotes: 70s (small)
eukaryotic: 80s (large)

Question 3

prokaryotic cell

Answer 3

• mitosis & meiosis is missing so binary fission takes place in cells
  -have no true nucleus so dna scatter in the cytoplasm
• chromosomes is formed of only dna
• cell wall is made of peptidoglycan and murein
  -Average diameter 0.5 – 20 μm of cell

Question 4

eukaryotic cells

Answer 4

• its flagella and cillia are made up of microtubules
• a typical cell’s size is 10 - 100um
• chromosomes is made up of dna and protein
  -plant cell wall made of cellulose and fungi cell wall is made of chitin
  -Complex, with 9 + 2 arrangement
  of microtubules intracellular,200 nm diameter

Question 5

Microscope

Answer 5

• The discovery of cells and their structures become possible with the development of optical lenses and with construction of compound microscope ( mikros- small, skopein- to see, to look)
• Which was invented by David Jensen in 1590 and in 1610 Galileo an Italian astronomer and physicist designed it properly

Question 6

Cell (greek, kytos- cell; la; cella- hollow space

Answer 6

• It was discovered by Robert hooke in 1665
• Schwann after finding nucleus in the centre of the cell nucleus surrounded by a fluid in the cell his observation changed the definition of cell it described that
  “cell as a structure which consist of nucleus surrounded by semi fluid substance in closed by a membrane”

Question 7

Amount of cell

Answer 7

• When Robert hook first discovered the cell as a basic unit of life in 1663 he calculated over 1 billion of cells in a cubic inch of cork.
  Some of the people have done research on the no of cells in a way that
• A newborn human baby contain two trillion cells.
• An adult 16 trillion when you donate blood.
• When you donate blood, you give away 5.4 billion cells.
• Each day infact a human body sloughs off and replaces 1 percent of its cells or about 600 billion

Question 8

Nucleus

Answer 8

• ## Discovered by Robert Brown (1831)

Question 9

Emergence of cell theory

Answer 9

In 1838 schleiden a German botanist concluded that despite differences the structure of various tissues and plants were made of cells, in 1839 a German biologist T. Schwann published the comprehensive report on cellular basis of animals, in 1855 Rudolf Virchow a German pathologist had made a convincing case and added third point to the cell theory:
1. All organisms are composed of one or more cells.
2. The cell is the structural and functional unit of life.
3. Cells can arise only by division of pre existing cells it is not a ‘denovo’ structure.

Question 10

Vacuoles

Answer 10

• Generally vacuoles (except food vacuoles) are non protoplasmic liquid filled cavities in the cytoplasm
• Surrounded by a membrane called tonoplast (selectively permeable)
• The vacuoles in plant cells are filled with cell SAP and act as store house which often place role in plant defence. Plant vacuoles sometimes act as lysosome as they contain hydrolytic enzyme after death cells tonoplast lose its differential permeability and its enzyme causes lysis of these cell.
• In animal cells lysosomes are which in hydrolytic enzyme including proteases, ribonucleases and glycosidase.

Question 11

Cell membrane

Answer 11

Plasma membrane or cell membrane is the outer most boundary of the cell. However, in most plant cells, it is covered by a cell wall.
Structure
Under electron microscope it is a bi-
layered structure, this structure is
delicate and elastic it has some ability
to repair itself.
Models of Cell Membrane Structure
There are two models of cell
membrane structure:
Unit Membrane Model According to
this model the cell membrane
is composed of lipid bilayer
and sandwiched between two
protein layers. This structure is
present in all cell organelles
(for example, mitochondria,
chloroplast etc.)
Fluid Mosaic Model According to the fluid mosaic model the cell membrane consists of a double
layer of phospholipid molecules, known as a lipid bi-layers. It has proteins and other molecules.
The name fluid mosaic is used because the bi-layer is a very fluid structure and it contains a mosaic
of protein molecules.
Chemical Composition
Cell membrane contains phospholipids 20-40% proteins, 60-80% cholesterol and
polysaccharides.
• It is about 7 nm thick
• The basic structure is a phospholipid bilayer.
• The hydrophilic phosphate heads of the phospholipids face outwards. The result is the
aqueous environment inside and outside the cell.
• The hydrocarbon tails face inwards and create a hydrophobic interior.
• Most protein molecules float about in the phospholipid bilayer forming a fluid mosaic pattern.
• The proteins stay in the membrane because they have regions of hydrophobic amino acids
which interact with the fatty acid tails to exclude water.
• Some proteins and lipids have short branching carbohydrate chains like antennae forming
glycoproteins and glycolipids respectively.
• Membrane also contains cholesterol. Like unsaturated fatty acids cholesterol disturbs the
close packing of phospholipids and keeps them more fluid. This can be important for
organisms living at low temperatures when membranes can solidify. Cholesterol also
increases flexibility and stability of membranes, without it membrane break up.
• The two sides of a membrane differ in composition and function.
Functions of Membrane
• The phospholipid bilayer provides the basic structure of membrane. It also restricts entry and
exit of polar molecules and ions.
• Channel protein and carrier proteins are involved in the selective transport of polar
molecules and ions across the membrane.• Some proteins act as receptor molecules for chemical signaling between
cells.
• Some proteins act as an antigen these act as cell identity markers.
• Glycolipids and glycoproteins help cells to recognize each other – allowing
the immune system to tell the difference between body cells and invading
bacteria.
• Energy transfer ion photosynthesis and respiration proteins take part in the
energy transfer system.

Question 12

Imp points 1

Answer 12

•diffusion
and passive transport are the two names of the same process
•ER with no ribosomes attached
is known as SER.
Smooth ER is not involved in
protein synthesis but is the site
of steroid (lipid hormone)
production. It also contains
enzymes that detoxify, or
make harmless, a wide variety
of organic molecules, and it
acts as a storage site for
calcium in skeletal muscle
cells.
•Discovery of cell is linked with the
invention of microscope because most of the cells are microscopic
Jean Baptist de-Lamarck (1809) said
“nobody can have life if it is not
formed by cellular tissue.”
•Robert Brown said that nucleus is
present in the cell and the cell is not
an empty space. He discovered the
nucleus in the cells of orchids.
•Lorenz Oken in 1805 (a German
scientist) said “all living beings
originate from or consist of vesicles or cells”.
•A cell is the structural and
functional unit of life
•Louis Pasteur (1862)
said that bacteria
are formed from
existing bacteria.
•Jean Baptist de-Lamarck (1809) said
“nobody can have life if it is not
formed by cellular tissue.”

Question 13

Diffusion

Answer 13

Diffusion is the movement of molecules
or ions from a region of their high
concentration to a region of their low
concentration. The process is passive
(does not require energy and happens
spontaneously).
Two factors affect the rate of diffusion
a) Difference in concentration between
point A and point B. The steeper the
gradient, the faster the rate of diffusion.
b) The greater the surface area of a
membrane through which diffusion is
taking place the greater the rate of
diffusion.

Question 14

Facilitated Diffusion

Answer 14

Some substances enter and leave cells
much faster than you would expect it
only diffusion occurred. We now know
that some membrane proteins facilitate
the diffusion of some substances across
the cell membrane.
Two types of proteins are responsible
for facilitated diffusion.
• Specific carrier protein takes
particular substance from the
membrane to the other.
• Ion channels are proteins that
open and close to control the
passage of selected charged
articles.
• Channel proteins have a fixed
shape

Question 15

Osmosis

Answer 15

Osmosis is a passage of water molecules from a region of their high concentration to a
region of their low concentration through a partially permeable membrane. We can say
that it is a form of diffusion in which only water molecules move.

Question 16

Active Transport

Answer 16

Active transport is the energy-consuming transport of molecules or ions across a
membrane against a concentration gradient. Movement are usually in one direction only.
Unlike diffusion which is reversible. The energy is supplied in the form of ATP made in
respiration. Without respiration, active transport is therefore impossible.

Question 17

Endocytosis and Endocytosis

Answer 17

• Endocytosis and exocytosis are active processes involving the bulk transport of
materials through membrane, either into cells (endocytosis) or out of cells
(exocytosis).
• Endocytosis occurs by an enfolding or extension of the cell membrane to form a
vesicle it is of two types.
o Phagocytosis (cell eating) material taken up is in solid form. Cells
specializing in the process are called phagocytes and are said to be
phagocytic. For example, some white blood cells take up bacteria by
phagocytosis. The sea formed during uptake is called a phagocytosis
vacuole.
o Pinocytosis (cell drinking) material taken up is in liquid form. The vesicles
formed are often extremely small, in which case the process is known as
micropinocytosis and the vesicles as micro pinocytosis vesicles.
• Exocytosis is the reverse process of endocytosis. Waste materials may be
removed from cells, such as solid, undigested remain from the pancreas is
achieved in this way. Plant cells use exocytosis to export the material needed to
form cell walls.

Question 18

The Nucleus

Answer 18

§ The nucleus is the largest and most prominent organelles in the animal cell.
§ Almost all eukaryote cells have a nucleus – red blood cells in mammals and phloem cells
in plants are exception.
§ Every nucleus is surrounded by a nuclear envelope. This consists of two membranes that
are separated by gap of 20 to 40 nm.
§ Nucleus may be irregular in shape and about 10 µm in diameter. It contains the cell’s DNA,
which carries information that allows the cell to divide and carry out all its cellular
processes.
§ Nucleus controls the life and activities of the cell.
§ In animal cells nucleus is generally present in the central part. In plant cells nucleus is
pushed towards periphery due to a large central vacuole.
§ DNA/RNA and proteins (including
enzymes) forms the chemical
composition of coleus.
§ Nucleus consists of nuclear
membrane, nucleoli, nucleoplasm
and chromosomes.
§ The number of nuclear pores is
highly variable. For example, the
undifferentiated cells (e.g. eggs)
have many pores (about 30000 per
nucleus) while the differentiated
cells (e.g. erythrocytes) have only 3
or 4 pores/nucleus. Each pore has a
definite structure.

Question 19

Nucleolus

Answer 19

Nucleolus is a darkly stained structure within the nucleus. It has no membrane.
There are two regions of a nucleolus.
The Peripheral Granular Area
It contains the materials from which ribosomal subunits are formed.
The Central Fibrillar Area
It has large molecular weight RNA and rDNA.
• The heredity material is in the form of chromosomes, which controls all the activities of
the cell. Chromosome is formed of DNA and proteins.
• Nucleus is visible when the cell is in non-dividing stage. It contains chromatin network
and soluble sap called nucleoplasm. Dark staining chromatin, consisting of tightly packed
DNA, is known as Heterochromatin. The lighter, more loosely packed material is called
Euchromatin contains the DNA that is being actively read to produce proteins. In
heterochromatin, the DNA is packed together and is not being read. Nucleus is stainedwith the basic dyes because of the chromatin material. During cell division chromatin
material is converted into darkly stained thread like structures called chromosome.
Chromosome is made of arms and centromeres.
• Centromere is the place on the chromosome where spindle fibers are attached during cell
division.
o Each chromosome consists of two identical chromatids at the beginning of cell
division which are held together at centromere.
• A chromatid is exact replica of the chromosome.
• The information to control cell activities is present on the chromosomes in the form of
genes.
• The chromosome number varies which may be 2n = 2 to 2n = 1200 (Pteridophytes).
• The number of chromosomes in all individuals of the same species remains constant
generation after generation.
• Some examples of chromosome No. are: Frog = 26, Chimpanzee = 48. Fruit fly (Drosophila
melanogaster) = 8, Wheat = 42, Onion = 16, Potato. = 48. Garden pea = 14. Penicillium (a
fungus) has two chromosomes (one pair), corn 20, wheat 42, sugarcane 80, some ferns
have more than 500 pairs, mosquito 6, fruit fly 8, frog 26, honey bee 32, mouse 40 and
human cells have 46 chromosomes (23 pairs).
• The number of chromosomes in normal body cells is diploid (2n) while the gem cells
(sperms and eggs) have haploid chromosome number (11).
Examples
Human germ cells (eggs and sperms) = 23
chromosomes.
Drosophila germ cells = 4 chromosomes.

Question 20

Endoplasmic reticulum (ER)

Answer 20

The nuclear envelope joins with the membrane of the endoplasmic reticulum (ER). It is a system
of complex network spread throughout the cell.
These are present in Eukaryotic cells & are of two types:
1) RER
2) SER
• On the outside surface of the RER are ribosomes.
• The main function of RER is to keep together and transport the proteins made on the
ribosomes.
• Instead of simply diffusing away into the cytoplasm, newly made proteins enter into RER.
Here they fold into three-dimensional shape.
• A mature cell that makes and secretes large amounts of protein – such as one that makes
digestive enzymes – has RER that occupies as much as 90 per cent of the total volume of
the cytoplasm.
• RER is also a storage unit for enzymes and other proteins.Small vesicles containing newly synthesized proteins pinch off from (the ends of the RER
and either fuse with the golgi complex or pass directly to the cell surface membrane.
• The channels having material present in them which is separated from the cytoplasmic
materials by the spherical or tubular membranes is called cisternae.
• E.R provides mechanical support to the cell.
• In some cells SER transmit impulses. For example, nerve and muscle cells.
• Both RER and SER are involved in the transportation of materials from one part of the cell
to the other.

Question 21

Ribosomes

Answer 21

Ribosomes were discovered by Palade in 1955.
§ Ribosomes are small dense organelles, about 20 nm in diameter present in great numbers in
the cell. Most are attached to the surface of RER but they can occur free in the cytoplasm.
§ Ribosomes are made from a combination of rRNA and protein. Eukaryotic ribosomes are
compose-I of an equal quantity of RNA and protein. Therefore, they are also called as
ribonucleoproteins.
§ Ribosomes are involved in protein synthesis. They assemble amino acids in the right order to
produce new proteins. The ribosome uses the code on’ messenger RNA (mRNA) to put amino
acid together in chains to form specific proteins.
§ Generally, proteins that are to be used inside the cell are made on free ribosome while those
that are to be secreted out of the cell are made on ribosomes that are bound to ER
membranes.
§ New ribosomes are formed in the nucleolus.
§ Eukaryotic ribosome is 80 S (60 S + 40 S). Mg++ controls this
attachment.
§ A group of ribosomes attached to the same mRNA are called
polysomes.
Nucleolus is the factory of ribosomes and ribosomes are the factory of protein synthesis

Question 22

The Golgi Complex

Answer 22

The Golgi apparatus/Golgi complex was discovered by Camillo Golgi
in 1898. It is found in eukaryotic cells.
• Golgi apparatus consists of stacks of flattened membrane
• bound sacs or flattened cavities or vesicles called Cisternae (5 – 8).
• The whole organelle is a shifting, flexible structure; vesicles are constantly being added at one
side and lost from the other. Generally, vesicles fuse with the forming face (the one nearest
to the nucleus) and leave from the maturing face (the one nearest to the cell surface
membrane).
• Golgi complex has proteins, carbohydrates, glycoproteins and some enzymes. The Golgi
complex appears to be involved with the synthesis and modification of proteins. lipids and
carbohydrates.
• Major functions of Golgi complex are formation of conjugated molecules and Secretions.
• Proteins made on the ribosomes attached to ER are packaged into the vesicles by the ER.
Some of the vesicles join with the Golgi complex and the proteins they contain are modified
before they are secreted out of the cell.
• Golgi apparatus + Golgi vesicles = Golgi complex
• Secretions are products formed in the cells on ribosomes and then pass to the outside
through endoplasmic reticulum and Golgi apparatus.
• In plants Golgi apparatus is involved in the synthesis of cell wall.

Question 23

Mitochondria

Answer 23

• Mitochondria are important organelles of eukaryotic cells. They manufacture and supply
energy to the cell. Therefore, they are also called powerhouse of the cell.
• Mitochondria are particularly abundant in metabolically active cells, tissues such (is muscle
and tissues involved in active transport.
• The size (0.5 – 1.5 µn wide) and number of mitochondria varies and depend upon the
physiological activity of the cell.
• Under compound microscope mitochondria may be rod shaped, vesicles or filaments. In
Electron Microscope, Mitochondria have two membranes, outer smooth and inner with
aristae.
• The inner surface of aristae in the mitochondrial matrix has small knob like structures called
F1 particles. These are involved in ATP formation.
• Mitochondrial matrix contains enzymes, coenzymes and organic and inorganic salts.
Mitochondria also contain DNA and ribosomes.
• Mitochondrial matrix helps in metabolic processes like Kreb’s cycle, aerobic respiration and
fatty acid metabolism etc. Their main function is to make ATP via the process of aerobic
respiration. ATP diffuses into the cell and provides instant chemical energy.
• Mitochondria have a double membrane; the outer membrane is smooth while the inner one
is folded. This arrangement gives as large internal surface area on which the complex
reactions of aerobic respiration can take place.
Mitochondrion is a self-replicating organelle.

Question 24

Centrioles

Answer 24

Centrioles are present in animal cells, some microorganisms and lower plants. They are absent
in higher plants.
§ Centrioles are short bundles of filaments, set at right angles to each other. They are found in
a clear area of cytoplasm known as the centrosome.
§ In a cross section, each centriole consists of a cylindrical array of 9 microtubules, each
microtubule has 3 tubules. The tubules are composed of special protein caned tubulin. The
chemical composition and structure is similar to that of cilia and flagella.

Question 25

Imp points 2

Answer 25

•Robert Hooke discovered the cell in 1665 under his self-made compound microscope.
According to Hooke, cell is an empty space surrounded by thick walls. He published his -
work in Micrographia in 1665.
•Cell theory is: “All living organisms
are composed of cells and cell
products”.
•A German physician Rudolph Virchow
(1855) said “omniscellula e cellula”
(new cells formed by the division of
existing living cells). It was opposite to the idea of Abiogenesis
•The main features of Cell Theory in its present form are:
- All organisms are composed of one
or more cells.
- All cells arise from pre-existing cells.
- Cell is the basic structural and functional unit for all organisms.
•A German zoologist Theodor Schwann
(1839) and a German botanist Schleiden
(1838) worked independently on the cell
•The human naked eye can
differentiate between two points,
which are 1.0 mm apart. This is
known as resolution of the eye. This
resolution can be increased by
lenses.
•They found that a cell has 3 parts:
Nucleus
Cytoplasm (fluid surrounding the nucleus) and
Plasma membrane (outer thin membrane)
•In a compound microscope the
resolution is 2.0 µm. It is 500 X that
August Weismann (1880) said that
all living cells have a common origin
because they have basic similarity in
structure and cTheir function is the formation of spindle (that guides the chromosomes during cell division). In addition to spindle formation, the centrioles act as the center of formation for the whole cytoskeleton and they are known as
microtubule organizing center composition.
•Their function is the formation of spindle (that guides the chromosomes during cell division). In addition to spindle formation, the centrioles act as the center of formation for the whole cytoskeleton and they are known as
microtubule organizing centers.

Question 26

Imp points 3

Answer 26

The source of illumination in compound
microscopes is visible light. In electron
microscope the source of illumination is
a beam of electrons.
In multi-cellular organisms there is a
division of labour. Examples from animals
are:
Muscle cells contract and relax
Nerve cells transmit impulses
Gland cells secrete
Red blood cells carry oxygen
Some stomach cells secrete gastric juice
White blood cells (WBC) produce
antibodies.
Eye cells detect and respond to light.
The resolution of electron microscope is 2
– 4 Angstrom. It is 500 X greater than that
of the compound microscope and 250,000
X greater than that of the naked eye.
Examples from animals are:
Xylem cells conduct water and mineral salts from
soil to the aerial parts of the plant
Phloem cells translocate
Sclerenchymatous cells give support to the plants
food
Chlorenchymatous cells carry out photosynthesis
Parenchymatous. cells store surplus food and
Meristernatie cells produce new cells for growth
and development of the plant
Due to different functions the cells
have different shapes and sizes.
The function of an organism is due to
activities and interactions of different
cells and cell components.
To study cell parts, modern techniques are used.
Most modern technique is cell fractionation.
The process of grinding to get a uniform
composition/structure is called
homogenization.
The tissues are taken and are
homogenized by special instruments
(like homogenizers).
Cell size is measured in
micrometer (µm). One µm is
0.000,001 meter or 1 x 10 –
6 of a metre.

Question 27

Imp points 4

Answer 27

•The process of separation of different parts of the cell into different
layers (on the basis of their size and weight and density of the
medium) in the centrifuge tube using a centrifuge machine at medium
speed is called density gradient centrifugation.
•The magnification power of microscope is determined by
multiplying X values of ocular lens and X value of objective lens.
For example: A microscope with 10 X ocular lens and 40 X
objective lens will have 10 X 40 = 400 X magnifying power
•In most plant cells, cell
membrane is surrounded by
cell wall.
•Ostrich’s egg is the biggest egg
•The electron microscope has shown
that the cell wall is formed by three main layers:
Middle lamella
Primary cell wall
Secondary cell wall
•A compound microscope has
different magnification powers. The
ocular lenses may he 5 X and 10 X
while objective lenses may be 20 X
•

Question 28

Imp points 5

Answer 28

Primary wall is a true wall and develops in
newly growing cells. It is mainly made up
of cellulose with some deposition of pectin
and hemicellulose.
First of all Middle Lamella is formed between
the primary wall s of the neighboring cells. It is
not the true wall and is composed of pectin or
calcium pectate.
The polysaccharides in bacterial cell wall and
cellulose in plant cell wall are carbohydrates.
Cell wall protects the cell from osmotiolysis.
The protoplasm of a eukaryotic cell is
divided into nucleus and cytoplasm.
Cytoplasm is formed by an aqueous ground substance
which contains:
Many cell organelles
Insoluble wastes and storage products (called inclusions)
Cytosol (the soluble part of cytoplasm is called cytosol)
Cytosol is 90 % water and 10
inorganic and organic molecules.
Cytosol has true solutions and colloidal
solutions. The colloidal solution may be sol or
gel. Sol is non-viscous and gel is viscous.
The material present in between
the plasma membrane and the
nuclear membrane is called
cytoplasm. Cytosol is 90 % water and 10 inorganic and organic molecules
Lysosomes are involved in:
Autophagy/self-eating (Autophagosomes)
Phagocytosis
Extra-cellular digestion and autolysis
The peripheral part of the cell is
like a gel.
The process of separation of different parts of the cell into
different layers (on the basis of their size and weight and
density of the medium) in the centrifuge tube using a
centrifuge machine at high speed is called density gradient
ultracentrifugation.
The free floating cell organelles (e.g.
Mitochondria) move in the cytoplasm
due to cytoplasmic streaming
movements and is called active mass
movement of cytoplasm.
De Duve in 1949 isolated lysosomes. They
are found in most eukaryotic cells
Lysosomes are rich in acid phosphatases and
several other hydrolytic enzymes.
In the primary cell wall the cellulose fibers
are arranged in a criss-cross manner which
give strength to the cell wall.
•The autophagosomes working on digestive
vacuoles are also known as secondary Lysosomes
•The living content of the cell is called
protoplasm
•ondary cell wall is formed on Inner
surface of primary wall. It is thick and rigid
than primary wall. Chemically it is
composed of inorganic salts, silica, wax
•TAY-SACH’S disease is due to the absence of an
enzyme that is involved in the catabolism of
lipids. Accumulation of lipids in brain cells leads to mental retardation and even death.
•De-Duve and coworkers isolated peroxisomes in
1965 from liver cells and other tissues. These are
single membrane organelles (0.5 µm in diameter).
•If an enzyme that breaks glycogen
to glucose is absent from
Lysosomes, the result is a disease
Glycogenosis type II.

Question 29

Imp points 6

Answer 29

Peroxisomes have oxidative enzymes such as
peroxidase, catalase and glycolic acid oxidase etc.
The main protein in cytoskeleton are
tubulin (in microtubules) actin, myosin,
tropomyosin and other which are also
found in the muscles.
Central vacuole is formed by combining the
smaller vacuoles during the growth and
development of plant.
In seeds rich in lipids (such are castor and
beans) glyoxysomes break fatty acids to
succinate.
In lipid-rich seeds (e.g. castor, bean and soybeans
etc.), glyoxysomes are abundant during
germination period. In lipid poor seeds (e.g. pea),
they are absent.
Microfilaments are involved In internal cell
motion also called cyclosis.
Microfilaments are much more slender.
They are made up of contractile actin
protein linked to the inner face of the
plasma membrane.
Microtubules are long, unbranched and
slender structures, they are composed of
tubulin proteins.
The microtubules are joined in a specific way
to form some cell organelles. For examples
cilia, flagella, basal bodies and centrioles etc.
Amoeboid movements are because of
micro filaments.
Intermediate filaments play a role in maintaining
the cell shape and are also involved in the linkage
of the cell parts.
The cytosol contains cytoskeletal fabric
formed of microtubules, microfilaments
and intermediate filaments. This is
Cytoskeleton.
Vacuoles are bounded by a single
membrane (tonoplast)
In plant seedlings, Glyoxysomes convert
stored fatty acids to carbohydrates and
provide energy to grow a new plant. This
process occurs through glyoxylate cycle.
Enzymes of this cycle are present in the
glyoxisomes.
Microtubules Microfilament Cilia Flagella
•Peroxisomes contain H2O2
producing oxidases and catalase.
•Two important enzymes in glyoxysomes are glycolic acid oxidase and catalase.