أوراق عمل مراجعة Cells and Life العلوم منهج انجليزي الصف السادس

أوراق عمل مراجعة Cells and Life العلوم منهج انجليزي الصف السادس

Lesson 1: Cells and Life

Revision Notes

Key Words

Cells — basic functioning unit of living things

— a device used to magnify (make bigger) any (object under observation)

Magnification — the number of times the object gets bigger under the (e.g. 1000x means the object gets bigger times)

Light microscope that uses light to see the specimen and has a lower magnification

Electron microscope — a that uses beam of electrons and has a higher magnification

Living things — include all forms of bacteria, fungi, protists, plants, and animals and have characteristiß of life (MRSGREN)

Hierarchy — arrangement from simple to complex

Unicellular — made up of one cell

Multicellular — made up of many cells

. Prokaryotic — cell without the nucleus and the genetic information (DNA) is freely floating on the cytoplasm

. Eukaryotic — cell where the DNA or the genetic formation is within the nucleus

. Homeostasis — ability to maintain constant body

. Stimuli — anything that causes a response

. Extemal stimulu/ stimuli — changes that outside the tXdy and is passes. to us through our sense organs (eyes, nose, ears, tongue, skin) e.g. levels of sunlight

. Internal stimuli — any change that happens within the body e.g changes in blood sugar levels

 

CHARACTERISTICS OF LIVING THINGS

 For a living thing to be called living thing, it must possess ærtain characteristics

• Such characteristics are

Movement

Respiration

Sensitivity

Homeostasis

Growth & Reprcxiuction

Excretion

Nutrition

1. Living things are organized

 Living things are organized from simple to complex

Organization starts frorn cells* tissues* organs* organ systems organism

2. Living things grow and develop

Living things grow and develop

• Growth refers to the increase in size

 Development refers to the growth in mental and other skills

3. Living things

Reprcxiuction is the ability to make offsprings similar to the parents

• It can sexual and asexual reproduction

4. Living things to stimuli

 Stimuli are changes that happen either inside or outside the bcxiy that the living things have to respond to

 Internal stimuli are that happen inside the human txxiy such as hunger, changes in sugar levels etc

 External stimuli are changes that happen outside the human body such as light levels, sound etc Response is the result or the outcnrne Of the stimulus

. Living things maintain internal conditions

 Homeostasis is the ability to maintain stable internal cnnditions

 Humans need to maintain constant

cnnditions such as: water levels, blood sugar, PH, temperature in order to survive

6. Living things use energy

• Living things need energy to survive

 

1. Light Microscope

• uses a light source to focus the object

 It only has a magnification up to 1500 x which means that the object will only be bigger by 1500 times the original size

2. Electron Microscope

 Uses beam of electrons to focus the object

 It can magnify up to 100,000 x the original size of the object

TYPES OF ELECTRON MICROSCOPE

I. Scanning Electron Microscope (SEM)

 Here the electrons pass the object and after reflected or bounce off the specimen to create a 3-D image

. Transmission Electron Microscope (TEM)

• Here the electrons are transmitted or is absorbed by the object

CELL THEORY

Robert Hooke

 First person who investigated the cells using a cork stem

Image Of Robert Hooke “Cork” cells

 

Anton van Leeuwenhoek

 Made the microscope that is more powerful than the one used by Robert Hooke

 He also studied cells from rain water and discovered animal cules

CELL THEORY

I. All thing things are made up of cells

. Living things are the basic functioning unit of life

 All cells come from pre-existing cells. (e.g. when we are wounded, the wounds heal)

TYPES OF CELLS according to Number

. Unicellular — only one cell, bacteria are the best example of unicellular organisms

. Multicellular — consists of many cells, cells of plants, animals, protists, and fungi are all multicellular

THREE BASIC PARTS OF THE CELL

1. Nucleus

2. Cytoplasm

the central part of the cell. the control center or the “brain- the cell because it is the one that controls all the activities within the cell

it contains the genetic information called the DNA that is responsible for the traits that parents pass to the offspring

The fluid or the watery part of the cell

This is where all the parts of the cell are found

In the cytoplasm. all chemical reactions take place such as the photosynthesis and respiration

3. Cell Membrane

• The outer part of the cell

 It is the one that controls what comes in and out of the cell (including oxygen. carbon dioxide. waster materials etc)

• It is like a security guard

 

TYPES OF CELLS ACCORDING TO THE LOCATION OF DNA

 These are organisms that do not have nucleus but they do have the DNA or the genetic material

 The genetic material or the DNA is not by the nucleus but it is Iwated on the cytoplasm

 Moreover. they do not have organelles (or parts)

 They are typically smaller than eurkaryotes

 are the example of prokaryotic

 They have a definite nucleus where the DNA is found inside

 They also have membrane- tmnd organelles

 All forms of plants, animals, fungi and protist are eukaryote

CLASSIFICATION

All living things need to The biggest level of classification is the Dornain

Kingdom is the next level of classification to Domain

There are domains

Domain Archaea

Domain Bacteria

Domain Eukarya

There are Six Kingdoms of Living Things

Kingdom Archaea

Kingdom Bacteria

Kingdom Protista

Kingdom Fungi

Kingdom Plantae

Kingdom Animalia