biology f4 chapter 2

8/14/2019 Biology f4 Chapter 2

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The cell is the basic unitof life.

Biologist learned aboutcellular structure by using

light and electron

microscope.

INTRODUCTION


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ANIMAL CELL

PLANT CELL
http://www.rkm.com.au/CELL/Plant/plant-cell.htmlhttp://www.rkm.com.au/CELL/animalcell.html


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NUCLEUS

CELL MEMBRANE GOLGI APPARATUS

ENDOPLASMARETICULUM

MITOCHONDRIA

LYSOSOMES
http://www.rkm.com.au/CELL/animalcell.html


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VACUOLE

CHLOROPLAST
http://www.rkm.com.au/CELL/Plant/plant-cell.html


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PLASMA MEMBRANE


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Also known as the cell membrane

A thin membrane around the cytoplasm of

a cellA selective permeable or semi-permeable

Is made up of two lipid layers

Separates a cell from its externalenvironment

Holds the cell content together

Controls the exchange of moleculesbetween the cell and its externalenvironment


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CELL WALL


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Is a rigid cellulose layer surroundingthe plasma membrane of plant cells

Permeable to all fluids because it hastiny pores that allow substance tomove freely into and out of the cell

Provides support and protection forthe cell

Protects the plant cell from rupturing

due to the excessive intake of water


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CYTOPLASM

Refers to region between the nucleus andplasma membrane

A continuous aqueous solution containingorganelles (except nucleus), salts, dissolved

gases, nutrients, enzymes and other organicmolecules

Gives shapes to the cell

Provides a medium for all cellular biochemicalreactions

Provides substance obtained from theexternal environment to the organelles


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NUCLEUS

Nuclearmembrane


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An organelle bounded by the nuclear

membrane (two layers), containing anucleolus, chromosomes, and

nucleoplasm

Controls all the cells activitiesSeparate the genetic material

(chromosomes) from the cytoplasm

Chromosomes carry genetic in its DNA(deoxyribonucleic acid)


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VACUOLE


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A small cavity in the cytoplasm of a cell,

bound a single and semi permeable

membrane (tonoplast)

The fluid contained in the vacuole called cell

sap

Its contains water, organic acids, sugars,

amino acids, mineral salts, waste substances,

pigments and metabolic by product

Generally for storage, digestion and waste

removal

Central vacuole in plant cell for storage and

cell expansion

Food vacuoles in amoebafor phagocytosis


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MITHOCHONDRIA


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A small spherical or cylindrical-shaped

organelles

Has two membranes; an inner

membrane and an outer membrane

Forms the cells powerhouse

Produces adenosine triphosphate

(ATP), which is an energy source for the

cell


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ENDOPLASMIC RETICULUM


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Connected to the nuclear membrane

Exists as Rough Endoplasmic Reticulum

(Rough ER) and Smooth EndoplasmicReticulum (Smooth Endoplasmic Reticulum)

Rough ER has ribosomes attached to its

surfaceSmooth ER does not have ribosomes attach

to its surface

Rough ER synthesises and transportsproteins made by ribosomes

Smooth ER synthesises and transports lipids


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RIBOSOMESAre compact spherical organelles found in

large numbers in all cells

Are either attached to the ER or occur

freely in the cytoplasm

Consists of two sub-units, one small and

one large

Are small protein factories for protein

synthesis

Use information carried by the

chromosomes to make these proteins


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GOLGI APPARATUS

The Golgi complex isdistribution and shipping

of cell's chemical

products.

It modifies proteinsand fats built in

endoplasmic reticulum andprepares them for exportto outside of cell.


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LYSOSOMES


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Membrane-bound sacs that contain digestive

enzymes (hydrolytic enzymes)

Digest or break down complex organicmolecules such as proteins, lipids,

polysaccharides and nucleic acids

Also eliminate worn out mitochondria andother damaged organelles to enable a cell to

renew itself

Lysosomes also digest bacteria by breakingdown the bacteria cell wall


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CENTRIOLES


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Are paired cylindrical organelles just outside

the nucleus

Lie at right angles to each otherEach centriole consists of nine tubes, each

tubes with three tubules

Are found only in animal cellsInvolved in cell division (mitosis and

meiosis)

Migrate to opposite poles of the cell (duringcell division)

Produce spindle to assist the movements of

chromosomes


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CHLOROPLAST


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Lensshaped organelles

Have an inner and outer membrane

Contain the green pigment (chlorophyll) in

the granum/ grana

Chlorophyll traps sunlight and converts

light energy into chemical energy during

photosynthesis


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A cell can be thought as a factory, with differentdepartment each performing specialized task


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SIMILARITIES BETWEEN ANIMAL CELLS ANDPLANT CELLS

ANIMAL CELL PLANT CELL

Both has;nucleus, cytoplasm,

mithochondrion, ribosome, cell

membrane, endoplasmic reticulumand golgi apparatus

DIFFERENCES BETWEEN ANIMAL CELLS AND


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DIFFERENCES BETWEEN ANIMAL CELLS ANDPLANT CELLS

ANIMAL CELL FEATURE PLANT CELL

Generally smaller SIZE Generally larger

Do not have fixedshape

SHAPE Fixed and regularshaped

Absent CELL WALL Thick, hardcellulose

Usually notpresent

VACUOLE Present

Absent CHLOROPLAST present

Present CENTRIOLE Absent

Glycogen FOOD STORAGE Starch

THE DENSITY OF ORGANELLES IN


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THE DENSITY OF ORGANELLES INSPECIFIC CELLS

The density of an organelle refers to thetotal number of that particular organelle

within the cell

Some cells have high densities of certainorganelles

Each organelles in a cell carries out a

specific functionLike organelles, cells are specialised in their

respective functions


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For a cell to perform its specialised function

well, it needs high densities of certainorganelles to coordinate and carry out that

specialised function

For example, cells that are specialised inproducing enzymesgenerally have more

endoplasmic reticulumand ribosomes to

synthesise proteins, and manymitochondriato supply enough energyfor

its activities

Types of cell Functions Organelles found


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Types of cell Functions Organelles found

abundantly or which occur

in high density

Sperm cells Require energy to propel

through the uterus towards the

Fallopian tubes, so that

fertilsation can take place

MitochondriaMuscle cell,

for example flight

muscle cells ininsects and birds

Contract and relax to enable

movement and flight

Meristematic cell Require large amount of energy

during active cell division to

produce new cells

Palisade mesophyll

cells

Absorb sunlight during

photosynthesis

Chloroplast

Pancreatic cells Synthesis and secrete


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Pancreatic cells Synthesis and secrete

enzymes and hormones

Rough endoplasmic

reticulum and golgi

apparatus

Cells in the salivaryglands Synthesise and secreteenzymes

Intestinal and stomach

epithelium

Secrete digestive enzymes

Liver cells Carbohydrate metabolism and

detoxification of drugs and

poisons

Smooth endoplasmic

reticulum

Cells in the root cap Secrete a slimy lubricant that

helps the movement of roots

between soils particles

Golgi apparatus


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CELLORGANISATION


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LIVING PROCESS INUNICELLULAR ORGANISMS

Unicellular organisms are single-cellorganisms capable of carrying out thefollowing basic life processes:

FeedingReproductionRespiration

ExcretionLocomotionSensitivity

Grow


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Amoeba sp


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General features

Free-living in freshwater environments aswell as in soil water

Has irregular shape

Its plasma membrane encloses the

cytoplasm; the outer layer (ectoplasm)and

the inner layer (endoplasm)Other cellular structures are a nucleus,

food vacuoles and a contractile vacuoles


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LOCOMOTION

It moves by flowing its cytoplasm forward,forming a pseudopodium that helps it to

move forward slowlyA pseudopodium means a false foot

This is also known as the amoeboidmovement

FEEDING


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FEEDINGIs an holozoic and eats algae, bacteria, plant

cells and other microscopic organismIt feeds by engulfing tiny food particleswith its pseudopodia, forming a bubble-likefood vacuole to contain the foodThe food vacuoles fuses with the lysosomeand the food is digested by a hydrolyticenzyme called lysozyme.

The resulting nutrient are absorbed into thecytoplasmIndigestible material is expelled

This is called phagocytosis


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OSMOREGULATION

Water continually moves into the amoebaby osmosis

To prevent the organism from bursting,

the contractile vacuole collects all theexcess water

When the vacuoles is full, it expel thewater outside the cell

The exchange of gases, nutrients andwaste substance occur through the plasmamembrane by diffusion


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REPRODUCTION

An amoeba sp reproduces asexually by;binary fission and formation of spores

Binary fission takes place (in favourableconditions and sufficient food supply) bymitotic division of a single parent cell

Formation of spores;

Its takes place when the conditions are dryand there is insufficient food


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CELL SPECIALIZATION IN MULTICELLULAR


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CELL SPECIALIZATION IN MULTICELLULARORGANISMS

TISSUES

CELLS

ORGANS

SYSTEMS

ORGANISM


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CELL ORGANISATION INANIMALS


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CELLS

Are the basic units of structure andfunction in living organisms

May serve a specific function within theorganism

Examples :

Red blood cells transport oxygen

Nerve cells transmit nerve impulses

TISSUE


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TISSUE

Made up of cells which are similar instructure and function and all are workingtogether to perform a specific activity

Can be classified into four main types;Epithelial tissue

Muscle tissue

Connective tissueNerve tissue

EPITHELIAL TISSUE


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EPITHELIAL TISSUE

It is made up of cells closely packedandranged in one or more layers.Epithelial tissue covers the whole surfaceof the body(skin and mouth area) andinner linings of cavities (digestive tractand lung)Some undergo changes to form exocrine

and endocrine glandsFunction ; protective barrier againstinfections, mechanical injuries anddehydration (skin)


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Simple squamous epithelium

Epithelial tissue at the lining of lungs, body

cavities, heart and blood vessels


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Stratified epithelium

Epithelial tissue at the surface of the skin and

lining of the mouth and esophagus


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Simple cuboidal epithelium

Epithelial tissue at the lining kidney tubules,

glands and ducts


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Simple columnar epithelium

Epithelial at the lining of the small intestine


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Ciliated columnar epithelium

Epithelial tissue at the lining of the trachea

M l ti


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Muscle tissue

Muscles can be divided into three maingroups according to their structure, e.g.:Are the basic units of structure andfunction in living organisms

Smooth muscle tissue (intestine, blood

vessels, urinary, reproductive tract)

Skeletal muscle tissue (arms and legs)

Cardiac muscle tissue (walls of the

heart)

Nerve tissue


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Nerve tissue


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Composed of neurons or nerve cells

Each neurons consists of cell body andnerve fibres called dendritesand axons

Specialised to detect stimuli and

transmit electric signals called nerveimpulse to muscles or glands

Nerve tissues control and coordinate

activity of the body


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Connective tissue

Consists of various types of cell andfibers separated by an extracellularmatrix

Loose connective tissue (bindsepithelia to underlying tissue andholds organ in place)

Dense fibrous connective tissue (canbe found in tendons and ligaments)


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Cartilage


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Cartilage

A strong and flexible connective tissue

The skeletons of sharks and humanembryos are composed of cartilage.

Provides flexible support for certain

structures in adult humans including thenose, trachea and ears.

AdiposeA form of loose connective tissue that

stores fat.

Bl d


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Blood

Produced in the bone marrow, located at

the end of long bonesHas regulating, transporting and protectivefunctions

Bone

Consists of cells embedded in a matrix ofcollagen which are hardened by mineraldeposits such as calcium.

Provides protection to organ and supportbody

TISSUE


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Epithelial

tissue

Muscle

tissue

Nerve

tissue

Connective

tissue

Stratifiedepithelium

Simple cuboidal

epithelium

Simple columnar

epithelium

Ciliated columnar

epithelium

Simple squamous

epithelium Smooth muscle

tissue

Skeletal muscle

tissue

Cardiac muscle

tissue

Bones

Blood

Adiposetissue

Cartilage

Dense fibrous

connective tissue

Loose connective

tissue


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ORGANS

Made up of two or more types of tissuesthat work together to perform a particularfunction

Some organs perform than one functionExamples:

The heart pumps blood around in the

bodyThe stomach digests food

The kidney get rid of waste substances

and control the amount of water in body

SKIN


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SKIN

SYSTEM


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SYSTEMAre group of two organs or more that work together to

perform a specific function for the organism

NERVOUS

SYSTEM

DIGESTIVE

SYSTEM

SKELETAL

SYSTEM

CELL ORGANISATION IN


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CELL ORGANISATION INPLANT

PLANT TISSUE


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PLANT TISSUE

MERISTEMIC

TISSUE

PERMANENT

TISSUE

EPIDERMAL

TISSUE

GROUND

TISSUE

VASCULAR

TISSUE

PHLOEMXYLEM

SCHELRENCHYMA

TISSUE

COLLENCHYMA

TISSUE

PARENCHYMA

TISSUE


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ORGANS AND SYSTEMS IN


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ORGANS AND SYSTEMS INPLANTS

Leaf, stem, root and flower are someexample of organs in plant

Flowering plant consists of two mainsystem;

Root system (all the root of the plant)

Shoot system (stems, leaves, buds,flowers and fruits)

REGULATING THE INTERNAL


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REGULATING THE INTERNALENVIRONMENT

Internal environmentthe interstitial

fluid and blood plasma

Interstitial fluid- fills the space between

the cells and constantly bathes the cellsExchanges the nutrients and wastesubstance with the blood plasma contained

in blood capillaries

FACTORS AFFECTING THE


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FACTORS AFFECTING THEINTERNAL ENVIRONMENT

Physical factors

Temperature

Blood pressure

Osmotic pressure

Chemical factors

SaltSugar content

PH value


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HOMEOSTASIS

The maintenance of a relatively constantinternal environment for the cells to functionoptimally

In a homeostatic control, there must be amechanism thats consists of a;

Stimulus which is a change in the internalenvironment

Receptor to detect the stimulus

Corrective mechanism to bring about anegative feedback

BLOOD SUGAR LEVEL


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BLOOD SUGAR LEVEL

Normal

Sugar Level

Normal

Sugar Level

Blood sugar

level falls

Pancreas secretes

insulin

Blood sugar

level rises

Blood sugar

level falls

Blood sugar

level rises

Pancreas secretes

glucagon

MERISTEMATIC TISSUES


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MERISTEMATIC TISSUES

Consists of small cell which havethin walls, large nuclei, dense

cytoplasm and no vacuolesYoung actively dividing cells whichhave not undergo differentiation

Located at the tips of roots andbuds of shoots

PERMENANT TISSUE


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PERMENANT TISSUE

Mature tissue that have

undergone differentiation or arestill undergoing differentiation

EPIDERMAL TISSUE


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EPIDERMAL TISSUEThe outermost layer

Covers the stems, leaves and root ofyoung plants

Most epidermal cells are flat and have

large vacuolesCuticle is a cell which are exposed to theair which are covered with a waxy

waterproof coatingMinimises water loss, protects frommechanical injury and prevents invasion of

diseases

PARENCHYMA TISSUE


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Least specialised

Found in all the organs of a plant

Thin primary walls and largevacuoles

Store sugar and starch

Give support and shaped toherbaceous plants (turgid)

PARENCHYMA TISSUE

COLLENCHYMA TISSUE


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COLLENCHYMA TISSUE

Have unevenly thickness cell wall

Support non-woody (herbaceous) plant,young stems and petioles

SCLERENCHYMA TISSUE


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SCLERENCHYMA TISSUE

Have cell walls which areuniformly thickened by lignin andmay be dead

Give support and mechanicalstrength to mature regions of a

plant

XYLEM


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XYLEM

Consists mainly of xylem vesselsjoined together end to end (fromthe roots right up to the leaves)

Transport water and dissolvedmineral salts from the roots to

another parts of the plant

PHLOEM


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PHLOEM

Consists of sieve tubes which arearranged end to end to form longcontinuous tube-like structure

Transport organic compound (newsynthesised carbohydrates and aminoacids) from leaves to other part of

plants


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biology f4 chapter 2

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