Download 7A Booklet 2011

Unit 7A
Cells: The Body’s Building Bricks
Name: ……………………………..
Year 7: …………
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Unit 7A- Cells: The Body’s Building bricks
Dead or Alive?
There are seven things that all living organisms do, these are called “life processes”.
An organism is only alive if it does all seven life processes remembered by the jollyism “MRS NERG”.
M
R
S
N
E
R
G
Movement: Moving parts of the body
Reproduction: Producing offspring
Sensitivity: Responding and reacting
Nutrition: Getting food to stay alive
Excretion: Getting rid of waste
Respiration: Turning food into energy
Growth: Getting to adult size
Organisms are just living things:
All living things are made up of tiny building blocks known as cells.
These can be seen through a microscope but it helps if you stain them first.
There are two types of cell you need to know about: animal and plant cells
Animal and Plant cells:
Cells are like tiny bags of liquid with a thin skin or membrane around them. They come in all shapes and sizes,
but we know that most cells have a nucleus, cytoplasm and a cell membrane. Each part of a cell has its own job.
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Cells, Tissues, Organs and Organ systems:
Cells:
Cells are the building blocks that make up all living things.
Tissues:
Animal cells and plant cells can form tissues, like muscle tissue. A living tissue is made from a group of cells
with a similar structure and function, which all work together to do a particular job. Here are some examples of
tissues:
 muscle
 the lining of the lungs
 phloem (tubes that carry dissolved sugar around a plant)
 root hair tissue (for plants to take up water and minerals from the soil)
Organs:
An organ is made from a group of different tissues, which all work together to do a particular job. Here are
some examples of organs:
 heart
 lung
 stomach
 brain
 leaf
 root
Organ systems:
An organ system is made from a group of different organs, which all work together to do a particular job. Here
are some examples of organ systems:
 circulatory system
 respiratory system
 digestive system
 nervous system
 reproductive system
 leaf canopy
The plant organs:
Flower:
It contains the organs of plant sexual reproduction
Stem:
It is the organ which holds the leaves upright in the air and facing the light
It carries water and minerals to the leaves, and food around the plant. The stem is
therefore important for nutrition, excretion and growth.
Leaf:
It’s the organ of photosynthesis. A leaves contain chlorophyll which uses light energy to
change CO2 and water into glucose and oxygen. It’s therefore important for nutrition and
excretion.
Root:
It’s the organ that provides anchorage for the plant.
With its root hairs it provides a big surface area to help take in water and minerals from
the soil. The root is therefore important for nutrition.
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Specialised cells:
You should be able to work out special features of a cell from a drawing, if you are told what the cell can do.
The tables below show examples of some specialised animal and plant cells, with their functions and special
features.
Type of animal cell
Function
Special features
Red blood cells
To carry oxygen


Nerve cell
To carry nerve impulses to different 
parts of the body

Large surface area, for oxygen to pass
through
Contains haemoglobin, which joins
with oxygen

Long
Connections at each end
Can carry electrical signals
Female reproductive cell
(Egg cell)
To join with male cell and then to
provide food for the new cell that's
been formed


Large
Contains lots of cytoplasm
Male reproductive cell
(sperm cell)
To reach female cell, and join with
it


Long tail for swimming
Head for getting into the female cell
Type of plant cell
Function
Special features
Root hair cell
To absorb water and minerals

Large surface area
Leaf cell
To absorb sunlight for
photosynthesis


Large surface area
Lots of chloroplasts
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New from old:
All living things grow by cell division. Cells in our bodies are being replaced all the time.
Existing cells make new cells in an orderly way by:
1- Growing - the cell grows.
2- Duplicating – the chromosomes (which contain all the information about the cell) duplicate and the nucleus
divides.
3- Dividing – the two nuclei go to opposite sides of the cell. The cytoplasm and the rest of the cell splits into
two. These cells go on and on splitting. This makes more cells, so the organism grows, or repairs the damaged
tissue.
Reproduction of flowering plants:
A flower is the reproductive system of a plant. Flowering plants reproduce sexually. Sexual reproduction
requires the presence of male and female parts.
The male part of the flower is the stamen. It is formed of an anther and a filament. Anther produces the pollen
of a flower. Pollen grains contain the sperm.
The female part of the flower is the pistil. It is formed of stigma, style and ovary. The ovary contains the eggs or
ovules.
Pollination is the transfer of pollen from the male part of a flower to the female part.
If pollination happens in the same flower, we call it self-pollination. If it happens among different flowers, it is
called cross-pollination.
When pollen reaches the stigma of a flower (carried by wind, insects, birds…), it starts to grow a pollen tube.
Then the pollen grain starts moving down the tube to reach the ovule inside the ovary where fertilization takes
place.
Fertilization is the joining of the male sex cell (sperm) with the female sex cell (egg). Fertilization in plants
results in the formation of seeds.
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Q1:
Unscramble these words.
garno: _____________________
terha: _____________________
suseti : _____________________
toro: ______________________
lecl: ______________________
percosomci: _________________
Q2:
1- Fill in the blank.
_________________ are formed from groups of cells of the same type. ________________ are made when
different tissues work together. The circulatory _____________ consists of blood vessels and the heart.
2- Name a type of tissue that is found in the heart. ____________________
3- Which of these organs are found in plants and which in animals?
Leaf : _______________________
Heart: _______________________
Lung: _______________________
Root: ________________________
Q3:
Label the organs on the diagram of the plant.
Q4:
Label the tissues on the diagram.
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Q5:
Complete these sentences:
All plants and animals are made of tiny bits called _____________________ .
To see cells, we need a _____________________ .
We call a group of similar cells a _________________________ .
An _____________________ is made of several _______________________ .
Q6:
We use lenses and microscopes to make things look bigger than they really are. We say that we magnify them.
1- Look at the pictures. Leon drew the ladybird larger than life. Why?
__________________________________________________________________________________________
2- Work out how much larger than life Leon’s drawing is. First, measure the length of each ladybird.
The real ladybird is _______________ mm long.
The ladybird in Leon’s drawing is _______________ mm long.
So the drawing is ______________ times as big as the real ladybird.
3- Leon also drew the lady bird 20 times as big as it really was. This drawing was ______________ mm long.
4- Draw this ladybird in the box below.
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Q 7:
1- Label the parts of the microscope using the key words provided.
Key Words
coverslip diaphragm illuminator
stage eyepiece arm base
fine adjustment coarse adjustment
objective lenses revolving nosepiece
clips slide
2- Match the parts of the microscope to the definitions below.

Specimen is positioned on this.
________________________

Brings specimen into view without fine detail.
________________________

Used to shine light on object being viewed.
________________________

Holds lenses of different strengths, revolves.
________________________

Hold slide in position on stage.
________________________

Covers specimen on slide.
________________________

Adjusts light (brightness).
________________________

Joins base to nosepiece.
________________________

Eye is positioned on this to view object.
________________________

Turning this knob brings fine detail into focus.
________________________

Magnify specimens, various magnifications.
________________________

Stand or “bottom” of microscope.
________________________

Slide is positioned on this.
________________________
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Laboratory activity: Observing onion cells.
Before you can look at onion cells under the microscope, you must peel off a very thin layer:
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Q 8:
Fill in the missing values.
Eyepiece
×5
×10
×20
Objective lens
×10
×20
×40
×10
×20
×40
Total magnification
× 200
×400
×800
× 200
×450
×600
×5
×15
×15
Q 9:
The following box contains the names of 4 different types of cells:
leaf cell
nerve cell
red blood cell
root cell
1- Write the name of one of the above cells that you would expect to find in:
i) an animal: _________________________
ii) a plant: ________________________
2- Choose words from the box above to identify each of the following cells.
A= _________________________________
B= ______________________________
C= _________________________________
D= ______________________________
3- What does cell C contain that is not present in any of the other cells? ________________________________
4- What is missing from cell B that is found in all the other cells? _____________________________________
5- Which instrument do we use to observe cells in details? __________________________________________
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Q 10:
1- Name the organs in the diagram below using words from the box.
brain
heart
intestines
lung
stomach
A __________________________
B __________________________
C __________________________
D __________________________
E __________________________
2- Which of the above organs:
i) pumps blood around the body? ____________________________
ii) helps to digest food? ____________________________________
iii) absorbs digested food into the blood? ______________________
iv) absorbs oxygen from the air? _____________________________
v) controls what the body does? ______________________________
Q 11:
1- What does each of the special cells do? Fill in this table (the first one has been done for you).
Type of cell
Job of cell
Special features
Ciliated epithelial cells
Cleans dust out of the lungs
Tiny hairs
Nerve cell
Red blood cell
Root hair cell
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2- A nerve cell is an unusual shape, but it has the same cell parts as other animal cells. What are the cell parts
labelled on this diagram?
Q 12:
Comparing
When you are asked to compare things, you need to look for things that are the same or similar. So when you
compare plant and animal cells you could say:
Animal and plant cells both have cytoplasm.
1- Copy and complete these sentences:
Animal and plant cells both have a ____________________.
Animal and plant cells both have a ____________________ _____________________.
Contrasting
When you contrast things you are looking for differences.
You can do this as a table or list:

A plant cell has a cell wall, but an animal cell hasn’t.

A plant cell has a fixed shape, but an animal cell doesn’t.

Some plant cells have chloroplasts, but an animal cell hasn’t.
2- A plant cell also has a vacuole.
Write down your own sentence like the ones above to contrast this with an animal cell.
__________________________________________________________________________________________
3- How are plant cells and animal cells different?
Copy the table and write down their differences.
Plant cell
Animal cell
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4- This is Charlie’s answer to question 2.
The information is correct.
A plant cell has a cell wall.
A plant cell has a vacuole.
Explain why he got no marks.
__________________________________________________________________________________________
Q13:
1- Complete these sentences to describe the cell cycle.
a) The ___________________ divides, then the cell.
b) The new cells take in ____________________ so that they can grow.
c) Then each cell _______________ again.
d) Some cells change as they ________________. They become __________________ to do different jobs. For
example, some cells grow into muscle cells. Others become nerve cells.
2- Complete the labels on the diagram.
Q 14:
Fill in the blank.
Pollination happens when _____________ cells from an anther are carried to a female _______________.
____________________ happens when the pollen cell, which carries genetic information from the male part of
the plant, and the egg cell, which carries genetic information from the female part of the plant, join to make a
unique individual plant. The pollen and the egg are specialised cells.
Q 15:
Why is it necessary for a pollen tube to develop for fertilisation to take place?
__________________________________________________________________________________________
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Q 16:
1- This diagram shows a pollen grain growing a pollen tube.
Label it.
2- Complete these sentences:
Pollen tubes usually grow when they stick to the _____________________ of a flower. You can sometimes get
pollen to grow tubes if you put it on a microscope slide with _________________ water.
Q 17:
Starting with the seed, describe the main sequence of events in the life cycle of a flowering plant.
Q 18:
Find out what conditions are needed for a pollen tube to grow.
__________________________________________________________________________________________
__________________________________________________________________________________________
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