Download cells - Bio5090

BIOLOGY
• Biology is the study of living things.
• Examples of living things are humans and
trees.
• Living things are found everywhere in the
world – on land, in the air, in the sea and
even underground!
• Another term we can use to call living
things is organism.
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Characteristics of Living Things
• Living things are called organisms. The
three large groups of organism are green
plants, non-green plants and animals.
• There are 8 characteristics that are
exhibited by all living things.
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1.Movement
This is more apparent in animals than in plants since
animals are able to move from place to place by using
their limbs or appendages. For plants, parts move in
response to stimuli.
2.Excretion
This is the process by which metabolic waste
substances are removed from the organism.
3.Respiration
This refers to the oxidation of food substances for the
release of energy in living things. The energy is used for
movement, growth, reproduction, etc.
4.Irritability
Animals and plants are sensitive to any changes in the
environment (i.e. light, sound, touch, temperature, etc.)
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5.Growth
This can also be defined as development; or an
increase in size and mass of an organism.
6.Reproduction
This is the ability to produce new generation of
offspring.
7.Adaptability
This is the ability to adjust and adapt to changes in the
environment in order to increase the chances for
survival.
8.Nutrition
This is the process by which living things take in or
make their own food in order to release energy used to
carry daily activities.
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CELL STRUCTURE AND
ORGANISATION
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Lesson 1
Learning Objectives
1.Understand that cells are the building block of life.
2.Identify the cell membrane, nucleus and cytoplasm in an animal cell.
3.Identify the cell wall, cell membrane, sap vacuole, cytoplasm, nucleus and
chloroplasts in a plant.
4.Construct a table of similarities and differences between plant and animal cells.
5.Describe the functions of different parts of an animal and plant cell.
6.State the function of the cell membrane in controlling the passage of substances
into and out of the cell.
Outline

Cell

– Animal and plant cells
Structures and functions
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Cells
• All living things are made of cells. Cells are the
building blocks for all living things.
• A cell is a basic unit of life.
• Most living things are made up of many cells and
they called multi-cellular.
• For example, an adult human has 10 - 100 trillions
of cells in the body.
• However, some living things have only one cell and
these are called uni-cellular.
• For example, an amoeba is a one-celled organism.
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• Although cells come in different shapes and sizes, they
have several common features.
• These common features include the protoplasm, which is
made up of nucleus, cytoplasm and cell membrane.
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Animal Cell
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Plant Cell
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Structures & Functions
Structure
Function
Nucleus
Contains genetic material and controls all
chemical reactions.
Cell
membrane
Controls what passes into and out of the cell. It
is partially permeable.
Cytoplasm
A place where chemical processes take place.
Cell wall
Fully permeable. It also provides support and
gives shape to the cell.
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Structure
Function
Chloroplast
Contains a green pigment called,
chlorophyll which absorbs sunlight for
photosynthesis.
Vacuole
Storage bins. It may store food, or waste
products. In plants, vacuole may also be
used to store water, hence, maintaining
the shape and structure of the cell.
Mitochondrion
Also known as the “power house”. It
releases energy in a process called
respiration.
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Past Year Question
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Summary
Draw a table to show the structural similarities
and differences between a typical animal cell
and a typical plant cell.
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Lesson 2
Learning Objective
1.State, in simple terms, the relationship between cell function
and cell structure for the following:
• absorption – root hair cells;
• conduction and support – xylem vessels;
• transport of oxygen – red blood cells.
Outline

Cell Specialisation
– Root hair cell
– Xylem vessels
– Red blood cell
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Cell Specialisation
• Although it is useful to think about the general
features of plant and animal cells, all cells in
living organisms display specialised features that
make them suited to carrying out their very
specific jobs.
• For example, root cells, stem cells and leaf cells
within a plant. A complex organism can be
compared to a factory production line with different
people performing different tasks.
• Cells within an organism display a similar division
of labour to make the whole organism work
properly and at a high level of efficiency.
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The following
illustration shows
a variety of
animal and plant
cells, with
different shapes
and structures.
Each has a very
specific job,
which helps the
organism as a
whole to work
efficiently.
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Root hair cell
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Root hair cell
Function:

To absorb water and mineral salts from the soil.
Adaptations:


The root hair cell is long and narrow to increase
the surface area of the cell for faster absorption
of water and mineral salts.
The root hair cell has a large vacuole which
contains high concentration of salts and sugars
to draw in water by a process called osmosis. 20
Xylem vessel
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Xylem Vessel
Functions:


To transport water and minerals salts upward from the roots to
the leaves.
To provide mechanical support to the plant.
Adaptations:


Absence of protoplasm and cross wall to allow water to move
through the lumen easily.
Wall has lignin (hard substance) to prevent the xylem vessel
from collapsing
–
When xylem vessels are bundled together, it prevents
the plant from collapsing
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Red blood cell
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Red blood cell
Function:

To transport oxygen from the lungs to the rest of the
body.
Adaptations:

Flattened, biconcave shape to increase surface area for
fast movement of oxygen into and out of the red blood
cell (diffusion).

No nucleus to give space for haemoglobin.

Contain haemoglobin to transport oxygen.
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Past Year Question
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Cell Specialisation
1.Draw and label a root hair cell and a red blood
cell. (5)
2.What is the function of root hair cell? (1)
3.What are the adaptations of root hair cell that
allows it to carry out its function? Explain.
(4).
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Lesson 3
Learning Objective
1.Differentiate cell, tissue, organ and organ system and
state the examples in both animal and plants.
Outline

Cell

Tissue

Organ

Organ system
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Cell Organisation




In unicellular (single cell) organisms, the single cell
performs all life functions. It functions independently.
However, multicellular (many cells) organisms have
various levels of organisation within them.
Individuals cell may perform specific functions and
also work together for the good of the entire organism.
The cells become dependent on one another.
Multicellular organisms have 5 levels of organisation
ranging from the simplest to the most complex.
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Cells
A cell is a basic unit of all organisms consisting of
cytoplasm bounded by a membrane and is
usually with a nucleus.
eg. human cheek cell, epidermal cell, muscle cell
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Tissues
A tissue is a group of cells with similar origin,
structure, and function.
There are 4 basic types of tissues:

Connective tissue

Muscle tissue

Nervous tissue

Epithelial tissue
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Organs
An organ is made of different tissues working
together to produce a particular function.
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Organ system
An organ system is a
collection of different
organs working
together to perform a
particular function.
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There are 11 organ systems in humans
• Circulatory
• Digestive
• Muscular
• Skeletal
• Nervous
• Reproductive
• Respiratory
• Endocrine
• Immune
• Integumentary
• Excretory
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Organism
An organism is a collection of organ systems
working harmoniously together.
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Past Year Question
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Cell Organisation
_______ are the building blocks of life.
When we have a group of similar cells working together this is
called a __________, for example muscle tissue is made up of
lots of _________ cells. All the cells in a tissue look the same
and perform the same job.
A group of different tissue working together to do a specific job
is known as an __________. Examples of organ are ________
and _________.
Different organs working together form an ____________, heart
and blood vessels work together as part of our __________
system.
All of our organ systems put together make up a living _________
that is you!
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