Transcript Unit 1 – Biology – Cells PowerPoint

Cell biology
Revision
B2 REVISION – CHAPTER 1 – Cells F
Eukaryotic and prokaryotic cells
Animal & Plant Cells
Where is the genetic material in a bacteria cell?
Structure
Purpose
Where is the genetic material in a plant cell?
Controls the cells
activities
Where is the genetic material in an animal cell?
What type of cell is shown to the right?
Plant/Animal/
Bacteria/all
Cytoplasm
What is a prokaryotic cell?
Both
What is a eukaryotic cell?
Mitochondria
Specialised Cells
Cells are specialised
to carry out a specific
function. The
structure gives a clue
to its function.
How is a root hair cell adapted
to absorb water and minerals?
Ribosomes
Protein synthesis
takes place
Plant
Contain
chlorophyll,
absorb light
energy to make
food
How is a sperm cell adapted to
swim to the egg?
Vacuole
If a cell has many chloroplasts what would its job be? Where would it be
found?
If a cell has many mitochondria it is making a lot of energy, which type of
cell might it be?
KEY WORDS:
Gland cells
Nucleus
Algal cell
Cellulose
Chloroplast
ASSESSMENT:
B2 REVISION – CHAPTER 1 – Cells H
Eukaryotic and prokaryotic cells
Animal & Plant Cells
Where is the genetic material in a bacteria cell?
Where is the genetic material in a plant and
animal cell?
Structure
Purpose
Plant/Animal/
Bacteria/all
Controls the cells
activities
Describe the structure of a bacteria cell (pictured
right)
Cytoplasm
Both
Specialised Cells
Say how each are specialised to carry out their function
function
Adaptations to carry out function
1.
sperm cells
2.
nerve cells
3.
muscle cells
4.
root hair cells
5.
xylem
6.
phloem
If a cell has many chloroplasts what would its job be? Where would it be
found?
If a cell has many mitochondria it is making a lot of energy, which type of
cell might it be?
Mitochondria
Ribosomes
Protein synthesis
takes place
Plant
Contain
chlorophyll,
absorb light
energy to make
food
Vacuole
ASSESSMENT:
KEY WORDS:
Gland cells
Nucleus
Algal cell
Cellulose
Chloroplast
Exam Questions
Practical: Growing Bacteria
Growing micro-organisms
Method
Questions
1. Why did you flame the loop?
2. Why did you allow the loop to cool?
3. Why is the Petri dish only opened a little?
4. Why do we incubate the bacteria at 25 C?
5. Why do we seal the Petri dish before incubation?
6. What do you call a bacteria that causes disease ?
Disinfectant =
Antibiotic =
Uncontaminated cultures of microorganisms are required for investigating the action of
disinfectants and antibiotics.
To prepare an uncontaminated culture:
• Petri dishes and agar must be ________ before use to kill unwanted microorganisms
• inoculating loops used to transfer microorganisms to the media must be sterilised by
passing them through a _________
• the lid of the Petri dish should be secured with adhesive tape to prevent
__________________ from the air contaminating the culture, and stored _________
_________to stop condensation drops falling onto the agar surface.
Missing words: flame, sterilised, microorganisms, upside down
Chromosomes
Learning Outcomes
R
A
G
Know that chromosomes are found
in the nucleus and carry genes.
Know that genes control
characteristics of the body.
Keywords
Cell
Nucleus
Chromosome
DNA
characteristics
Gene
Inherited
Gametes
Questions
Where in the cell is the genetic information
found?
What are the X shaped structures in the
nucleus?
What molecule are chromosomes made of?
What do chromosomes carry that control
characteristics of the body?
Use the key words to fill in the spaces…
Sexual reproduction
Information that results in plants and animals having
similar characteristics to their parents is carried by
________________, which are passed on in the
__________________________ from which the offspring
develop.
Male and female ________________ join. The
Different _______________ control the development of
different _______________________ of an organism.
mixture of genetic information from two parents
means that offspring are genetically different from
their parents.
Mitosis and the cell cycle H
Cell division & Growth
What cell division results in two
identical cells being produced
from an original cell?
Cell division in sexual
reproduction
By which process are gametes(sex
cells) produced?
What is the difference between
gametes and body cells?
In body cells, what are found in
pairs?
What is so special about stem cells?
How could stem cells be used to cure some disorders?
What are the gametes in plants called?
What are the gametes in animals
called?
What are unspecialised cells
called?
Stem Cells
More on Mitosis….
Cells divide in a series of stages called the cell ________. One of
these stages is __________ where the DNA, which has already
been copied, divides.
During the cell cycle the ______________ material is doubled
and then divided into two ______________ cells.
Before a cell can divide it needs to ________ and increase the
number of sub-cellular structures such as ribosomes and
____________. The DNA replicates to form two copies of each
chromosome. One set of ______________ is pulled to each end
of the cell and the nucleus divides. Finally the cytoplasm and cell
membranes divide to form two identical cells.
Cell division by mitosis is important in the growth, __________,
replacement of worn out ________ and _____________
Missing words reproduction, identical, mitosis, genetic, repair,
cycle, grow, chromosomes, cells, asexual, mitochondria,
KEY WORDS:
Meiosis
Ova
DNA fingerprint
ASSESSMENT:
Mitosis and the cell cycle H
Cell division & Growth
What cell division results in two
identical cells being produced
from an original cell?
Cell division in sexual
reproduction
By which process are gametes(sex
cells) produced?
What are the gametes in plants called?
Stem Cells
A stem cell is an _______________ cell of an organism which
is capable of giving rise to ______ other cells type.
Stem cells from human ________ and adult ______ marrow
can be cloned and made to differentiate into many different
types of human cells. Scientific research is trying to find ways
that stem cells can be used to cure many _____________.
Missing words
undifferentiated illnesses bone any embryos
What are the gametes in animals
called?
What is the difference between
gametes and body cells?
What are unspecialised cells
called?
In body cells, what are found in
pairs?
More on Mitosis….
Cells divide in a series of stages called the cell ________. One of
these stages is __________ where the DNA, which has already
been copied, divides.
During the cell cycle the ______________ material is doubled
and then divided into two ______________ cells.
Before a cell can divide it needs to ________ and increase the
number of sub-cellular structures such as ribosomes and
____________. The DNA replicates to form two copies of each
chromosome. One set of ______________ is pulled to each end
of the cell and the nucleus divides. Finally the cytoplasm and cell
membranes divide to form two identical cells.
Cell division by mitosis is important in the growth, __________,
replacement of worn out ________ and _____________
Missing words reproduction, identical, mitosis, genetic, repair,
cycle, grow, chromosomes, cells, asexual, mitochondria,
KEY WORDS:
Meiosis
Ova
DNA fingerprint
ASSESSMENT:
Stem Cells F and H
Keywords
Sexual reproduction
Asexual reproduction
Gametes
Cuttings
Tissue culture
Embryo transplant
Adult cell cloning
Clone
Plant Cloning
There are two methods of plant cloning…
Use the space provided to describe how each method works.
Cuttings
Tissue culture
___________________________________________________
____________________________________________________
Tick the statements that are true
____________________________________________________
____________________________________________________
 Only one parent is needed
____________________________________________________
__________________________
____________________________________________________
__________________________
Asexual reproduction
 Male and female gametes join
 No joining of gametes
 Offspring are genetically identical
 Offspring are clones of their parents
 Offspring are genetically different to their parents
Stem cells from meristems in plants can be used to
produce clones of plants quickly and economically.
• Rare species can be cloned to protect from
extinction.
• Large numbers of identical crop plants with special
features such as disease resistance.
In therapeutic cloning an embryo is produced with the
same genes as the patient. Stem cells from the embryo
are not rejected by the patient’s body so they may be
used for medical treatment.
Animal Cloning
Embryo transplants
An embryo is split up into several groups of cells and each group of cells is put into a
host mother.
Questions:
Is cow A genetically identical to cow B?
A
Is cow B genetically identical to cow C?
C
Adult cell cloning
Questions:
How do they get the egg cell to begin to divide into an embryo?
The lamb is genetically identical to which sheep, A, B or C?
Explain your answer.
B
Place the following units in order of size,
starting with the largest first
Microscopy
Match the unit with
the correct symbol
Micrometer
nm
Millimeter
cm
Centimeter
mm
Nanometer
µm
• ______________ = material placed
under a microscope.
• ______________ = the appearance
of material when viewed under the
microscope.
• The __________________ of an
object is how many times bigger the
image is when compared to the
object.
An electron microscope has much
higher ______________ and resolving
__________ than a light microscope.
This means that it can be used to study
cells in much _____________ detail.
This has enabled biologists to see and
understand many more sub-cellular
structures.
Missing words
Image, magnification, finer, object,
power, magnification
Use the triangle to complete the following equations:
Magnification =
Real/actual size =
Light microscope
Image size =
Electron
microscope
Can see images in
colour
Small field of view
Resolution
The resolution or resolving power of a microscope is the
minimum distance apart two objects can be in order for them
to appear as separate items.
The greater the resolution the greater the clarity.
The image produced is clearer and more precise.
Top tip – to help you
remember the equation
I AM
Slides are cheap
and easy to prepare
Can only view dead
objects
Magnification is
600x bigger than
the object.
OSMOSIS - definition
Osmosis is the movement of ___________ molecules from a _____________ solution to a ______________ solution
through a __________ permeable membrane.
Surrounding
solution
Where are
there more
water
molecules?
Does water
enter or leave
the cell.
Weak salt concentration
Pure water
water
Strong salt
concentration
concentrated
Partially
Dilue
2
Diffusion and definitions..
1.
. Substances may move into and out of cells across the cell
Complete the equation for respiration
Glucose + ___________
water + ___________ _________ + energy
What gas is needed for respiration?
Where does respiration occur?
What is the useful product of respiration?
What is the waste product of respiration?
How do these gases enter and leave the cell?
4.
In multicellular organisms the
smaller surface area to volume ratio
means surfaces and organ systems
are specialised for exchanging
materials. This is to allow sufficient
molecules to be transported into and
out of cells for the organism’s needs.
The effectiveness of an exchange
surface is increased by 4 things:
1.
2.
3.
4.
3.
Surface area to volume
ratios..
Single cells have a _________ surface area to
volume ratio. This means their surface is
large enough to be able to exchange
essential substances.
Multicellular organisms have a ___________
surface area to volume ratio. This means
their surface is not large enough to be able
to exchange essential substances. They
overcome tis by having organs specialised for
exchange. E.g. humans have ________ and
the ___________ ______________.
membranes via diffusion.
Diffusion is the ____________ of the particles of any substance
in ______________, or particles of a gas, resulting in a net
movement from an area of ___________ concentration to an
area of _____________ concentration ( __________ a
concentration gradient).
Some of the substances transported in and out of cells by
diffusion are _____________ and ____________ ________in
gas exchange, and of the waste
product _______ from cells into the blood plasma for excretion
in the kidney.
3 Factors which affect the rate of diffusion are:
1.
2.
3.
Missing words
Oxygen, solution, spreading, lower, carbon dioxide, higher,
down, urea
Examples of specialised exchange surfaces
Fish use gills for gas exchange.
Gills allow oxygen to enter the blood and carbon dioxide to leave.
1. Gills have numerous folds and fine gill filaments that give
them a very large surface area.
2. The folds are kept supported and moist by the water that is
continually pumped through the mouth and over the gills, so
water is constantly refreshed
3. The walls are thin.
4. The gills have a very good blood supply
5. The oxygenated blood is pumped away to
maintain a concentration gradient..
Humans have the small intestine to absorb small
soluble food (such as glucose, amino acids,
fatty acids and glycerol)
The small intestine has villi….
1.
The villi INCREASE THE OVERALL SURFACE AREA of
the small intestine, thus increasing the volume of
substances which can be absorbed by diffusion.
2.
The villi have a very GOOD BLOOD SUPPLY as each
contains a capillary, which leads to the main blood supply,
so when substances diffuse, they can go straight to the
bloodstream.
3.
Villi have very thin walls to allow
faster diffusion.
4. Villi are covered in cells that have
thousands and thousands of MICROVILLI.
These are exactly the same as the villi,
except a lot smaller. They further
increase the surface area.
Humans have lungs for gaseous exchange
Lungs allow oxygen to enter the blood and carbon dioxide to
leave. Lungs have numerous alveoli.
Alveoli
1. Are very thin – only one cell thick.
2. Have a very good blood supply
3. Are numerous and so create a very large surface area
4. Are ventilated so a concentration gradient is maintained.
Plants have leaves for gaseous exchange.
This is so oxygen and carbon dioxide can be exchanged for
photosynthesis and respiration.
During the day photosynthesis needs carbon dioxide to enter
the leaves and oxygen to leave.
Leaves
1. Are flattened to increase the surface area so more gases
can enter and leave (and more sunlight can be absorbed.
2. Are thin so there is a shorter distance for the gases to
diffuse in and out.
3. Have numerous stomata. These are holes mainly on the
underside of the leaves. They can open (usually in daylight)
to allow gases to enter and leave.
Create a revision table using the previous slide..
Organism
Exchange
surface
Substances that
are exchanged
How the surface is adapted for
exchange
Active Transport
Describe active transport in the root hair cell:
Describe the effects of osmosis in animal
cells:
Give the definition of active transport:
How is it different to diffusion:
Describe the how glucose is absorbed in the gut, place
the sentencess in the correct order
The molecules are then released into the cell
This increases the concentration inside the cell
A carrier protein is used to transport molecules
across the cell membrane
The concentration of glucose is higher inside the
cell than outside
Molecules need to be taken into the cell against
the concentration gradient
Active transport occurs when glucose is being
moved from a low concentration to a high
concentration
Energy is required to make the carrier protein
work. This energy comes from respiration
How is the root hair cell adapted for active
transport?
Active transport moves substances
from a more ___________ solution
to a more ______________ solution
(against a concentration gradient).
This requires _____________ from
___________.
Active transport allows
____________ ions to be absorbed
into plant root hairs from very dilute
solutions in the soil. Plants require
ions for healthy growth.
It also allows ___________
molecules to be absorbed from
____________ concentrations in the
gut into the blood which has a
__________ sugar concentration.
Sugar molecules are used for cell
respiration.
Missing words: lower, respiration,
dilute, mineral, energy,
concentrated, sugar higher.
Describe the effects of osmosis in plant
cells:
Which type of solution would an animal cell
burst in?
Why wouldn’t a plant cell burst if also
placed in this solution?
What would happen if root hair cells
absorbed mineral ions by diffusion?
What would happen if intestinal cells
absorbed glucose by diffusion?
Comparing the 3 modes of transport – rearrange the mixed up table below
Active transport
Osmosis
Diffusion
Does it require energy?
No
Yes
No
Does it require a membrane?
yes
yes
No
An example…
Does it go down a
concentration gradient?
Carbon dioxide diffuses into a
Absorption of glucose in the
leaf through stomata for
small intestine and mineral ions
photosynthesis
by root hair cells
Oxygen diffuses from the alveoli
to the blood.
Substances move along a
concentration gradient
Substances move against the
concentration gradient
Absorption of water by root
hair cells
Reabsorption of water in the
kidneys
Water moves along its
concentration gradient