Biology B2
Lesson 2: Bacteria
Connect: Exam Practice
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(a) The diagrams show a bacterial cell, a plant cell and
an animal cell. Structure X is found in all three cells.

(i) Complete the sentence by choosing the correct
answer. Structure X is the (1):
A cell membrane
B cell wall
C cytoplasm
D nucleus
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Connect: Exam Practice
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(ii) Many bacteria have one or more flagella whereas most
animal cells have no flagella. State one other difference
between a bacterial cell and an animal cell. (1)

(b) (i) Scientists use microscopes to magnify cells. Choose from
the following words to complete the sentences. (2)
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Focusing wheel
Light
less
more
objective lens
The magnification of a light microscope can be varied by
changing the ______________. The electron microscope can
magnify images _____ than the light microscope.
Connect: Exam Practice

(ii) The diagram shows a sperm cell that has been magnified
100000 times.

Calculate the actual length of the sperm cell. (2)
Length of sperm cell = .................................................................... mm
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(iii) Explain why a human sperm cell contains more mitochondria
than most other types of cell in the human body. (2)
Connect: Exam Practice

(a) (i) A (1)
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(a) (ii)
Any one of the following points
bacterial cells have a cell wall (animal cells
do not) (1)
bacterial cells do not have a nucleus (animal
cells do) (1)
bacterial cells have circular DNA /
chromosomal DNA (animal cells do not) (1)
bacterial cells have plasmids (1)
Connect: Exam Practice
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(b) (i) objective lens (1) more (1) (2)
(b) (ii) calculation (1)
correct answer (1)
= 0.00130 / 1.3 × 10-3 (2)
(b)(iii) An explanation including two of the
following points:
mitochondria are sites of respiration for
energy (1)
sperm requires a lot of energy (1)
for movement / swimming / to move the
flagellum (1) (2)
What Are We Learning
 By
the end of this lesson, you should:
 Be
able to describe the structure of a
bacterial cell.
 Relate
the structure to the function of a
bacterial cell.
SMSC & RWCM
 During
this lesson, you will be developing
social skills by working in groups.
 We
will be developing listening skills and
will be using key words in the correct
context.
Today’s Learning
Progress Step 1:
Label the key parts
of a bacterial cell
Progress Step 2:
Explain the function
of the key part of a
bacterial cell
Increasing Difficulty
Progress Step 3:
Compare the
function of electron
and light
microscopes
Think
 Plant
and animal cells have organelles.
 Plant
cells have some additional
organelles to animal cells.
 What
 How
does a bacterial cell look like?
can we see bacteria and other cells
so clearly?
Bacterial Cells
 Bacterial
cells are more simple than
animal and plant cells.
 They
have cytoplasm, a cell membrane, a
cell wall and genetic material.
 Draw
what you think a bacteria looks like.
This bacterial cell has a
FLAGELLUM which could be
used for movement or to
damage other cells with.
Genomic deoxyribonucleic
acid is CHROMOSOMAL
DNA. It contains the
biological information that is
passed on from one
generation to the next. It is
separate from Plasmid DNA.
A plasmid is a small DNA strand
that is separate from the
CHROMOSOMAL DNA. Plasmid
DNA is able to replicate and
carries genes that may aid the
survival of the organism.
For example: antibiotic
resistance.
Note:
This bacterial cell has NO
distinct NUCLEUS due to its
lack of a nuclear
membrane.
Many
flagella
Examiners Tip!
Bacterial cells have
a cell wall and only
one circular
chromosome but
no nucleus.
Bacteria
don’t
always
have a
flagellum
TASK:
 Draw
a bacterial cell and label it
with the following key words:
Cell
Membrane
Cell Wall
Cytoplasm
Chromosomal
DNA
Flagellum
Plasmid
DNA
Task: Copy And Complete
Feature
Cell Membrane
Nucleus
Plasmids
Chloroplasts
Cell Wall
Cytoplasm
Animal Cell
Plant/ Algal Cell
Bacterial Cell
Task: Copy And Complete
Feature
Animal Cell
Plant/ Algal Cell
Bacterial Cell
Cell Membrane
Yes
Yes
Yes
Nucleus
Yes
Yes
No
Plasmids
No
No
Yes
Chloroplasts
No
Yes
No
Cell Wall
No
Yes
Yes
Cytoplasm
Yes
Yes
Yes
Simple Microscopy
Seeing the bigger picture.
Light Microscope
Light passes through the
specimen and then through
the magnifying lenses so you
can see the object much
bigger.
Electron Microscope
Passes a beam of electrons
through the specimen to
magnify it
A light microscope
shows us bacteria
don't have a nucleus.
An electron
microscope shows us
that bacteria have
two types of DNA,
chromosomal and
plasmid DNA.
Task
 Complete
Worksheet 2.2d.
 Stick
the completed sheet into your
exercise book.
 Try
worksheet 5.4 ‘Cell Structure’.
What Are We Learning
 By
the end of this lesson, you should:
 Be
able to describe the structure of a
bacterial cell.
 Relate
the structure to the function of a
bacterial cell.
Reflection: What Do You Know
Now?
Bacteria