Download lesson-8-pro-and-euk-cells

Starter
Using page 19 first few paragraphs under the
prokaryotic cells title work out the answers
to the following
1. Give definitions of the terms prokaryotic
and eukaryotic cells
2. Which do you think evolved first
eukaryotic or prokaryotic cells?
Learning objectives
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Recall the differences between prokaryotic
and eukaryotic cells
Describe the differences in the DNA of
these cells
Create a hypothesis of eukaryotic cell
evolution - hwk
Bacterial cells –prokaryotic
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Still show all the characteristics of living
things
Sheet to fill in as we go through the
differences in the structure
Membrane
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Prokaryotic cells have only one membrane at
the surface – cell surface membrane
You should be able to put 7 no’s in the
prokaryotic column of your table
Nuclear membrane, mitochondria,
chloroplasts, ER, golgi, nucleus and golgi
vesicle
Cell wall – always present
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Made of peptidoglycan instead of cellulose
Peptidoglycan often called murein
Ribosomes – always present
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Smaller than those of a eukaryotic cell
20nm in prokaryotes (70s)
30nm in eukaryotes (80s)
DNA
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In the form of a single loop = circular
Eukaryotic DNA is in strands = linear
Many prokaryotes have additional loops of DNA
called plasmids (not essential for life)
In eukaryotic cells histone proteins attach to the
DNA strand
In prokaryotic cells no histone proteins
No nucleus in prokaryotic cells but general area
that the main DNA is found is called the nucleoid
Energy production
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No mitochondria but energy needs to be
released just the same
Cell surface membrane has infolded regions
called mesosomes
Enzymes for respiration
Some can photostnthesise
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No chloroplasts
Photosynthetic forms do have membraneous
vesicles where photosynthetic pigments
(chlorophyll molecules) are located. These
structures are called thylakoids.
Flagella
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Eukaryotic and prokaryotic flagella have
different internal structures
Function is the same – movement of cell
3 main differences
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Nucleus
DNA
Organelles
Typical exam questions
1.
Complete the table to prokaryotic
show 3 ways in which
prokaryotic and
eukaryotic organisms
differ in the structure
of their cells
eukaryotic
2.
(i)
(ii)
The table below
compares the features
of typical eukaryotic
and prokaryotic cells
Complete the table by
placing a tick, cross or
sometimes present (4)
Outline the roles of the
golgi apparatus and the
ribosomes (2)
Eukaryotic
cell
Prokaryotic
cell
Cell wall
Sometimes
present
√
Nuclear
envelope
√
Golgi
apparatus
X
Ribosomes
√
flagellum
Sometimes
present
The following table
compares some of
the features of
prokaryotic and
eukaryotic animal
cells
Complete the table using
ticks and crosses
Prokaryotic Eukaryotic
cells
cells
3.
DNA
present
Nuclear
envelope
present
Cell wall
present
Plasmids
present in
cytoplasm
Naked
DNA
present
√
√
The problem with plasmids
Homework – on paper
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Mitochondria and chloroplasts contain small
loops of DNA. They also contain ribosomes
that are the same size as prokaryotic
ribosomes.
Suggest an explanation for these features