Science Chapter 2 Form 1 2f245k

CHAPTER 2: CELL AS THE BASIC UNIT OF LIFE

An instrument that magnifies minute objects so they can be seen easily. It is one of the most important tools of science. Physicians and biologists use microscopes to examine bacteria and blood cells. Parts of microscope : Eyepiece Magnify the specimen by 10x. Rough focus knob Change the position of the objective lens when focusing with low-powered objective lens. Change the position of the objective lens slightly for fine focusing. Used with high- powered objective lens. Magnify the size of a specimen by 4x, 10x or 40x. Stage: Place the glass slide. Clip: Hold the slide on the stage. Diaphragm: Control the amount of light entering objective lens. Mirror: Reflects light up through an opening un the stage to illuminate the specimen. Base: Stabilize the microscope. There are four basic kinds of microscopes:    

Optical or light microscope Electron microscope Scanning probe microscope Ion microscope

Structure of cell o

Function

Nucleus Control all activities of the cell o

Vacuoles

Stores salt and sugar solutions , hold waste substances o

Chromosomes

Determines how an organism behaves (genetic information) Cytoplasm A place where all chemical reactions take place o

Cell membrane

Control the movement of substances into or out of the cell Cell wall and gives the cell a regular shape o

Chloroplasts

A place where plants make food by photosynthesis. Contain chlorophyll which is used to trap sunlight for photosynthesis.    

Cell membrane Cell wall Vacuole Chloroplast

Nucleus Controls all the activities of the cell Cytoplasm A place where all chemical reaction take place. Stores dissolves material Cell membrane Controls the movement of material in and out of the cell Cell membrane Cytoplasm Comparing Animal Cell and Plant Cell Both have nucleus, cytoplasm and cell membrane. Differences between plant cells and animal cells Regular shape shape Irregular shape With chloroplasts chloroplasts Without chloroplasts With a cell wall (cellulose) cell wall Without cell wall Large vacuoles vacuoles Has no vacuole except in unicellular 1. What is the basic unit of living things?

___________________________________________________________

2. What makes up the protoplasm of a cell? ___________________________________________________________

3. What can be found in plant cells but not in animal cells? ___________________________________________________________

4. State the substances that builds up the cell wall of plants cells. ___________________________________________________________

5. Draw an animal cell and plant cell.

Review 1 : Animal Cell and Plant Cell And Animal cell

UNICELLULAR AND MULTICELLULAR ORGANISMS Made up of one cell only. “Uni” means one. A simple organism Mostly are aquatic living things(in ponds, drains and the sea). Carry out life processes inside the cell. Absorbs nutrients, expel wastes and exchange gas with their environment. Do not have circulatory system. Also known as microorganism (microbe) Examples :

Paramecium, Amoeba, yeast, Pleurococcus, Chlamydomonas. Asexual reproduction More complex than unicellular organism Examples : Human beings, birds, fish Hydra, Spirogyra, moss, earthworm, Mucor. Made up of many cell. “Multi” means many. Life process are more complex. Various types of cell work together to perform a specific task. 1. What is unicellular organism? ___________________________________________________________ 2. What is multicellular organism? ___________________________________________________________ 3. Give two examples of unicellular organism. (a) ________________________________________________________ (b) ________________________________________________________ 4. Give two example of multicellular organism. (a) ________________________________________________________ (b) ________________________________________________________ 5. Why is human being classified as multicellular organism? ___________________________________________________________ 6. Identify unicellular organisms and multicellular organisms given below. 7. Name the organism below. (a) _____________ (b) ______________ (c) __________

(d) _____________ (e) ______________ (f) __________ Review 2 : Unicellular Cell and Multicellular Cell Euglena Paramecium Spirogyra Chlamydomonas Hydra Mosquito Amoeba Moss Scorpion Cockroach Unicellular Organisms Multiicellular

ORGANISATION OF CELL IN THE HUMAN BODY Cell organization is the grouping of simple cell into more complex structures. CELL TISSUE ORGAN SYSTEM ORGANISM CELL Basic unit of life The smallest structures capable of basic life processes. Examples : Epithelium cell， Red blood cell， White blood cell， Cardiac muscle cell， Bone cell， Nerve cell， Reproductive cell， A group of similar cells that work together to perform a particular function. Four main types : - Epithelial tissue - Muscle tissue

- Connective tissue - Nervous tissue TISSUE ORGAN An organ consists of two or more kinds of tissues ed into one structure that has a certain task. 6 Examples : - The heart - The kidney - The lungs - The stomach - The liver - The brain Groups of organs form organ systems Each organ system carries out a major activity in the body. Examples : - Reproductive system - Blood circulatory system - Digestive system - Excretory system - Respiratory system - Muscular system All system in the body function in a coordinated manner to form a multicellular organism. Type of human cell Structure Respective function -Red blood cell Transports vital food and oxygen to all parts of the body. -Nerve cell

Carries messages in the form of electrical impulses around the body. -White blood cell Protects the body from damage by invaders Human sperm cell. Takes part in fertilisation to produce young ones. -Bone cell Form bones to the body and protect organs. Human egg cell If the egg is fertilised it will develop into an embryo. -Epithelial cell It protects the internal and external parts of the body. -Muscle cell Contracts and relaxes to move parts of the body.

VARIOUS SYSYEM IN THE HUMAN BODY The Lymphatic System Body‘s defences against infection. -The Skeletal System Protect internal organ. Provides body The Endocrine System Produces, stores and secretes chemical substances known as hormones. -The Reproductive System For reproduction The Nervous System Detect stimuli and responds to them. -The Blood Circulatory System

Supplies the cells of the body with the food. Transport waste product. The Muscular System Enables body movement. -The Excretory System Removes waste products from body. -The Respiratory System Supplies oxygen and aids removing of carbon dioxide -The Digestive System Processes food (ingestion, digestion, absorption). 1. State the following structures as ‘cell’, ‘tissue’, ‘organ’ or ‘system’. (a) Sperm - __________________ (b) Stomach - __________________ (c) Ovum - __________________ (d) Brain - __________________ (e) Digestive - __________________ (f) eardrum - __________________ 2. Complete the cell organization below. -------

------

-------

------

Organism

3. State the name of each organ shown below and the system it belongs to . a) Organ : __________________ System : _________________ b) Organ : __________________ System : _________________ c) Organ : __________________

System : _________________ d) Organ : __________________ System : _________________

2.1: What is a Cell?

> Basic unit (the smallest parts) of a living things.> Can only be seen through a microscope.

Nucleus: Controls cell activities, contains genetic information Cell membrane: Controls the substances that move in and out of the cell Cytoplasm: Dissolves food particles through chemical process Cell wall: Maintains the shape of the plant cell Vacuole: Stores sugar solution and mineral salts Chloroplast: Contains chlorophyll that is needed for photosynthesis 2.2: Unicellular Organisms and Multicellular Organisms

*Unicellular organisms >Consist of only one cell, usually are microorganisms.

> Can only be seen under microscope. > Live in water or wet places. > E.g. Amoeba, Euglena, Paramecium, yeast. *Multicellular organisms > Consist of many cells. > E.g. hydra, spirogyra, mucor. > Humans are the most complex multicellular organisms. 2.3: Cell Organisation in the Human Body

2.4: The Human Being – A Complex Organism

> Humans are complex organisms > Human body is made up of millions of cells > The cells are specialised to perform certain functions Chapter 2 >>> Cell as a Unit of life

-Cell is a basic unit of living things. -Each cell can function and survive on its own. Cells can perform life processes such as digestion, respiration, excretion, reproduction, growth, and response to stimuli. -Animal cell do not have definite shapes because there are no cell wall. The cell do not have chloroplasts to help manufacture food. The number of vacuoles in animal cells is very small and sometimes none at all.

-Plant cell have definite shape because the cell walls are made up of cellulose. The cell can also manufacture their own food because the chloroplasts have chlorophyll. The vacuoles of

plant



cell

are big and

fill

with cell

sap.

Unicellular organisms are organisms made up of one cell only (single cell). Examples : Amoeba, Euglena and yeast.

Euglena

Amoeba

Multicellular organisms are organsms with many cells. Multicellular organisms are more complex than unicellular organisms. Examples : Hydra, Spirogyra, human beings.

spirogyra

human being

-Both unicellular and multicellular organisms can perform similar life process. -Organisation of cell in the human body involves the following stages: Cell =>> Tissue =>> Organ =>> System =>> Organism

Cells What is the basic unit of life? In 1665, a physicist named Robert Hooke used one of the first microscopes to look more closely at the living world. A slice of cork caught his eye. Looking at thousands of tiny chambers, Hooke termed these structures cells because they reminded him of the rooms in a monastery.

Subsequent observations built upon Hooke’s work and led to what is known as the cell theory. The cell theory states the following: 

All living things are made of cells.



Cells are the basic units of structure and function in living things.



All cells are produced from existing cells.

Hooke's microscope.

How is life organized around cells? An organism may be characterized as having different levels of organization built around the cell. Unicellular organisms are made up of only one cell, while some multicellular organisms are comprised of trillions of cells. In multicellular organisms, groups of cells sharing similar structure form tissues that carry out a specialized function. Different tissue layers form organs. And separate organs often work together to carry out major bodily functions, such as digestion or circulation. These “teams” of organs are referred to as organ systems. Growth of an organism is the result of an increase in cell size and, in multicellular organisms, an increase in the number of cells.

Levels of organization.

How are cells alike? At first it might seem that the cells of such dissimilar creatures as the tiniest bacterium and a great blue whale would be very different. The cells of any organism, however, demonstrate all the characteristics of life: a life span that includes a living beginning, growth, development, reproduction, and death; the constant use of matter and energy; response to changing internal and external conditions; and the presence of DNA. Although multicellular organisms can have diverse cell types, all cells have certain parts in common (see the interactive cell picture below). All cells are bound by a cell membrane and contain cytoplasm, which is where the cell parts lie. The nucleus of this cell contains the hereditary molecule DNA, which is also found in all cells. And, all cells contain ribosomes, which are so tiny that they can’t be seen in this cell. Ribosomes are structures that are responsible for constructing proteins—the molecules that carry out the instructions contained in DNA.

Cytoplasm | Nucleus | Cell Membrane Roll your mouse over the names of the parts to see them in the picture.

How are cells different? One of the most basic distinctions among life forms involves the cell. In some cells, including those of plants, animals, fungi, and protists, the DNA is contained in a nucleus, which is itself a membraneenclosed body. Cells that contain a nucleus are called eukaryotic (“true nucleus”) cells, and the organisms with cells of this type are called eukaryotes. Within the cytoplasm of a eukaryotic cell, there are numerous compartmentalized bodies called organelles. Organelles serve specific purposes within the cell, ranging from building proteins to making energy. Different types of organisms may have different sets of organelles. Organisms that photosynthesize, like plants, contain chloroplasts, for example. There are cells that aren’t as structurally complex as those with a nucleus. Prokaryotic (“before the nucleus”) cells lack a nucleus and organelles. Most single-celled organisms are prokaryotes that are known as bacteria and archaea. Prokaryotes are still capable of performing many of the same types of functions as eukaryotes. These functions occur in the cytoplasm instead of in organelles. In fact, many bacterial and archaeal cells are capable of carrying out very complicated biochemical reactions that allow them to harvest food and/or energy from very unlikely sources, such as pollutants and poisons.

CHAPTER 2: CELL AS A UNIT OF LIFE Questions 1 The diagram below shows a plant cell. Which of the following structures A, B, C or D makes chlorophyll which is required for plants to make food? 2 The figure below shows cell X. Based on the structures M and N in cell X, complete the following table. Name of structure: Function of structure: 3 The following figure shows a plant cell. (a) On the above figure, label structures P, Q and R using the following words . (b) Draw lines to show the correct match between the structures and their functions. Draw the lines as shown below. Structure: Function: P: Q: R: - Vacuole Cell wall Nucleus -Holds cell sap in plants -Controls all activities of the cell -Protects and maintains the shape of the cell -Makes chlorophyll which is required for plants to make food

Answers

1B 2 Name of structure Function of structure M (Nucleus) Controls all the activities in the cell N (Chloroplast) Makes chlorophyll which is required for plants to makes food 3 (a) P: Nucleus Q: Cell wall R: Vacuole (b) Q – Protects and maintains the shape of the cell R – Holds cell sap in plants

Science and technology [edit]

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Cell (biology), the functional basic unit of life

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Cell (database), a unit in a statistical array (as a spreadsheet) formed by the intersection of a row and a column

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Cell (EDA), a term used in an electronic circuit design schematics

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Cell (geometry), a three-dimensional element, part of a higherdimensional object

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Cell (journal), a scientific journal

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Storm cell, the smallest unit of a storm producing system

Technology [edit] -Cell, a wireless connection within a limited area, referred to as a cell, or a Basic Service Set (BSS) -Cell (microprocessor), a microprocessor architecture developed by Sony, Toshiba, and IBM -Cell, a basic unit of a cellular automaton -Cell or mobile phone, a phone connected to a cellular network -Cell, area of radio coverage in a cellular network -Cell, the basic unit of Flash memory -Electrochemical cell, a device used to convert chemical energy to electrical source of energy -Galvanic cell or Voltaic cell, a particular kind of electrochemical cell -Cell, a fixed length, small (53 byte), data frame used in the Asynchronous Transfer Mode protocol

Entertainment and media [edit]

Fiction [edit] -Cell (comics), a Marvel comic book character

-Cell (Dragon Ball), a fictional supervillain in the Dragon Ball universe -Cell (novel), a 2006 horror novel by Stephen King

Music[edit] -Cell (album), a 2004 album by the Japanese rock group Plastic Tree

-Cell (band), a New York-based band -Cell (music), a small rhythmic and melodic design that can be isolated, or can make up one part of a thematic contex, a 1998 album by Cex

Society and religion [edit]

-Cell, a group of people in a cell group, a form of Christian church organization

-In Cenobitic monasticism, a room or hut in which a monk or nun lives -Cell, a unit of a clandestine cell system, a penetration-resistant form of a secret or outlawed organization -Prison cell, a room used to hold people in prisons

See also [edit]

-CEL (disambiguation) -Cellular (disambiguation) -Macrocell -The Cell (disambiguation)

The Cell is a 2000 psychological thriller film starring Jennifer Lopez. The Cell(s) may also refer to 

"The Cell" (song), by Jandek



U.S. Cellular Field, also known as "The Cell", a baseball stadium in Chicago



The Cells, a rock band



Molecular Biology of the Cell, a textbook published by Garland Science



"The Cells", a 2004 song by The Servants



"The Cell" (Hydrogen system), by The Cell Inc



"The Cell" (The Vampire Diaries) - An episode of the TV series The Vampire Diaries

See also [edit] 

Cell (disambiguation)

CEL (disambiguation)

The Cells Origin

Chicago

Genres

Rock, Indie rock, Pop punk

Years active

1998–present

Labels

Old Reliable Records, Orange Recordings



Cory Hance Johnny Furman Mark Doyle

Past

Brede Hovland



Randy Payne Pat McIntyre Rick Ness

The Cells are a 3-piece rock band based inChicago, currently made up of singer/guitarist Cory Hance, bassist Johnny Furman and drummer Mark Doyle. The band were formed in 1998 by singer/guitarist Cory Hance and bassist Brede Hovland. Hovland then dropped out to work in the movie business, and

Hance, guitarist/singer Pat McIntyre and drummer Randy Payne continued the band with guest bassists such as Rick Ness, formerly of Fig Dish (a key Cells member during his stint),Skid Marks, of Box-O-Car, Josh James and Bob Rising . They released their debut album,We Can Replace You under Orange Recordings. After touring behind We Can Replace You as a 3-piece, Hance, McIntyre and Payne parted ways. Payne and McIntyre formed the band Cisco Pike. Hance recruited drummer Mark Doyle (formerly of Loud Lucy, Verbow and Woolworthy) and bassist Johnny Furman (formerly of The Webb Brothers, The Lupins and the Darlings) in late 2003. The new Cells lineup completed the band's second CD Mayday in 2006, available on their own imprint, Old Reliable Records. Discography[edit]

Studio albums[edit] Year

Album

Label

2002

We Can Replace You

Orange Recordings

2006

Mayday

Million Yen Studios