Have you noticed how workers at aconstruction site lay bricks to build thewalls of a house ?Just as the walls of a house are madeof bricks, livings organisms are madeof basic units called cells. They form the building blocks of allliving organism.
• Generally cell can be divided to two types, plant cell and animal cell.• Both animal and plants cells consist of cytoplasm,nucleus and surrounded by a thin layer of plasma membrane.
WHAT IS ORGANELLE?The cytoplasm contains structurescalled organelles.Organelles perform specific functionswhich enables the cell to function as aunit of life.Besides the nucleus, other examples oforganelles include mitochondria,chloroplast, vacuoles, ribosomes,lysosomes and the Golgi apparatus.
Refers to all the membranes found inside the cell• the membrane at the surface which encloses the content of a cell is called plasma membrane.• made of proteins and phospholipids• separates the content of a cell from the outer environment.• semi-permeable and regulates the movement of substances into and out of the cytoplasm.
• Rigid outer layer that surrounds the plasma membrane of plant cells• composed of cellulose,a a tough and fibrous carbohydrate• permeable to all fluids• gives shape to a plant cell• provides mechanical support• protection from rupturing
• region between the nucleus and the plasma membrane.• jelly-like matrix in which organelles are suspended.• acts a a medium for biochemical reactionsin the cell.• provides substances obtained from the external environment to the organelles.
• large,dense and spherical organelle enclosed by nuclear membrane• contain nucleolus, chromatin @ chromosome and nucleoplasm• choromosomes carry genetic information• controls all the activities which take place in the cell
• fluid-filled sac surrounded by tonoplast• contain cell sap• plant cell contain more vacuole compared with animal cell• helps to regulate water balance• acts as a storage place in a cell• support herbaceous plant
• compact spherical organelles found attached to the surface of the rough endoplasmic reticulum or suspended freely in the cytoplasm• contains two subunits,comprises a type of ribonucleic acid (RNA) and protein• synthesis protein
• physically continuos with the nuclear membrane• two types: rough ER and smooth ER• RER: transport protiens made by ribosome• SER: the site of important metabolic reactions,including synthesis of lipids
golgi apparatus• functions as a processing, packaging and transporting centre of carbohydrates, proteins, phospholipids and glycoproteins
lysosomes• membrane-bound sacs that contain hydrolytic enzymes• eliminate worn out mitochondria and others damaged organelles• digest bacteria by breaking down the bacteria cell wall
QUESTION 3Which of the following is true about the cell gives shape to a plant cell provides mechanical support protection from rupturing• A – cell wall• B – cell membrane• C – cytoplasma• D - vacoule
QUESTION 5 Which of the following is the function of chloroplast A - gives shape to a plant cell• B - contain green pigment chlorophyll• C - store energy in the form of ATP• D - provides mechanical support