Form 4 Biology Chapter 2 topical Exercise

Assalamualaikum and hello,

It’s revision time! But before you proceed with answering the following topical exercise, here is a video to help you refresh your memory on organelles and their functions.

Once you are done with your revision, please download the following handout.

https://wickedbiology.files.wordpress.com/2017/01/biology-topical-exercise-form-4-chapter-2.pdf

Good luck!!

Love ,

Tr.Rez 🙂

 

Soalan Ulangkaji Bab 2 (Tingkatan 5)

Assalamualaikum and salam sejahtera 🙂

It’s been awhile since I last posted something in this website. I’m so sorry about that. But fortunately I managed to prepare the Soalan Ulangkaji Bab 2 for form five students.

Soalan Ulangkaji Bab 2

You can download it through the following link.

SOALAN ULANGKAJI BAB 2

I hope that this handouts will help you with your revision for this chapter 🙂

Regards,

Tr. Rez

 

1.2 : The Circulatory System (Blood Vessels)

Biology Form 5 

Chapter 1 : Transport

Subtopic 1.2 : The Circulatory System (Blood Vessels)

The Structure of Human Blood Vessels

Hand blood vessels

Hand blood vessels

 

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  • Blood vessels are the tubes for the medium to flow through
  • Three main types of blood vessels are
    1. Arteries
    2. Capillaries
    3. Veins
  • Each type of blood vessels has different structure according to their functions

 

 

 

 

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a) Arteries

  • Functions: carry blood away from the heart towards other tissues and organs
  • When an artery enters an organ, it divides into smaller branches called arterioles

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  • The wall of an artery has three layers
    • Endothelium
      • Innermost layer
      • consists of a single layer of endothelial cells
    • Tunica media
      • Thick middle layer
      • consist of elastic fibres & smooth muscles
    • Tunica Externa
      • Outermost layer
      • Consists of collagen fibres
  • Thick walls can withstand the high pressure of blood inside the arteries

b) Veins

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  • are large vessels which carry blood back to the heart
  • receive blood from small blood vessels called venules
  • possesses less smooth muscle tissues than an artery
  • have thinner walls than arteries because blood pressure in the veins is  much lower than in the arteries
  • lumen in the centre of a vein is larger in diameter than in an artery
  • semilunar valves in the vein prevent backflow of blood, thereby maintaining a one-way flow of blood towards the heart

 

 

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c) Capillaries

capillary

  • the smallest and most numerous blood vessels
  • comprises of a single layer of endothelial cells
  • tiny gaps between the endothelial cells allow water, ions and small solute molecules to leak out of the capillaries
  • the site of exchange of materials between the tissues and the blood
  • erythrocytes and large protein molecules are unable to leak out of the capillaries
  • leucocytes can squeeze through the capillary wall into the tissue spaces

 

Compare and contrast arteries, veins and capillaries

Similarities

  • Walls consist of epithelial tissues, smooth muscles and connective tissues (except capillaries)
  • Carry blood

Differences

1.2 The Circulatory Sytem (Blood Vessels & Heart)

 

 

 

 

 

 

2.1 Cell Structure & Function

Biology Form 4

Chapter 2: Cell Structure and Cell Organisation

Subtopic 2.1: Cell Structure & Function

Introduction to cells.

 

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What are cells?
  • are basic units of living organisms
  • Consist of Protoplasm:
    • living component of a cell
    • surrounded by a thin layer called the plasma membrane
    • made up of cytoplasm & nucleus
    • contains small structures called organelles
  • Most of the organelles can only be seen using an electron microscope
  • Plants cells have an outer layer called the cell wall
Animal Cells

Animal Cells

Plant Cells

Plant Cells

Cellular Components of Animal and Plant Cells

Cellular components can be classified into organelles or non-organelles

Organelles

a) Nucleus

  • cell-nucleus-5-638Functions :
    • Controls all activities of the cell
    • Nucleolus is involved in the synthesis of ribosomes and ribonucleic acid (RNA)

 

 

 

b) Mitochondria

biobook_cells_4

  • Functions :
    • Sites of cellular respiration
    • Enzymes involved in cellular respiration to help oxidise glucose to release energy in the form of ATP (Adenosine TriPhosphate)

 

 

c) Endoplasmic reticulum (ER)

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  • Two types of ER
    • Rough Endoplasmic Reticulum (RER) – has ribosomes on its surface
    • Smooth Endoplasmic Reticulum (SER) – has no ribosomes on its surface
  • Functions :
    • RER transports proteins synthesised by ribosomes
    • SER synthesises lipids and is the centre for detoxification of drugs

 

d) Golgi apparatus

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  • Functions :
    • Centre for processing, packaging and transporting macromolecules such as proteins and carbohydrates

 

 

 

e) Ribosomes

ribosome

  • Functions:
    • Sites of protein synthesis

 

 

 

f) Lysosomes

lysosome

  • Functions :
    • Break down macromolecules such as proteins, lipids, nucleic acids, polysaccharides as well as worn-out organelles

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g) Vacuoles

Vacuole

  • Usually found in plants cells, in animals cells, if vacuoles are present they are small
  • Functions :
    • Store food substances such as sugars and amino acids
    • Site for waste products
    • Regulate water balance in cells
    • Turgidity of cells gives support to plants

 

 

h) Centrioles

centriole

  • Only found in animal cells
  • Functions:
    • Form spindle fibres during cell division

 

 

i) Chloroplast

010_chloroplast

  • Only found in green plants
  • Functions :
  • Site for photosynthesis
    • Chlorophyll traps light energy for photosynthesis

 

 

 

Non-organelles components

a) Plasma membrane

plasma-membrane

  • Functions :
    • Regulates and controls the movement of substances in and out of the cells
    • protects the cell by separating the content of the cell from its environment

 

 

b) Cytoplasm

Cytoplasm

  • Functions :
    • Place where biochemical reactions occur

 

 

 

 

 

c) Cell wall

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  • Only found in plant cells
  • Functions :
    • Maintain the shape of plant cell
    • protects the cell from bursting
    • gives support to cells

 

 

 

SUMMARY

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Comparing and contrasting the structure of animal and plant cells

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compare-contrast-cells

The Density of Certain Organelles in Relation to Functions of Specific Cells

What are organelles?

  • “little organs”
  • Are tiny structures inside a cell that perform specific functions for the cell
  • 3 main functions of organelles:
    • Carry out their specialized functions:
      • E.g. Mitochondria produce energy in the form of ATP
    • Acts as containers to separate parts of the cell from other parts
      • E.g. lysosomes
    • Sites for chemical reaction
      • E.g. Choloroplast

Relationship between the Density & Functions of certain Organelles

  • Plant and animals are made up of different types of cells
  • Different cells carry out different functions.
  • For example, muscle cells bring above movement while nerve cells transmit nerve impulses
  • The density of certain organelles in a specific cell is related to its specific function

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1.2 : The Circulatory System

Biology Form 5 

Chapter 1 : Transport

Subtopic 1.2 : The Circulatory System (Blood)

What is a circulatory system ?

  • A mass flow of system conveying materials to all cells of the body
  • Consists of a network of tubes (vessels) that deliver useful materials to all cells of the body and then take away their waste products
  • In mammals the circulatory system consists of :
    1. Cardiovascular system : consists of the heart, blood vessels and blood
    2. Lymphatic system : consists of lymphatic vessels and lymphoid tissues within the spleen, thymus, tonsils, lymph nodes and lymph
Diagram 1 : Cardiovascular system

Diagram 1 : Cardiovascular System

 

Diagram 2 : Lymphatic Sytem

Diagram 2 : Lymphatic System

  • A circulatory system has three components
    1. Medium : fluid that flows in the system, carrying materials around the body
    2. Vessels : a system that carries the fluid
    3. Pump : keeps the fluid moving through the vessels
The Human Blood
  • A specialised tissue consisting of several types of cells suspended in a fluid medium called plasma
  • Composition of human blood :
    1. Plasma (55%)
    2. Cellular components (45%) : platelets, white blood cells and red blood cell

The components of blood

Plasma

  • yellowish fluid in blood

plasma

  • composition may vary at different parts of the body
  • E.g : plasma in hepatic portal vein , which leads from ileum to the liver, is richer in nutrients than other blood vessels
  • about 90% of plasma is water in which a complex mixture of various substances is dissolved

Substances Transported by Plasma

Cellular Components of Blood

a) Erythrocytes (Red blood cells)

Characteristics: 

  • Biconcave disc shape :
    • provides a larger total surface area / volume (TSA/V) ratio than that of sphere and therefore increases the rate of gaseous exchange
    • makes the erythrocyte very flexible and allows it to squeeze through blood capillaries image008
  • Lack of nucleus in mature erythrocytes :
    • provides more space for haemoglobin to be packed into the cell
  • Formed in bone marrow
  • Limited lifespan about 120 days
  • Destroyed in the liver or spleen

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Functions :

  • Erythrocytes transport oxygen from the lungs to all parts of the body
    • Haemoglobin combines with oxygen to form oxyhaemoglobin
  • 98% of oxygen is carried in the blood as oxyhaemoglobin; 2% dissolved in plasma
  • Erythrocytes carry carbon dioxide from the tissues to the lungs in the form of carbaminohaemoglobin
  • Erythrocytes also function as buffers and help to maintain the blood pH

b) Leucocytes (White blood cells)

 

  • are formed in the bone marrow and lymph nodes
  • bigger than erythrocytes ; fewer in number
  • each have a nucleus

white-blood-cell

  • Divided into :
    • Granulocytes 
      • have irregularly lobed nucleus and granular cytoplasm
      • Three types : neutrophils, eosinophils and basophils
    • Agranulocytes
      • have smooth rounded /  bean-shaped nucleus
      • Cytoplasm lacks granules
      • Two types: Lymphocytes and monocytes

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c) Thrombocytes (Platelets)

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  • irregularly shaped cell fragments
  • usually lacking nucleus
  • formed in bone marrow
  • have lifespan of 5 to 9 days
  • destroyed in the spleen and liver
  • play an important role in blood clotting

 

 

 

 

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