Cells & Tissues Flashcards
what is magnification?
increase in apparent size of an object when seen under microscope.
what is resolution?
minimum distance between two point on an object that can be distinguished as two separate entities.
what is a microscope?
a device used for the magnification of the sample
who developed first compound microscope?
Zacharias Janssen 1595
resolution of human eye is ______.
0.1mm
with the help of ______, resolution can be increased.
lenses
types of microscope?
2 LM EM
LM’s magnification power?
1500X
LM’s resolving power?
0.2 micrometer
what is micrograph?
a photograph taken through a microscope.
what is LM
A light microscope works by passing visible light through a specimen. It uses two glass lenses i.e. eyepiece & objective.
EM’s magnification power?
upto 1,000,000X
EM’s resolving power?
0.2nm
what is EM?
what is TEM?
specimens are cut into extremely thin sections before studying
TEM is used to study the internal cell structure
why EM can’t be used to study life processes?
vacuum chamber
what is SEM?
what did Aristotle contributed to the formation of cell theory?
he presented the idea that all animals and plants are somehow related.
who described cells at first?
British scientist Robert Hooke in 1665.
who saw living cells for the first time?
Dutch naturalist Antonie van
Leeuwenhoek. He observed tiny organisms (from pond water) under his microscope and called
them as “animalcules”.
who discovered the first nucleus?
British botanist Robert Brown
1831
what did Matthias Schleiden contribute to the cell theory?
He stated that all plants are aggregates of individual cells which are fully independent.
who was Theodor Schwann?
1839, a German zoologist
he reported that all animal tissues are also composed of individual cells.
who was Rudolf Virchow?
1855, a German physician, proposed an important extension of cell theory. He proposed that all living cells arise from pre-existing cells (“Omnis cellula e celula”).
who was Louis Pasteur?
In 1862, Louis Pasteur provided experimental proof that microorganisms i.e. bacteria could be be produced from existing bacteria.
what does modern cell theory state?
- All organisms are composed of one or more cells.
- A cell is the structural and functional unit of organisms.
- Cells arise only by divisions in previously existing cells.
who first proposed cell theory?
Schleiden and Schwann proposed cell theory in its initial form.
how many types of eukaryotic cells are there?
2
animal cell & plant cell
what are organelles?
small, subcellular bodies with specific structure and function present within the cytoplasm of a cell.
only eukaryotes have cell membranes. false/true
false
All prokaryotic and eukaryotic cells have a thin and elastic cell membrane covering the cytoplasm.
types of proteins in plasma membrane?
3
integral
peripheral
glycoproteins
How does the cell membrane contribute to maintaining the internal composition of a cell?
The cell membrane is selectively permeable, which means it allows only specific molecules to enter or exit the cell.
cholesterol in cell membrane is used for ______________.
retaining the fluidity, it is present between the phospholipids.
what is cell membrane structure represented by?
fluid mosaic model
what substance are allowed to enter & leave plasma membrane?
oxygen food and water
waste products
where are proteins present in membrane?
protein molecules are embedded in lipid bilayer.
chemically, cell membrane is mainly composed of _______________.
proteins and lipids with
small quantities of carbohydrates.
functions of cell membrane?
structural support
selective permeability
cellular communication
explain fluid mosaic model?
According to this model, there is a lipid bilayer in which the protein molecules are
embedded.
The lipid bilayer gives fluidity and elasticity to membrane. Small amounts of carbohydrates are also found in cell membrane. In eukaryotic cells cholesterol is also present in lipid bilayer.
components of plasma membrane?
Phospholipids
cholesterol
proteins
small quantity of carbs
cell membrane is _________ permeable.
selectively
how many and what are the fundamental types of biomolecules?
plcn
Painted Lilies Create Nature
all of ‘em are macromolecules
carbohydrates, lipids, nucleic acids, and proteins.
what is the fluid inside the nucleus called?
nucleoplasm
why is nucleus in plant cell shifted to side?
due to the formation of large central vacuole.
Nuclear envelope contains many small pores that enable it to act as a ______________.
semi-permeable membrane.
nucleoli
singular: nucleolus
staining region in nucleus is called ____________.
nucleolus/nucleoli (plural)
treated with a stain or dye to enhance the visibility of certain structures.
function of nucleolus
ribosomal RNA are formed and assembled as ribosomes.
in which phase chromatin condenses to form chromosome?
prophase
chromosomes are composed of _________.
DNA & proteins
what is a nucleus?
Eukaryotic cells have a nucleus, which is a double-membraned organelle that contains the cell’s DNA.
The nucleus is located in the center of animal cells, but it may be pushed to the side in plant cells due to the large central vacuole.
The nuclear envelope is the double membrane that surrounds the nucleus. It contains many pores that allow molecules to pass between the nucleus and the cytoplasm.
The nucleoplasm is the fluid inside the nucleus. It contains nucleoli, chromosomes, and other proteins.
Nucleoli are dark spots in the nucleoplasm that are the site of ribosome production.
Chromosomes are thread-like structures made of DNA and proteins. They are only visible during cell division.
Prokaryotic cells do not have a nucleus. Their DNA is in the cytoplasm in the form of a single chromosome.
how does a prokaryotic cell look like?
don’t contain prominent nucleus. Their chromosome is made of DNA only
and is submerged in cytoplasm.
__________ controls all activities of a cell.
nucleus
what is the difference between cell membrane and nuclear envelope?
The nuclear envelope is a double membrane that surrounds the nucleus. It is made up of two lipid bilayers.
The cell membrane is a single membrane that surrounds the entire cell. It is made up of a lipid bilayer
what is a cytoplasm?
the semi-viscous and semi-transparent substance between plasma membrane and nuclear envelope.
name a biochemical reaction that happens in the cytoplasm?
Glycolysis (breakdown of glucose during cellular respiration).
why does cytoplasm contain water?
It contains water in which many organic molecules (proteins,
carbohydrates, lipids) and inorganic salts are completely or partially dissolved.
Cytoplasm provides ______ for the proper functioning of ________ and also acts as the site for various ______________.
space
organelles
biochemical (metabolic) reactions.
ribosomes are found in both prokaryotic and eukaryotic cell. T/F
True
Eukaryotic ribosomes are slightly smaller/larger than prokaryotic ones.
larger
in what forms ribosomes are found?
2
1. attached with ER
2. freely dispersed in cytoplasm
what are ribosomes?
are ribosomes bounded by a membrane?
no
what are ribosomes made of?
equal amounts of rRNA & proteins
Ribosomes are the sites of _______________.
protein synthesis
what is ER?
a network of interconnected channels that extends from cell membrane to nuclear envelope.
function of RER?
protein synthesis
function of SER?
important role in lipid formation
Detoxification of drugs in the liver
it forms vesicles to transport large molecules from one part of a cell to the other.
which one has no ribosomes attached with it? SER or RER?
SER
that’s why it’s called smooth.
who discovered the Golgi complex?
Italian physician Camillo Golgi
what is lumen?
inner open spaces of the cisternae in Golgi apparatus.
what is Golgi apparatus?
series of flattened sacs formed of membranes. It modifies molecules coming
from rough ER and packs them into small membrane bound sacs called Golgi vesicles. These sacs can be transported to various locations in cell or to its exterior, in the form of secretions.
Vesicles are seen at the ________ of the _______of Golgi complex.
stack (cisternae)
edges
explain the process when molecule go from RER into Golgi complex?
The vesicles containing molecules bud off from the ER and carry their cargo to the Golgi apparatus.
explain the process when molecules enter the Golgi complex?
The molecules enter the Golgi apparatus after being transported from the rough ER. As the molecules move through the Golgi cisternae, they undergo modifications, such as having sugars added to them or having other molecules attached. These modifications are essential for the molecules to become fully functional.
explain the process when the molecule is done being modified and ready for departure. (from Golgi complex)
Once the molecules are modified and sorted within the Golgi complex, they are packaged into vesicles. These vesicles bud off from the edges of the Golgi cisternae, containing the modified molecules.
explain the process when the vesicle is transported to its destination.
These vesicles transport the molecules to different destinations within or outside the cell, depending on their type and function. Some vesicles may carry molecules to lysosomes, which are organelles responsible for digesting waste and cellular debris. Some Golgi vesicles, known as secretory vesicles, move towards the cell membrane in the form of secretions.
what are lysosomes?
Lysosomes are small, spherical organelles enclosed by a single lipid bilayer membrane. Lysosomes contain various active hydrolytic enzymes which breakdown molecules.
why is a membrane important in lysosome?
prevents the enzymes and other molecules within the lysosome from leaking into the rest of the cell.
is mitochondria double or single membrane bounded structure?
double membrane bounded
mitochondria is only found in eukaryotes. T/F
True
The outer membrane of a mitochondrion is _________ but the inner membrane forms many __________,
called _______, singular (______)
smooth
infoldings
cristae
crista
why are infoldings in mitochondria important?
to increase the surface area of inner membrane on which membrane-bound reactions can take place, so more ATP will be released.
The ribosomes of mitochondria are more similar
to ______________ than to ________________.
bacterial ribosomes
eukaryotic ribosomes
what is matrix and function of it?
mitochondrial solution where all necessary enzymes are for the production of ATP.
what is mitochondria?
Mitochondria are spherical, elongated tiny, double membrane-bounded structures found only in eukaryotes.
These are the sites of aerobic respiration, and are the major energy production centers.
Mitochondria have their own _________________.
ATP full form?
DNA and ribosomes.
Adenosine Triphosphate
what is the function of centrioles?
to help in the formation of spindle fibers during cell division.
In some cells, centrioles are involved in the formation of cilia and flagella.
The two centrioles
are collectively called a ____________.
centrosome
what are centrioles
Animals and many unicellular organisms have hollow and cylindrical organelles known as
centrioles. Each centriole is made of nine triplets of microtubules (made up of tubulin protein).
how are centrioles placed by Allah?
the two centrioles are usually placed at a right angle to each other
what is a cytoskeleton?
a supportive network of microfilaments and microtubules. It’s responsible for cell shape and movement.
what are the three main kinds of fibers?
Microfilaments, the thinnest
Microtubules, the thickest
Intermediate Filaments, between thickness
Microtubules are made of __________ and are used by cells to ______________. They are also the major component of _______________.
tubulin protein
hold their shape
cilia and
flagella.
Microfilaments are _______and are made of ________.
thinnest
actin protein
cilia looks like _______
flagellum looks like ________
hair
whip like structure.
structure of cilium & flagellum?
it consist of nine pairs of microtubules that surround a single central pair of microtubule.
cilium & flagellum are connected to the ___________.
what is it?
basal body
it serves to anchor a cilium & flagellum to the cell.
anchor: moor (make fast (a boat) by attaching it by cable or rope to the shore or to an anchor) a ship to the sea bottom with an anchor.
anchor: basal body
ship: cilia
what is protoplasm?
it refers to the entire living substance found within a cell, which includes both the cytoplasm and the nucleus.
what is cellulose?
Cellulose is a complex carbohydrate (polysaccharide) composed of glucose molecules linked together. It forms the main structural component of plant cell walls.
Cellulose provides rigidity and strength to the cell wall, contributing to the overall structural support of the cell and the plant.
how many layers of cell wall are there?
3
middle lamella
primary wall
secondary wall
middle lamella?
middle lamella is present between adjacent primary walls of the two cells. It is formed of sticky gel like substance (pectin).
adjacent: neighbouring, next door
pectin: complex carbohydrate that serves as a glue-like substance, helping to cement plant cells together.
function of cell wall?
4
It provides shape, strength, protection and support to the inner living matter (protoplasm) of cell.
primary wall?
is a true wall and develops in newly growing cell. It consists of cellulose and other compounds.
primary cell wall is only found in plants.
secondary wall?
is formed between the primary cell wall and the plasma membrane. It is much thicker
It is formed in woody tissues examples: stem and nuts
It has lignin and cellulose.
secondary wall has ____________.
lignin and cellulose
plasmodesmata?
There are pores in the cell walls of adjacent cells, through which
their cytoplasm is connected. These pores are called plasmodesmata.
what are the minute pores in cell wall called?
plasmodesmata
function of plasmodesmata?
forms living connection between the cells.
chitin is present in the cell wall of _______.
fungi
Prokaryotes have a cell wall composed of __________ that is a complex of ___________________.
peptidoglycan
amino acids and sugars.
bacteria
protein breaks down into ___________ by ________ which is a type of _______________ which is itself a type of ________.
amino acids
proteases
hydrolytic enzyme
protein
function of vacuole?
storage of nutrients, water and waste products
what is a vacuole?
sac-like structure bounded by a single membrane. Mature plant cell have a large central vacuole.
when does a cell becomes turgid?
Cells have many small vacuoles in their cytoplasm. However, when a plant cells matures its small vacuoles absorb water and fuse to form a single large vacuole in center.
Cell in this state becomes turgid.
what are plastids?
Plastids are membrane-bound organelles that only occur in the cells of plants and photosynthetic protists (algae). They are 3 types
chloroplasts, leucoplasts and chromoplasts.
chromoplasts function?
help plants in pollination and dispersal of fruits
leucoplasts function?
store starch, proteins and lipids.
leucoplasts are ___________ in color and store _____________.
colorless
starch, proteins and lipids.
chromoplasts are _____________ in color and are present in __________ and its function is _____________.
pigments associated with
bright colors
in the cells of flower petals and fruits.
to help in pollination and dispersal of fruit.
chloroplasts is bounded by single/double membrane. The outer membrane is ________ & the inner membrane ________. The stack of thylakoids is called ____________.
double
smooth
gives rise to sacs called thylakoids.
granum (plural = grana).
The stack of thylakoids is
called ___________.
granum
Grana which is ________________ float in the inner fluid of __________ called ________.
the stack of thylakoids
chloroplast
stroma
the inner part of granum is called __________.
lumen
where are the pigment in chloroplast present?
chlorophyll (the green pigment necessary for photosynthesis).
It present in the thylakoids of grana.
what is the outermost layer in the leaf called?
epidermis
it is a SINGLE layer of CELLS.
a waxy substance called ______________ which forms the ____________ covers the ________________.
cutin
cuticle
upper epidermis
cutin is in the cuticle and cuticle is the outermost covering of plants.
function of epidermis?
protect the tissues and to prevent loss of water.
what are stomata?
Stomata are tiny openings or pores in plant tissue typically present in the lower epidermis that allow for gas exchange.
what is the function of chloroplasts?
The primary function of chloroplasts is to conduct photosynthesis, a process in which they capture light energy and convert it into chemical energy (glucose) while releasing oxygen as a byproduct.
why guard cells contain chloroplasts?
the presence of chloroplasts in guard cells allows them to undergo photosynthesis, influencing the osmotic pressure within the cells and, consequently, regulating the opening and closing of stomata for efficient gas exchange and water balance in plants.
function of guard cells?
control opening and closing of stoma.
Gas exchange regulation.
Control of water loss.
Photosynthesis support.
Environmental response.
Protection.
function of stomata?
exchange of oxygen and carbon dioxide and evaporation of water vapor takes place through stomata.
what is mesophyll? types?
between the two epidermal layers lies the group of cells called mesophyll.
2
palisade
spongy
the palisade mesophyll consists of ________________?
2 or 3 layers of cylindrical cells.
the spongy mesophyll
the word mesophyll is derived from?
from Greek work Mesos meaning middle
phyllo meaning leaf
as it is present in the middle of leaf.
spongy mesophyll consists of _____________?
loosely arranged irregular cells having chloroplasts.
where are intercellular spaces present in the cells? why?
intercellular?
spongy mesophyll
diffusion of gases
the space between cells
xylem and phloem vessels?
xylem vessels are present in the leaves and are long and dead that transport water from roots to leaves.
phloem cells carry the prepared food from the leaf to other parts of the plants.
which cells contain many chloroplasts?
palisade mesophyll cells
cylindrical cells
explain root hair cells?
the extensions of the epidermal cells. The root hair is long and narrow & provides large S.A for the absorption of water & mineral salts from the soil.
explain xylem vessels?
explain RBCs.
enucleated (more space for haemoglobin)
disk-shaped
slightly biconcave (large S.A for gas diffusion at faster rate)
RBCs are ____________ in shape because?
slightly biconcave
larger surface area for diffusion of gases in & out of the cells at a faster rate.
what is an open system?
separated from its surroundings by a boundary that allows transfer of materials and energy across it.
explain cell as an open system?
what is nucleoid?
Prokaryotes chromosome consists of DNA only and it floats in cytoplasm near center. This region is called nucleoid.
the ________ of ___________ is composed of ________________ called peptidoglycan.
cell wall
prokaryotes
complex material
name things that are common in prokaryotes and eukaryotes?
cell wall
plasma membrane
ribosomes
DNA
cytoplasm
diff b/w prokaryotes and eukaryotes?
in fungi cell wall is made of?
chitin
SA:V is small?
If the surface area to volume ratio is small, the cell is very big.
what is facilitated diffusion? example?
When a transport protein moves a substance from higher to lower concentration, the
process is called facilitated diffusion. Only particular molecules can pass through them. The rate of facilitated diffusion is higher than simple diffusion.
transport of glucose into the cell.
which diffusion occurs faster facilitated diffusion or diffusion? why?
facilitated diffusion
what is tonicity?
it refers to the relative concentration of solutes in the solutions being compared.
OR
the capability of a solution to modify the volume of cells by altering their water content.
define osmosis?
the movement of water molecules from a region of high water concentration to a region of low water concentration across a partially permeable membrane.
define isotonic hypotonic and hypertonic solution?
(i) Hypertonic solution: A solution having a higher concentration of solute as compared to another solution is called hypertonic solution . In a hypertonic solution, a cell progressively loses water through exosmosis.
(ii) Hypotonic solutions: A solution having a lesser concentration of solute as compared to another solution is called hypotonic solution . In a hypotonic solution, a cell progressively gains water through endosmosis.
(iii) Isotonic solutions: A solution having a concentration equal to that of another solution is called isotonic solution. In an isotonic solution, a cell neither gains nor loses water.
what is exosmosis, plasmolysis and endosmosis?
Exosmosis: net movement of water molecules out of a cell when the cell is placed in hypertonic solution.
Endosmosis: net movement of water molecules into the cell when the cell is placed in hypotonic solution.
Plasmolysis: When cell is placed in a hypertonic solution water moves out, first from cytoplasm and then from vacuole. The shrinking of cytoplasm is called plasmolysis.
Plasmolysis occurs in plant cells only and not in animal cells.
what is turgor pressure?
the swelling of a plant cell in hypotonic solution creates turgor pressure.
hypertonic solutions have _______ solute concentrations outside the cell and ___________ solute concentrations inside the cell.
higher
lower
more water inside so it looses and shrinks.
hypotonic solutions have _______ solute concentrations outside the cell and ___________ solute concentrations inside the cell.
lower (outside)
higher (inside)
less water inside so it gains water and swells. hypo : less stuff, more water (outside the cell)
large organisms have __________ surface area-to-volume ratio.
less
less A:V means less surface area and more volume.
microorganisms have __________ surface area-to-volume ratio.
more
more A:V means more surface area and less volume. so that they can carry out diffusion and transport
cz they don’t have specialized systems
more and less S.A:A means what?
high S.A:V means more surface area compared to its volume. (small cells)
less S.A:V means less surface area compared to its volume. (large cells)
FMIGTN
the surface area to volume ratio gets _________ as the cells get larger
smaller
larger cells have less S.A so less S.A:V.
what is active transport?
Active transport is the movement of molecules from an area of lower concentration to an area of higher concentration. This movement against the concentration gradient requires energy in the form of ATP.
True or false? Active transport can only take place across a membrane.
true
explain sodium-potassium pump?
the membranes of nerve cells have carrier proteins in the form of “sodium-potassium pump”. In resting (not conducting nerve impulse) nerve cell, this pump spends energy (ATP) to maintain higher concentrations of K+ and lower concentrations of Na+ inside the cell. For this purpose, the pump actively moves Na+ to the outside of the cell where
they are already in higher concentration.
Similarly this pumps moves K+ from outside to inside the cell where they are in higher concentration.
define endocytosis? and its types?
It is the process of cellular ingestion of bulky materials by the infolding of cell membrane
2 types
phagocytosis
pinocytosis
phagocytosis (cellular eating) and pinocytosis (cellular drinking).
In phagocytosis cell takes in solid material while in pinocytosis cell takes in liquid in the form of
droplets.
examples phagocytosis: amoeba engulfs paramecium
wbcs bacteria
pinocytosis: cell lining in small intestine absorption of fat droplets.
define exocytosis?
It is the process through which bulky material is discharged by packaging it in secretory vesicles and moving vesicles to the cell surface.
The membrane of the vesicle fuses with the cell membrane and the contents are expelled out.
This process adds new membrane which replaces the part of cell membrane lost during endocytosis.
what are tissues?
a group of cells with similar shape and function.
Each type of tissues is specialized to perform a particular biological function.
how many types of animal tissues are there?
epithelial, connective, muscular, and nervous.
types of epithelial tissue?
5
structure and function of squamous epithelium?
the cells are thin and flattened & arranged as a single layer.
passage of material by diffusion & filtration.
structure and function of columnar epithelium & ciliated & stratified?
long & narrow.
secretion, absorption & protection.
long & narrow (columnar in shape)
have cilia
transports material through tubes & passage ways.
Like squamous.
protection
present in esophagus and skin.
where are squamous epithelium & columnar epithelium mostly present?
It (squamous) is found in lungs, heart and blood vessels.
It lines stomach and intestine.
alimentary canal, gall bladder.
where are ciliated & cuboidal tissues present?
It is present in trachea and bronchi. lining of respiratory passages and propels mucous.
It (cuboidal tissues) is found in tubules of kidneys,
and duct of glands.
is cartilage fibrous or hard tissue? which type?
hard
connective
why?
It’s firm and rigid but not as hard as bone. It provides structural support & flexibility in various parts of the body, such as in the joints & nose and ears.
provides cushioning and support between bones at joints.
which are flexible?
bone
tendon
cartilage
ligaments
cartilage
ligaments
name hard, fluid & fibrous tissues? function?
hard: bone and cartilage
fibrous: tendons and ligaments
support body and movement
maintain skeletal structure.
fluid: blood transports substances in the body.
what is matrix?
the connective tissue cells are widely separated by matrix which is found between the cells and consists of non-cellular material that varies from solid to semisolid to fluid. They have fibers.
tendons connect _________ to __________.
___________ connect __________ to ____________.
muscles
bones
ligaments
bones
bones
what is adipose tissue and function?
fatty connective tissue
found b/w skin & internal organs
insulation, stores energy & protection of internal organs.
name types of connective tissue?
6
adipose
cartilage
bone
blood
tendons
ligament
what are cartilage cells and matrix called?
Chondroblasts
chondrin
what is the most abundant tissue in an animal?
Muscle Tissue
muscle fibers contain __________.
what is its function?
actin filaments
myosin filaments
cause the movement of the body & body parts.
what are the other names for
1st type of muscular tissue?
voluntary (hand and legs)
skeletal (attached to bones)
striated (has striations)
what is skeletal muscle tissue? what is it a type of?
aka striated muscles are attached to bones by tendons. Their cells are striated & are multinucleated. They are responsible for the voluntary movements of bones.
type of muscular tissue. (animal tissue)
what is smooth muscle tissue?
page 60
where is smooth muscle tissue found?
in the walls intestine, stomach, urinary bladder, blood vessels
etc.
which type of tissue is present in the iris of the eyes?
Smooth muscle
intercalated discs are found in which muscle?
Cardiac muscle
what is the identifying feature of skeletal muscle, smooth & cardiac?
multinucleated
lacks striations
intercalated disc
FMIGTN
multinucleated: more than 1 nucleus.
what is cardiac muscle?
Cardiac muscles are present in the wall of heart. Their cells are also striated but there is a single nucleus in each cell. They produce heartbeat.
where is the function of nervous tissue & where is it present?
Nervous tissue forms a communication system.
This tissue is mainly composed of neurons, which are specialized to conduct messages in the form of nerve impulses.
Nervous tissue is found in brain, spinal cord and nerves.
what is & where is meristematic tissue present?
a type of simple tissue
dividing power
the cells are thin walled
have large nucleus
small or no vacuoles.
have no intercellular spaces
found at the apex of root, shoot & girth.
what are lateral meristems?
Lateral meristems are located on the lateral sides of roots and shoot.
By dividing, they are
responsible for increase in girth of plant parts. This growth is called secondary growth.
They are further of two types i.e. vascular cambium (located between xylem and phloem) and cork cambium (in the outer lateral sides of plant).
cambium=girth
what are apical meristems?
Apical meristems are located at the apices of roots and shoot.
When they divide they cause increase in the length of plant. Such growth is called primary growth.
what is permanent tissue? types of permanent tissue?
Permanent tissues originate from meristematic tissue. The cells of these tissues do not have the ability to divide.
3 types
what is epidermal tissue?
if a plant has epidermis and it has no intercellular spaces then how does gaseous exchange occur?
stomata
structure of epidermal tissue?
what type of tissue is it? take a hint from its function & structure
just think about what structure it need to have for its function.
single layer
living (cells)
thick walled (cells)
no intercellular space
flat cells
have pores called stomata.
it’s a type of simple permanent tissue. plant tissue
example the modification of epidermal tissue?
root epidermal cell grow hair like extension, which increases surface area.
the function of the epidermis? (in plants)
In roots, they are responsible for the absorption of water and minerals.
On stem and leaves, they secrete cutin (the coating of cutin is called cuticle) which prevents evaporation & parasitic infections.
explain epidermal tissue?
what is the most abundant types of cell in plants?
parenchyma cells
what is ground tissue?
Ground tissues are simple tissues made up of parenchyma cells.
Overall they are spherical but flat at point of contact. They have thin primary cell walls and have large vacuoles for storage of food. No secondary walls.
In leaves, they are called mesophyll and are the sites of photosynthesis. In other parts, they are the sites of respiration and protein synthesis.
where are collenchyma cells found?
Collenchyma tissue is found immediately (cortex) under the epidermis, young stems, petioles, and leaf veins.
what plant cells do & do not have secondary cell wall?
DO:
DON’T:
collenchyma
parenchyma cells
function of collenchyma tissue?
They are flexible & provide support in parts of the plant that are still growing.
which have dead cells
collenchyma, sclerenchyma parenchyma?
dead:
sclerenchyma
living:
collenchyma
parenchyma
is sclerenchyma thick cell walled? why? are they living or dead? why? types of sclerenchyma tissue?
thick secondary wall due to deposition of lignin.
to provide hardness & rigidity.
dead
because the have thick cell walls leaving narrowness in the cell.
fibre & sclereid (stone cell)
difference b/w fibre and sclereid?
page 62
FMIGTN
why do sclerenchyma cells have thickened secondary cell walls?
where are sclerenchyma cells found? sclerenchyma tissues are subdivision of what type?
deposition of lignin
usually found in non-growing regions of plant bodies, such as the bark or mature stems.
supporting tissue
permanent tissue
simple tissue
plant tissue
how many types of compound tissues are there? compound tissues are subdivision of what type?
2
xylem
phloem
Plant tissues
function of complex tissues?
xylem: conduction of water & dissolved mineral salts.
provide strength & support.
phloem:
Why does the presence of __________ in the ___________ of its cells make xylem tissue a significant contributor to providing ___________ to the plant body?
Due to the presence of lignin, the secondary walls of its cells are thick and rigid. That is why xylem tissue also provides support to plant body.
xylem cell types?
phloem cell types?
2
tracheids:
vessel elements or cells: it has thick secondary cell walls. They
lack end walls and join together to form long tubes.
2
sieve tube: formed by end-to-end fusion of cells.
companion cells: it makes proteins for sieve tube cells.
they’re attached to sieve tube elements.
They regulate or control the movement of food through sieve tubes.
what is the only living cell of xylem tissue? what is its function?
parenchyma cells
responsible for photosynthesis storage of food
they even have no secondary walls unlike other cells that have thick secondary walls.
what are sieve plates?
sieve tube elements (cells) have porous end walls.
porous: having minute holes through which liquid or air may pass.
