Plant Tissues and Growth PDF

ALIA NAZIRA – ↘ A plant consists of two types of tissues, meristematic tissues and permanent tissues ↘ Meristematic tissues are actively dividing tissues through mitosis PERMANENT TISSUES » Permanent tissues are matured tissues which have experienced or ar...

ALIA NAZIRA – ↘ A plant consists of two types of tissues, meristematic tissues and permanent tissues ↘ Meristematic tissues are actively dividing tissues through mitosis PERMANENT TISSUES » Permanent tissues are matured tissues which have experienced or are experiencing differentiation » There are three types of permanent tissues 1. Epidermal tissues 2. Ground tissues 3. Vascular tissues 1 | CHAPTER 1 – ORGANISATION OF PLANT TISSUES AND GROWTH ALIA NAZIRA → Involved in the repair and regeneration of plant tissue as well as in the vascular system COLLENCHYMA TISSUES Epidermal tissues ❑ Collenchyma tissues are made of living cells which mature into cells ∆ Epidermal tissues layer the that are flexible outermost surface of stems, leaves ❑ Have cell walls made of pectin and and roots of young plants hemicellulose ∆ Epidermal cell walls which are ❑ Their cell walls are thicker than the exposed to the air have a waxy and parenchyma tissues waterproof layer called cuticle ❑ Provide mechanical support and ∆ The cuticle reduces loss of water elasticity to plants through evaporation (transpiration), protects the leaf from mechanical SCLERENCHYMA TISSUES injuries and pathogens » Sclerenchyma tissues consist of dead ∆ There are modified epidermal cells cells when they are matured according to their functions: » Their cell walls are the thickest I. Guard cells – control the among the three ground tissues opening of the stoma » Provide support and mechanical II. Root hair cells – increase the strength to the parts of matured surface area of the root for plants water and mineral salts » These tissues also help in the absorption transport of water and nutrients in plants Ground tissues PARENCHYMA TISSUES Vascular tissues XYLEM → Parenchyma tissues are simplest living cells and do not undergo ◊ Xylem is made up of dead cells differentiation without the cytoplasm → They have the thinnest cell walls ◊ The cell wall of xylem contains lignin → Parenchyma tissues are always in a ◊ Consists of xylem vessels that are turgid state providing support and elongated, hollow and connected to maintaining the shape of herbaceous each other from its roots to the plants leaves → Involved in photosynthesis, help in ◊ This enables xylem to transport the storage od starch and sugar, and water and mineral salt to all parts of involved in gaseous exchange a plant 2 | CHAPTER 1 – ORGANISATION OF PLANT TISSUES AND GROWTH ALIA NAZIRA PHLOEM ribosome as they decompose at maturity stage  Phloems are made of companion cells  Phloems consist of sieve tubes and sieve tubes arranged from end to end forming  Made of living cells, which is the elongated and continuous tube sieve tubes with the presence of structures cytoplasm  Phloems transport sugars produced  The sieve tubes do not have any from the photosynthesis from the organelles such as nucleus and leaves to storage organs such as roots, fruits and tubers 3 | CHAPTER 1 – ORGANISATION OF PLANT TISSUES AND GROWTH ALIA NAZIRA – APICAL MERISTEM TISSUE ❑ Located at the tips of plant shoots and roots LATERAL MERISTEM TISSUE ↘ Consists of vascular cambium and cork cambium ZONE OF CELL DIVISION The zone of cell division takes place at the apical meristems which consists actively dividing meristem cells through mitosis The increase of the number of cells There are three types of zones of cell causes the elongation of the plant growth stem ◊ Zone of cell division When new cells are forming, the cells ◊ Zone of cell elongation formed previously are pushed to the ◊ Zone of cell differentiation zone of elongation 4 | CHAPTER 1 – ORGANISATION OF PLANT TISSUES AND GROWTH ALIA NAZIRA » Cells differentiate to form permanent tissues such as epidermis, cortex, xylem and phloem » The cells change their shapes and structures to become specialised cells with specific functions ZONE OF CELL ELONGATION » For example, epidermal cells in leaves differentiate and form guard cells ꚛ The zone of cell elongation consists that control the opening of stoma of cells that are increasing in size » Other than that, epidermal cells in ꚛ The increase in size happens through roots differentiate and form root water diffusion by osmosis and the hair cells absorption of nutrients into the cells and stored in the vacuoles ꚛ Small vacuoles fuse to form a large vacuole (vacuolation) There are two types of growth ꚛ The diffused water exerts pressure ○ Primary growth against the cell wall which pushes, ○ Secondary growth elongates and widens the cells Primary growth ❖ Primary growth is the growth that occurs after germination and it takes place in all plants to elongate their stems and roots ❖ This growth takes place in the apical meristems at the shoot tips and root tips ❖ Primary growth starts when the meristem cells in the zone of cell division of apical meristems are actively dividing ❖ This is followed by elongation and differentiation of the cells ZONE OF CELL DIFFERENTIATION ❖ At the shoot tips, leaf primordia and shoot primordia will grow to form » The zone of cell differentiation new leaves and shoots consists of differentiating cells that ❖ This enables the plants to increase in differentiate once they have reached height their maximum size 5 | CHAPTER 1 – ORGANISATION OF PLANT TISSUES AND GROWTH ALIA NAZIRA ❖ At the root tips, the root cap will ⌂ Cork cambium become exhausted when they 1) Located under the epidermal penetrate the soil layer ❖ This causes the cells of the root cap to be replaced by the meristem cells SECONDARY GROWTH AT THE STEM 1 Secondary growth starts when the vascular cambium divides actively through mitosis Secondary growth 2 ⌂ Secondary growth occurs mainly in → The cells in the cambium ring divide eudicots and a small number of inwards to form new xylem and monocots (shrub) to increase the outwards to form new phloem circumference or diameter of plant → The new xylem tissue become stem and root secondary xylem and the new phloem tissue become secondary phloem ⌂ For non-woody plants (herbaceous plant), secondary growth does not happen ⌂ Secondary growth results from the division of lateral meristem cells located in the stem and root ⌂ Lateral meristems consist of 3 vascular cambium and cork cambium ∆ When undergoing secondary growth, ⌂ Vascular cambium primary xylem is pushed towards the i) Located between phloem and pith whereas primary phloem is xylem tissues in vascular pushed towards the epidermis bundle 6 | CHAPTER 1 – ORGANISATION OF PLANT TISSUES AND GROWTH ALIA NAZIRA ∆ As a result, the primary xylem tissues the circumference of the stem which are compressed to form a stronger causes the epidermis of the stem to wood layer stretch and crack ∆ This is because the walls of xylem ✓ Cork cambium actively divides to are thickened with lignin form cork cells on the outer side and ∆ The thickening of lignin provides cortex on the inner side mechanical support to plants ✓ The cork layer protects the stem from insect and pathogen attack when the epidermis is cracked 4 ✓ When the secondary xylem layer is compressed, there is an addiction to SECONDARY GROWTH AT THE ROOT ▪ Vascular cambium cells divide actively and combine to form a complete ring ▪ The cells in the cambium ring divide inwards to form secondary xylem and outwards to form secondary phloem ▪ Due to the vascular cambium activity, the root becomes thicker ▪ The cork cambium located under the epidermis divides actively to form cork cells ▪ The cork cells provide protection to the root tissues 7 | CHAPTER 1 – ORGANISATION OF PLANT TISSUES AND GROWTH ALIA NAZIRA SECONDARY GROWTH OF MONOCOTS ❑ Even though most monocots do not undergo secondary growth, some do ❑ For example, a) Draceana sp. b) Aloe sp. c) Agave sp. Draceana sp. Aloe sp. Agave sp. THE NECCESITY OF SECONDARY GROWTH  Provides stability to plants by increasing the stem and root diameters to suit the height of plants  Provides mechanical support to THE NECESSITY OF PRIMARY GROWTH plants Allow maximum elongation of plants  Produces more xylem and phloem to absorb sunlight for tissues photosynthesis  Produces xylem and phloem tissues Primary phloem can transport the continuously to replace old and products of photosynthesis from the damaged xylem and phloem tissues leaves to other parts of the plants  Produces stronger and thicker bark Primary xylem can transport water to provide protection to the plants and mineral salts from the soil via from excessive water loss, physical the roots to the leaves injuries and pathogen infections Primary xylem provides support to  Able to live longer by increasing the herbaceous or young plants chances of seed production and reproduction 8 | CHAPTER 1 – ORGANISATION OF PLANT TISSUES AND GROWTH ALIA NAZIRA SIMILARITIES SIMILARITIES ꚛ Both growths can increase the size of the plants permanently ꚛ Both growths occur in woody plants ꚛ Both growths involve cell division by mitosis DIFFERENCES PRIMARY GROWTH ASPECT SECONDARY GROWTH Apical meristem Meristem tissue involved Lateral meristem (vascular cambium and cork cambium) Occurs on stems and roots in Parts of the plant that Occurs when primary growth younger regions of the plant undergo growth has ceased on matured stems and roots Growth occurs longitudinally Direction of growth Growth occurs radially Increases the length of stems Growth effects Increases the thickness or and roots of plant circumference of stems and roots of plant Epidermis, cortex and primary Tissues and structures Bark, periderm (cork cambium vascular tissue (primary formed and cork tissues), lenticels xylem and primary phloem) and secondary vascular tissue (secondary xylem and secondary phloem) Do not have woody tissue Presence of woody tissue Have woody tissue Thin Thickness of bark Thick Absence of annual growth Presence of annual growth Presence of annual growth rings rings rings at the plant stem 9 | CHAPTER 1 – ORGANISATION OF PLANT TISSUES AND GROWTH ALIA NAZIRA » The presence of annual rings makes furniture look attractive and they can be made as decorative items » The woods and barks of some plants can produce resin and oil » For example, Hopea sp. (merawan) and meranti » The substances can be commercialised » Plants that undergo secondary as varnish, adhesive substance, growth have high economic values perfume and medicine because they can produce timber » Flowering plants can be made as » For example, decorative plants i. Shorea sp. (meranti) » Commercialised fruits are products ii. Balanocarpus sp. (cengal) of plants that have undergone » Plants that undergo secondary secondary growth and they are able growth have strong and hard woods to generate income as well as boost which are suitable to be used as economic growth structure as houseboats, furniture, fences, doors and others 10 | CHAPTER 1 – ORGANISATION OF PLANT TISSUES AND GROWTH ALIA NAZIRA – ꚛ After going through vegetative growth, these plants briefly stop the growth process during winter ꚛ During spring and summer, the growth Plants can be classified based on their life continues as preparation for cycle reproduction by flowering ꚛ The plants produce fruits and seeds  Annual and eventually the plants will die  Biennial ꚛ For examples  Perennial a. Cabbage ANNUAL PLANTS b. Carrot c. Silver cock’s comb » Annual plants are plants that have d. Celery only one life cycle for a season or a e. Onions year » These plants usually die after PERENNIAL PLANTS completing their biological cycle ◊ Perennial plants refer to plants which starts from germination and which live more than two years ends with flowering or producing ◊ These plants have longer lifespan seeds depending on the species and » For examples conditions 1. Paddy ◊ Perennial plants can be classified 2. Pumpkin into two categories 3. Watermelon i) Woody perennial plants 4. Corn ii) Herbaceous perennial plants 5. Pea ◊ Most of these plants are able to BIENNIAL PLANTS flower and bear fruits many times throughout their lives ꚛ Biennial plants refer to plants which ◊ These plants have structures that take two years with two seasons of are adaptable to their surroundings growth to complete their life cycle and temperature change ꚛ The first growth season is the ◊ Examples of woody perennial plants vegetative growth which is the I. Mango growth of roots, leaves and stem II. Apple structures III. Maple ꚛ The second growth season is IV. Pear reproduction V. Strawberry ꚛ Most of the biennial plants grow in ◊ Examples of herbaceous plants temperate regions i. Fennel ii. Mint 11 | CHAPTER 1 – ORGANISATION OF PLANT TISSUES AND GROWTH ALIA NAZIRA iii. Rosemary THE GROWTH CURVE OF BIENNIAL PLANTS iv. Sage → The growth curve has two sigmoid v. Thyme curves which are combined → First growth season: - Plants produce leaves, ○ The growth curve of most organisms photosynthesis takes place are sigmoid curves - Food is stored in tubers → Second growth season: THE GROWTH CURVE OF ANNUAL PLANTS - The food stored is used to ⌂ The growth curve is a sigmoid curve produce flowers and seeds ⌂ Stage A: Decreasing dry mass - Food stored in the cotyledon is used for germination before the leaves emerge to carry out photosynthesis ⌂ Stage B: Increasing dry mass - The rate of photosynthesis increases rapidly THE GROWTH CURVE OF PERENNIAL - This is because the plant has PLANTS carried out photosynthesis ❑ The growth curve is a series of small ⌂ Stage C: Constant dry mass sigmoid curves - The rate of growth is zero ❑ Every year, the growth curve is a - Plant is matured sigmoid curve ⌂ Stage D: Decreasing dry mass ❑ Growth occurs throughout the Happens slowly because of lifespan of the plant - Aging ❑ The rate of growth is high during - Lower rate of photosynthesis spring and summer - Shedding of leaves and flowers ❑ High light intensity increases the - Seed dispersal rate of photosynthesis ❑ The rate of growth decreases in winter 12 | CHAPTER 1 – ORGANISATION OF PLANT TISSUES AND GROWTH ALIA NAZIRA 13 | CHAPTER 1 – ORGANISATION OF PLANT TISSUES AND GROWTH ALIA NAZIRA – CENTRIOLE » Characteristics ∆ Small cylindrical components that exist in pairs ∆ Made up of complex arrangement of microtubules Animal Cells ∆ Does not exist in plant cells » Functions MITOCHONDRION Forms spindle fibre during cell division Plural → mitochondria Characteristics ▪ Rod-shaped or spherical ▪ Consists of two layers of membranes ꚛ Smooth outer membrane ꚛ Folded inner membrane GOLGI APPARATUS ▪ Contains enzymes that play a role in a cellular respiration ❖ Characteristics Functions Consists of a stack of ↘ As a site that generates parallel flattened sacs that energy through the glucose are coated by a single cell oxidation process during membrane cellular respiration New membrane is added at one ↘ Energy released in the form of end of the Golgi apparatus ATP (adenosine triphosphate) and vesicles bud off from the molecules other end ❖ Functions Processes, modifies, packs and transports chemicals such as ◊ Protein ◊ Carbohydrate ◊ Glycoprotein (carbohydrate and protein) 1 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA LYSOSOME ◊ Characteristics ꚛ Small spherical sac enclosed in a single membrane ꚛ Contains hydrolytic enzymes ◊ Functions → Hydrolyses complex organic molecules such as ✓ Protein PLASMA MEMBRANE ✓ Nucleic acid ✓ Lipid ⌂ Characteristics → Breaks down bacteria and ✓ Outer membrane that components of damaged cells surrounds the entire content of cell ✓ Made of proteins and phospholipids ✓ Thin and elastic film ✓ Partially permeable ⌂ Functions ↘ Separates content of cell from the external environment or extracellular NUCLEUS ↘ Controls movement of ❑ Plural → nuclei substances into and out of ❑ Characteristics the cell ❖ Largest component ↘ Allows exchange of nutrients, ❖ Spherical, compressed and respiratory gases and waste enclosed in a nuclear materials membrane with many pores ❖ The nucleus contains nucleolus, nucleoplasm and chromatin that consist of chromosomes ❑ Functions ⌂ Controls all cell activities ⌂ Has chromosomes that contain DNA (deoxyribonucleic acid) ⌂ DNA determines the cell characteristics and metabolic function 2 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA 2 Endoplasmic reticulum membrane is continuous with nuclear membrane 3 Two types of endoplasmic reticulum ❑ Rough endoplasmic reticulum that has ribosomes attached on it RIBOSOME ❑ Smooth endoplasmic reticulum (no ▪ Characteristics ribosomes) Small, compact and spherical ✓ Functions granules Consists of protein and RNA  As the transport system (ribonucleic acid) within the cell Ribosomes are present on the  Provides a wide surface for surface of the rough enzyme attachment and endoplasmic reticulum or biochemical reactions freely in the cytoplasm  The rough endoplasmic ▪ Functions reticulum transports proteins ∆ As a site for protein synthesis synthesised by ribosomes  The smooth endoplasmic reticulum ꚛ Synthesises and transports glycerol and lipids ꚛ Carries out detoxification of drugs and metabolic by- products ENDOPLASMIC RETICULUM (ER) ✓ Characteristics 1 Consists of a system of interconnected folded flattened sacs 3 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA Plant Cells CHLOROPLAST 1) Characteristics VACOULE ❑ Oval shaped ❑ Consists of two layers of ꚛ Characteristics membrane ❑ Liquid-filled sac, which is the ❑ Contains chlorophyll in the cell sap grana that give plants a green ❑ Surrounded by tonoplast colour membrane ❑ Does not exist in animal cells ❑ Young plants have many small 2) Functions vacuoles ◊ Chlorophyll absorbs sunlight ❑ Mature plants have a large and converts it to chemical vacuole energy during photosynthesis ❑ If vacuole present in animal cells, it is small ❑ Cell sap contains 1 Water 2 Organic acids 3 Sugars 4 Amino acids 5 Enzymes 6 Mineral salts 7 Oxygen 8 Carbon dioxide 9 Metabolic by-products ꚛ Functions ∆ Water is absorbed into the CYTOPLASM vacuole and becomes turgid Characteristics ∆ In unicellular animals, the ❖ Consists of jelly-like medium vacuole contracts during that contains components of 1. Osmoregulation the suspended cells 2. Osmosis ❖ Contains 3. Excretion 1. Organic compounds (protein, lipid and carbohydrate) 2. Inorganic compounds (potassium ions) Functions ▪ Acts as a medium for biochemical reactions in cells 4 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA SIMILARITIES ❑ Both cells are made of A Nucleus B Cytoplasm C Plasma membrane CELL WALL D Golgi apparatus ↘ Characteristics E Mitochondrion ∆ A strong and rigid outer layer F Endoplasmic reticulum ∆ Made from cellulose fibre G Ribosomes ∆ Fully permeable ↘ Functions I. Maintains the shape DIFFERENCES II. Provides mechanical support  Plant Cells 1 Fixed shape 2 Has a cell wall 3 Has a large vacuole 4 Stores carbohydrate in the form of starch 5 Does not have a centriole  Animal Cells a Not a fixed shape b Does not have a cell wall c Does not have chloroplasts d No vacuole or if present, it is small e Stores carbohydrate in the form of glycogen f Has centrioles 5 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA 6 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA – particles by the enzyme lysozyme in the lysosome ③ The nutrients are absorbed into the cytoplasm ∆ Unicellular organisms are made of ④ Undigested food is discharged when only one cell the Amoeba sp. moves → Amoeba sp. GROWTH → Paramecium sp. ∆ Unicellular organisms carry out ▪ Amoeba sp. grow by synthesising new I Movement cytoplasm II Nutrition RESPONDING TO STIMULI III Growth ꚛ Amoeba sp. respond to stimuli such as IV Responding to stimuli chemicals, touch or bright light by V Respiration moving away from the stimuli VI Excretion VII Reproduction RESPIRATION Amoeba sp. ∆ Exchange of oxygen and carbon dioxide gases occur through the plasma membrane by simple diffusion MOVEMENT on the surface of the cell Amoeba sp. constantly changes its EXCRETION shape when it encounters obstacles Moves by extending out its ❑ Waste is removed by diffusion such pseudopodium (false feet) as This is followed by the flow of ◊ Carbon dioxide cytoplasm into the extended ◊ Ammonia pseudopodium ❑ As Amoeba sp. live in freshwater environments, water will diffuse by NUTRITION osmosis and fill the contractile ① Amoeba sp. moves towards food by vacuole extending its pseudopodium to trap ❑ When the vacuole expands to the food particles by phagocytosis maximum size, contraction occurs and ② The food vacuole is combined with water is excreted from time to time lysosome and hydrolysed the food ❑ This process is called osmoregulation 7 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA REPRODUCTION When there is a food, Amoeba sp. will Paramecium sp. reproduce via asexual reproduction MOVEMENT that is binary fission through mitosis ꚛ Moves using rhythmic cilia beats Amoeba sp. forms spores that will only germinate when the environment NUTRITION improves if the conditions are not 1 The presence of cilium (plural: cilia) suitable such as beat helps transfer food particles I Dry conditions into the oral groove II Low temperature 2 The food vacuole is combined with III Food shortage lysosome and hydrolysed the food particles by the enzyme lysozyme in the lysosome 3 The nutrients are absorbed into the cytoplasm 4 Undigested food in the Paramecium sp. is discharged through the anus GROWTH » Paramecium sp. grow by synthesising new cytoplasm RESPONDING TO STIMULI ↘ Paramecium sp. respond to stimuli such as chemicals, touch or bright light by moving away from the stimuli RESPIRATION ▪ Exchange of oxygen and carbon dioxide gases occur through the plasma membrane by simple diffusion on the surface of the cell EXCRETION a Waste is removed by diffusion such ac → Carbon dioxide → Ammonia b As Paramecium sp. live in freshwater environments, water will diffuse by 8 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA osmosis and fill the contractile vacuole c When the vacuole expands to the maximum size, contraction occurs and water is excreted from time to time d This process is called osmoregulation REPRODUCTION 1) When there is a food, Paramecium sp. will reproduce via asexual reproduction that is binary fission through mitosis 2) When the condition is not suitable, sexual reproduction that is conjugation occurs 9 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA – MUSCLE CELL ◊ Arranged as multinuclear striated fibres NERVE CELL ◊ Contract and relax to generate movement ⌂ Long and thin in shape ⌂ Functions in sending nerve impulses WHITE BLOOD CELL EPITHELIAL CELL ✓ Can change shape ❖ Thin and flat cells ✓ Functions in destroying pathogens ❖ Coats the surface of organs SPERM CELL RED BLOOD CELL Has long tail to enable it to swim ❑ Does not contain a nucleus towards the ovum in the Fallopian ❑ Shaped as a biconcave disc tube ❑ Functions to optimise transportation The head carries a set of of oxygen chromosomes from the male 10 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA PALISADE MESOPYHLL CELL  Consists of long cylindrical cells, arranged vertically and close to each other  Contains high chlorophyll density  This arrangement allows maximum absorption of sunlight for photosynthesis SPONGY MESOPHYLL CELL SIEVE TUBE ELEMENT ꚛ Cells are loosely arranged with lots 1. Long cylindrical arranged from end of air space in between to end ꚛ Large air space allows exchange of 2. Transports organic materials from gas from the inside of the leaves to leaves to storage organs such as the palisade mesophyll cells fruits GUARD CELL XYLEM VESSEL » Modified lower epidermal cells with the thicker cell wall on the inner side ∆ Long, continuous hollow tube » Controls the opening and closing of ∆ Functions in transporting water and the stoma mineral salts from the root to the » Stoma is the opening that allows the other parts of the plant exchange of oxygen and carbon dioxide 11 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA ROOT HAIR CELL d) Epithelial tissues that coat the trachea have projections like hair Has a long projection which adds known as cilia surface area for the absorption of e) Types of epithelial tissues water and mineral salts ① Epithelial tissue that covers the surface of the mouth and oesophagus ② Epithelial tissue that covers the surface of lungs, body → Tissues are a group of cells that have the same structure and function ③ Epithelial tissue that covers and are arranged together to carry the surface of the trachea an out a specific function bronchus → Four different types of tissue A) Epithelial tissue B) Muscle tissue C) Nerve tissue D) Connective tissue ④ Epithelial tissue that lines tubules, glands and kidney Epithelial Tissue ducts a) Epithelial tissue covers the outer surface (skin) and hollow surfaces in the body b) For example ⑤ Epithelial tissue that covers ▪ Digestive tract the small intestine ▪ Respiratory tract c) The epithelial tissue on the skin protects against ⌂ Infections ⌂ Injuries ⌂ Chemicals ⌂ Dehydration 12 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA Muscle Tissue Nerve Tissue There are three types of muscle tissue ❑ Made of neuron or nerve cells ❑ Each neuron consists of a cell body 1. Smooth muscle and nerve fibre 2. Skeletal muscle ❑ Nerve fibre are called dendrite and 3. Cardiac muscle axon SMOOTH MUSCLE ❑ Can detect stimuli and then send information in the form of an ◊ Contraction and relaxation of electrical signal (nerve impulses) to smooth muscle enable involuntary the muscles and glands activities ❑ Regulates and controls body activity ◊ For example: peristalsis along the digestive tract SKELETAL MUSCLE Connective Tissue ↘ Involved in controlled movement 1) Loose connective tissue ↘ Contract and relax to generate 2) Fibrous connective tissue movement in bones and limbs 3) Blood tissue 4) Bone 5) Adipose tissue 6) Cartilage LOOSE CONNECTIVE TISSUE ꚛ Links the epithelial tissue to the CARDIAC MUSCLE tissue below it ▪ Builds walls of the heart that ꚛ Fixes the organs in their positions contract to pump blood to the whole body ▪ The contraction is involuntary 13 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA FIBROUS CONNECTIVE TISSUE ADIPOSE TISSUE ⌂ Form tendons and ligaments  Connective tissues keep fat under ⌂ The tendon connects bones and the skin dermis and the surface of all muscles main organs ⌂ The ligaments connect bones to bones BLOOD TISSUE CARTILAGE » Plays a functional role in regulation, Encloses bone tips to prevent the transportation and protection bone from wearing out Cartilage BONE ∆ Bone forms the body frame ∆ Protects the internal organs 14 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA Ground Tissue Three types of ground tissue 1 Parenchyma tissue 2 Collenchyma tissue 3 Sclerenchyma tissue PARENCHYMA TISSUE → Functions to store I Starch II Protein III Water → Can also carry out photosynthesis SCLERENCHYMA TISSUE » Functions in providing support and mechanical strength to all mature parts of the plant COLLENCHYMA TISSUE Functions in giving support to A) Young plants B) Non-woody plants (herbaceous plants) 15 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA Vascular Tissue PHLOEM TISSUE ❖ Functions in transporting organic - Made up of matters such as sucrose from the a Xylem tissue leaves to all parts of the plant b Phloem tissue XYLEM TISSUE Functions in transporting water and mineral salts from the roots to the other parts of the plant Ligneous xylem tissue wall provides support and mechanical strength to the plants FAILURE OF MITOCHONDRION COMPONENTS Failure of mitochondrion or mitochondrion disjunction can cause stunted growth, weak muscles, FAILURE OF LYSOSOME COMPONENTS hearing and vision problems Tay-Sachs is a hereditary disease caused by the failure of enzymes to produce in the lysosome Tay-Sachs patient will experience stunted growth and mental retardation 16 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA Types of cells Cell component found in Function abundance Sperm cell Requires energy to swim to fertilise the secondary oocytes Muscle cell (flight muscle cells mitochondrion Requires energy to contract in insects and birds) and relax to enable flight Plant meristem cell Requires a lot of energy to carry out active cell division Palisade mesophyll cell Absorbs more sunlight to chloroplast carry out the process of Spongy mesophyll cell photosynthesis Pancreatic cell Increases synthesis and Rough endoplasmic reticulum secretion of digestive enzymes Goblet cell in intestinal Golgi apparatus Produces mucus epithelium and respiratory tract Liver cell Smooth endoplasmic Metabolises carbohydrate and reticulum detoxification of drugs and poisons 17 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA – ✓ A group of different tissues combine to form organs ✓ Organs perform special functions as a result of the combination of tissues that form the organ ✓ For example, the heart organ is composed of ꚛ Epithelial tissue fills up the space in the heart RESPIRATORY SYSTEM ꚛ Cardiac muscle tissue ▪ Characteristics functions in pumping blood to - Trachea the rest of the body - Nose ꚛ Connective tissues connect - Lungs the systems in the organ - Diaphragm ꚛ Nerve tissue regulates the ▪ Function rhythm of the heartbeat - Exchange of oxygen and ENDOCRINE SYSTEM carbon dioxide gases between the body and external ∆ Characteristic environment ❑ The endocrine gland that secretes hormones ∆ Function ❑ Coordinates body activities with the nervous system MUSCULAR SYSTEM ↘ Characteristics ◊ Skeletal muscles ◊ Smooth muscles 18 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA ◊ Cardiac muscles ↘ Function FEMALE REPRODUCTIVE SYSTEM ◊ Contracts and relaxes to produce movements in ⌂ Characteristics different parts of the body ❖ Ovary ❖ Uterus ❖ Fallopian tube ❖ Vagina ❖ Cervix ⌂ Function ❖ Produces ovum and female sex hormones MALE REPRODUCTIVE SYSTEM Characteristics » Testes » Prostate gland LYMPATHIC SYSTEM » Penis » Characteristics Function  Spleen » Produce sperm and male sex  Lymph nodes hormone  Lymph vessels » Functions  Maintains balance of bodily fluids  Prevents infection diseases 19 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA NERVOUS SYSTEM Characteristics ꚛ Brain ꚛ Spinal cord ꚛ Peripheral nerves Functions ꚛ Detects and sends information ꚛ Coordinate body activities DIGESTIVE SYSTEM → Characteristics a) Mouth b) Oesophagus c) Stomach d) Liver e) Pancreas f) Small intestine g) Large intestine BLOOD CIRCULATORY SYSTEM → Function a) Digests food into a simpler Characteristics form for easy absorption A) Heart B) Artery C) Vein D) Blood capillary Function A) Transports nutrients, respiratory gases and waste products 20 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA URINARY SYSTEM  Characteristics Kidney Ureter Urethra Bladder  Function Eliminates waste products such as urea and uric acid from the body INTEGUMENTARY SYSTEM ❖ Characteristic Skin ❖ Function Protects the body from physical injury, infection and dehydration SKELETAL SYSTEM ꚛ Characteristics ⌂ Bone ⌂ Cartilage ⌂ Ligament ⌂ Tendon ꚛ Functions ⌂ Supports the body ⌂ Protects the internal organs ⌂ Provides a base for muscle SHOOT SYSTEM adhesion » Consists of stems, leaves, shoots, flowers and fruits » Stems and twigs are support system that support the leaves at a vertical position to allow maximum 21 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA absorption of sunlight during photosynthesis » Flowers are involved in the pollination process ROOT SYSTEM ↘ Consists of all roots in a plant ↘ Function in absorbing water and mineral salts ↘ Function in providing support for plants 22 | CHAPTER 2 – CELL BIOLOGY AND ORGANISATION ALIA NAZIRA – » *phobic = phobia (scared of / don’t like something) ∆ The heads of the phospholipid molecule in the outer layer face the extracellular fluid ∆ The phospholipid heads in the inner 1 Living cells require substances from layer face the cytoplasm the external environment to carry ∆ The tails of the phospholipid out living processes molecule of two layers face each 2 At the same time, the metabolic other processes in cells produce waste that ∆ The protein molecules embedded need to be disposed of from the cells partially or fully within the 3 Cells must allow some substances to membrane move into and out of the cells to ∆ The protein molecules are widely maintain the living processes dispersed between the phospholipid 4 The movement of substances into and bilayer out of the cell is regulated by the ∆ There are two types of protein plasma membrane molecules A) Channel proteins B) Carrier proteins ∆ Glycoprotein and glycolipid are carbohydrate chains attached on some proteins and lipids ∆ According to the fluid mosaic model, ∆ Functions of glycoprotein and protein molecules float within the glycolipid are phospholipid bilayer, forming a 1) Act as receptors to hormones mosaic pattern that changes (insulin) frequently 2) Stabilise the membrane by ∆ Each phospholipid molecule consists forming hydrogen bonds with of water » A polar head which is 3) Act as antigens for cell hydrophilic (attracted to identification water) ∆ Cholesterols that found between the » A nonpolar tail which is phospholipid molecules make the hydrophobic (repels water) phospholipid bilayer a) Stronger 1 | CHAPTER 3 – MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANE ALIA NAZIRA b) More flexible c) Less permeable to water- soluble substances (ions) ∆ The phospholipid bilayer, proteins and cholesterols are not static but I. The plasma membrane is permeable if form a dynamic and flexible structure the substances is able to pass through it freely or impermeable if the substances is unable to pass through it II. The plasma membrane is a selectively permeable membrane III. The selectively permeable membrane is permeable to water IV. The plasma membrane only allows free movement of certain molecules across it and prevent or limit the movement of the other substances V. The plasma membrane has a selectively permeable property due to its building structure VI. The phospholipid bilayer and protein determine the membrane permeability towards specific substances WHAT WILL HAPPEN IF THERE IS NO FLUID MOSAIC MODEL CHOLESTEROL? Refers to a protein molecule that ▪ Without cholesterols, the membrane are suspended in the phospholipid will become too permeable to bilayer forming an ever-changing dissolved substances mosaic pattern ▪ It also become too fluid at a normal body temperature that may cause it to rupture 2 | CHAPTER 3 – MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANE ALIA NAZIRA 3 | CHAPTER 3 – MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANE ALIA NAZIRA – 2) Small molecule and ion 3) Large molecule NONPOLAR MOLECULES ▪ Fatty acid ▪ Glycerol ▪ Fat soluble vitamins (ADEK) ▪ Steroid compounds Three common factors for a substance to SMALL MOLECULE AND ION pass through the plasma membrane ◊ Polar molecules (water) Molecule size ◊ Nonpolar molecules (oxygen, carbon Polar molecule dioxide) Ionic charge ◊ Ion (K+, Na+, Ca+, Mg+) Characteristics of movement of substances LARGE MOLECULE across a plasma membrane ▪ Glucose 1) Nonpolar molecules ▪ Amino acid 4 | CHAPTER 3 – MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANE ALIA NAZIRA Osmosis ꚛ Passive transport does not require ꚛ Osmosis is a process similar to simple energy diffusion that only involves water ꚛ Three types of passive transport molecules 1 Simple diffusion ꚛ Refers to the net movement of water 2 Osmosis molecules from an area of high water 3 Facilitated diffusion potential (low solutes concentration) to an area of low Simple Diffusion water potential (high solutes concentration) through a selectively ❖ Simple diffusion is the movement of permeable membrane molecules or ions from an area of ꚛ Does not require energy high concentration to an area of low concentration ❖ The molecules move down the concentration gradient until a dynamic equilibrium is achieved ❖ This may occur with or without the presence of a plasma membrane ❖ Does not require energy ❖ Molecules that can pass through the plasma membrane via simple diffusion A) Lipid soluble (fatty acids, glycerol) B) Oxygen C) Carbon Dioxide 5 | CHAPTER 3 – MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANE ALIA NAZIRA Facilitated Diffusion o Channels have specific internal characteristics that only allow specific ions to pass through it  Lipid-insoluble molecules (ions) and large molecules (amino acids, CARRIER PROTEINS glucose) move across the membrane ⌂ Have specific sites and can only bind with the aid of transport proteins to a specific molecule (carrier or channel protein) via ⌂ For example, glucose molecules can facilitated diffusion only bind to the specific site of a  Does not require energy because the glucose carrier protein transport proteins transport molecules down a concentration gradient until a dynamic equilibrium is achieved  The transport proteins ① Channel proteins ② Carrier proteins CHANNEL PROTEINS o Form channels or canals to allow small-sized solutes and ions to diffuse across the plasma membrane 6 | CHAPTER 3 – MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANE ALIA NAZIRA 5) Carrier proteins change shape when a phosphate group » The characteristics of movement of attaches to it substances across a plasma membrane » Active transport results in the via active transport accumulation or excretion of 1) The movement of molecule or molecules or ions ion substances are against a » Carrier proteins that involved in this concentration gradient process are known as pumps 2) Does require energy from ATP SODIUM-POTASSIUM PUMP that are generated during ▪ In animal cells, the carrier proteins cellular respiration that transport sodium ions to 3) Does require specific carrier extracellular and potassium ions into protein with specific sites the cell are called sodium-potassium 4) Carrier proteins also possess pump receptors to bind with ATP molecules 7 | CHAPTER 3 – MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANE ALIA NAZIRA PROTON PUMP ◊ Found on the epithelial cells lining SIMILARITIES the stomach cavity ❑ Moving a substance across a ◊ Causes the acidity of the stomach membrane contents ❑ Occurs through a selectively ◊ Energy from the ATP enables permeable membrane hydrogen ion to be transported by the carrier protein (proton pump) DIFFERENCES towards the extracellular fluid PASSIVE TRANSPORT ACTIVE TRANSPORT ◊ This causes accumulation of the Energy is not Requires energy hydrogen ion and acid production in required the stomach cavity Occurs following the Occurs against the concentration of concentration of the gradient the gradient Occurs until a There are dynamic equilibrium accumulation and is achieved disposal of molecules or ions 8 | CHAPTER 3 – MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANE ALIA NAZIRA – ACTIVE TRANSPORT Occurs during: ∆ Absorption of glucose and amino acids in the villus ∆ Reabsorption of glucose through the PASSIVE TRANSPORT renal tubule in the kidney ∆ Transport of sucrose form a leaf to Occurs during: a phloem tissue Gaseous exchange between an ∆ Absorption of mineral ions by a plant alveolus and a blood capillary via root hair cell simple diffusion Reabsorption of water via osmosis trough the renal tubule in the kidney Absorption of water by a plant root hair cell via osmosis Absorption of fructose molecule in the villus via facilitated diffusion 9 | CHAPTER 3 – MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANE ALIA NAZIRA HYPERTONIC SOLUTION Definition Solution A has a high solutes concentration and low water potential ISOTONIC SOLUTION Example a Solution A is hypertonic to solution Definition Solution A and B have the B same concentrations of b Water diffuses from solutions solution B to solution Example 1) Solutions A and B are A via osmosis isotonic toward each other 2) No net movement of water HYPOTONIC SOLUTION Definition Solution A has a low solutes concentration and high water potential Example a) Solution A is hypotonic to solution The Effects on Animal B b) Water diffuses from solution A to solution Cells B via osmosis EFFECT OF HYPOTONIC SOLUTION ◊ Water will diffuse into the red blood cells by osmosis, causing the cells to swell and undergo haemolysis when the cells are placed in the hypotonic solution ◊ Haemolysis is the burst of red blood cells 10 | CHAPTER 3 – MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANE ALIA NAZIRA ◊ This is because the plasma membrane is too thin to withstand the osmotic pressure built up in the cells The Effects on Plant Cells EFFECT OF HYPERTONIC SOLUTION EFFECT OF HYPOTONIC SOLUTION o Water will move out of the red blood cells by osmosis, causing the cells to ↘ Water will diffuse into the vacuoles undergo crenation when the cells are by osmosis when plant cells are placed in the hypertonic solution placed in a hypotonic solution o Crenation is the shrink of red blood ↘ This will make the vacuoles to cells expand cause it to push the cytoplasm and plasma membrane against the cell wall and becomes turgid ↘ Plant cells do not burst because the cell wall is rigid and strong ↘ Turgor pressure is important to plant cells because it gives support and maintains the shape of cell ↘ Cell turgidity causes the guard cell to swell to allow the stomata to EFFECT OF ISOTONIC SOLUTION remain open for photosynthesis ⌂ Water diffuses into and out of the red blood cells by osmosis at the same rate ⌂ No net movement of water across the plasma membrane ⌂ The cells maintain their normal shape 11 | CHAPTER 3 – MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANE ALIA NAZIRA EFFECT OF HYPERTONIC SOLUTION are placed in a hypertonic solution causing the cells to undergo Water will diffuse out of the plasmolysis vacuoles by osmosis when plant cells Plasmolysis is where vacuoles and the EFFECT OF ISOTONIC SOLUTION cytoplasm will shrink, causing the When the sap of the plant cell and plasma membrane to be pulled away extracellular solution are isotonic, from the cell wall water potential is the same Plasmolysis also causes leaves and The movement of water diffusion in stems to bend downwards and wilt and out of the cell is the same Plasmolysed plant cells can regain Cells become flaccid their turgidity by going through deplasmolysis where the cells are returned to a hypotonic solution immediately 12 | CHAPTER 3 – MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANE ALIA NAZIRA – b) Saline Solutions → Isotonic solution to the blood plasma → Contains 0.85-0.90 g sodium 1 Excessive use of fertilisers may chloride per 100 ml cause wilting in plants c) Isotonic Drinks 2 Dissolved fertilisers will cause soil → Help athletes to recover loss water to be hypertonic to the sap of water and electrolytes cell of roots (potassium, sodium) through 3 Water will diffuse by osmosis from perspiration the roots’ cell sap to the soil d) Liposomes consequently and cells will become → Vesicles that contain aqueous plasmolysed solution 4 Cells in plants will recover once they → Surrounded by a phospholipid are watered bilayer membrane 5 If the period of plasmolysis is → Used to protect drugs or prolonged, wilted plants will active substances taken orally eventually die from being destroyed by gastric juices e) Reverse Osmosis a) Rehydration Drinks (oral rehydration → A technology commonly used salts) to extract fresh water from → Help to recover loss of water sweater using the desalination and electrolytes in individuals process with diarrhoea 13 | CHAPTER 3 – MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANE ALIA NAZIRA → In a reverse osmosis equipment, pressure is applied to push the seawater through a semi-permeable membrane → The membrane allows water molecules to pass through it but not foreign particles → As a result, only pure fresh water is released 14 | CHAPTER 3 – MOVEMENT OF SUBSTANCES ACROSS THE PLASMA MEMBRANE ALIA NAZIRA – COHESIVE FORCE AND ADHESIVE FORCE OF WATER → Cohesive force refers to water molecules that are attached to each POLARITY OF WATER other ❖ Water is an inorganic compound → Adhesive force refers to water consisting of the hydrogen (H) and molecules that are attached to other oxygen (O) elements surfaces ❖ Water molecules are polar molecules → Both forces produce the capillary because shared electrons between action which allows water to enter oxygen and hydrogen will be attached and move along narrow spaces, such towards oxygen which is more as in the xylem tube electronegative (-) ❖ This polarity produces hydrogen bonds and allows water to act as a universal solvent ❖ The universal solvent properties of water allow solutes (glucose) and electrolytes to be transported through the plasma membranes into cells for biochemical reactions SPECIFIC HEAT CAPACITY OF WATER Water has a high specific heat capacity of 4.2 kJ kg-1 ○C-1 This means that 4.2 kJ of heat energy is required to raise the temperature of one kilogram of water by 1○C Water absorbs a lot of heat energy with a small rise in temperature This characteristic is very important to maintain the body temperature of organisms 1 | CHAPTER 4 – CHEMICAL COMPOSITION IN A CELL ALIA NAZIRA – ✓ Most polysaccharides are formed from this ❑ Organic compounds are chemical sugar compounds that contain carbon » Fructose elements ✓ Sugar found in honey ❑ Large and complex compounds form and sweet fruits macromolecules » Galactose ❑ Most macromolecules are polymers ✓ Sugar found in milk comprising small molecules known as ⌂ Has a reducing power, which is the monomers (building blocks) ability to transfer hydrogen (or ❑ Carbohydrates, proteins and nucleic electron) to the other compounds acids are polymer molecules of ⌂ When monosaccharide is heated in organic compounds Benedict’s solution, the monosaccharide will reduce the blue copper (II) sulphate to a brick red precipitate of copper (I) oxide There are three main types which is insoluble in water ⌂ This process known as reducing ◊ Monosaccharides (simple sugars) sugars ◊ Disaccharides ◊ Polysaccharides (complex sugars) DISACCHARIDES MONOSACCHARIDES ꚛ Formed when two simple sugar molecules (monosaccharides) combine ⌂ Carbohydrate monomers, which are through condensation to form the simplest carbohydrate units disaccharide units ⌂ Can combine to form polymers ꚛ Involves the removal of a water through a condensation reaction molecule ⌂ Most taste sweet, can form crystals and dissolve in water ⌂ Example: » Glucose ✓ Sugar found in plants (rice, wheat) and fruits (grapes) ꚛ Can be broken down to their ✓ Most commonly found monosaccharide units through monosaccharide hydrolysis 2 | CHAPTER 4 – CHEMICAL COMPOSITION IN A CELL ALIA NAZIRA ꚛ Involves the addiction of one water Insoluble in water due to their large molecule molecular size Neither taste sweet nor crystilise Can be disintegrate through hydrolysis with the help of 1. Dilute acids 2. Boiling o Example: 3. Enzyme action o Maltose 1) Found in grains 2) Reducing sugars o Lactose 1) Found in milk I. As a source of energy (glucose) 2) Reducing sugars II. As a food reserve (glycogen in animal o Sucrose cells, starch in plant cells) 1) Found in sugar cane, - Starch is the main storage of sweet fruits and sugar polysaccharide in plant cells beet - Starch also found in 2) Non-reducing sugars chloroplasts because it does not - Source: grains, potatoes, reduce copper (II) legumes sulphate solution - Glycogen is the main storage POLYSACCHARIDES of polysaccharide found in muscle cells and animal liver Sugar polymers consisting of cells monosaccharide monomers III. As a support structure (cellulose in Formed through the condensation the plant cell wall) process - Cellulose forms the main Involves hundreds of structure of the plant cell monosaccharides to form long wall molecular chains → *Chitin is a type of polysaccharide → *The advantage is that chitin will that used as a surgical thread decompose after the sewn wound heals 3 | CHAPTER 4 – CHEMICAL COMPOSITION IN A CELL ALIA NAZIRA – » Each dipeptide can be broken down into an amino acid through hydrolysis ∆ Protein is a complex compound composed of carbon, hydrogen, oxygen and nitrogen elements ∆ Most of proteins contain sulphur and phosphorus » There are 20 types of amino acids ∆ Example of protein present naturally A) Fish » Various type of polypeptide B) Meat molecules can be formed from 20 C) Milk types of amino acids D) Beans » This is because each type of protein E) Eggs differs in terms of the amino acid sequence in its polypeptide chain POLYPEPTIDES ◊ Proteins that are composed of one or more polymers known as polypeptides ◊ Each polypeptide is made up of monomers or small units known as Build new cells amino acids Repair damaged tissues ◊ A polypeptide can consist of fifty to For the synthesis of enzymes, thousands of amino acids molecules hormones, antibodies and ◊ Amino acids are linked together haemoglobin through the condensation process Form building blocks, such as 1) Keratin in the skin DIPEPTIDES 2) Collagen in bones » Dipeptides are composed of two 3) Myosin in muscle tissues amino acid molecules which are linked together by a peptide bond through ∆ The breakdown of proteins or the condensation process polypeptides by digestive enzymes » Involves the removal of water gives us the energy to carry out our molecule daily activities » Further condensation can link more ∆ Polypeptides can disintegrate into amino acids to form a polypeptide amino acids then used again to build chain the protein molecules needed by the body 4 | CHAPTER 4 – CHEMICAL COMPOSITION IN A CELL ALIA NAZIRA – glycerol molecule with three molecules of fatty acids ❑ Lipids are naturally occurring → Triglycerides can be hydrolysed again hydrophobic compounds found in into fatty acids and glycerol through plant and animal tissues the reaction of hydrolysis ❑ Lipid is made up of carbon, hydrogen → Glycerols are a type of three carbon and oxygen elements with a higher alcohol that contain three hydroxyl ratio of hydrogen to oxygen atoms groups (-OH) ❑ Lipids are insoluble in water but soluble in other organic solvents (alcohol, ether, chloroform) → There are two types of fatty acids There are four types I Saturated fatty acids o Fats II Unsaturated fatty acids o Waxes SATURATED AND UNSATURATED FATTY o Phospholipids ACIDS o Steroids ❖ Similarities Fats SIMILARITIES I Consist of carbon, hydrogen and FATS oxygen elements II Contain glycerol and fatty acids → Fats and oils are triglycerides III Contain nonpolar molecules → Triglycerides are a type of ester formed from the condensation of one 5 | CHAPTER 4 – CHEMICAL COMPOSITION IN A CELL ALIA NAZIRA ❖ Differences SATURATED FATS UNSATURATED FATS Fatty acids only have single bonds between Fatty acids have at least one double bond carbon between carbon Do not form chemical bonds with additional Double bonds can still receive one or more hydrogen atoms because all bonds between additional hydrogen atoms because carbon carbon atoms are saturated atoms are unsaturated Exist in solid form at room temperature Exist in liquid form at room temperature e.g., butter and animal fat e.g., olive and fish oil Wax ▪ Contains one molecule of alcohol that combines with another molecule ⌂ Fats fatty acid 1 Function as reserved energy ▪ Waterproof 2 Function as a liner to protect Phospholipid 3 internal organs