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The genetic material in a plant and animal cell is found in the
Nucleus
Plant and animal cells both have
A nucleus, a cell membrane and cytoplasm
Bacterial cells are also known as
Prokaryotic cells
Plant and animal cells are also known as
Eukaryotic cells
What is the size of bacterial cells compared to eukaryotic cells
Bacterial cells are smalle
Bacterial cells have small rings of DNA called
Plasmids
What is different about the genetic material in bacterial cells compared to animal cells?
It is not enclosed in a nucleus
What material is the cell wall of plant and algal cells made from?
Cellulose
What parts of a plant cell are not found in animal cells
Chloroplasts Permanent vacuole
What is found in the permanent vacuole of a plant cell
Cell sap
What is the function of the nucleus?
Controls the activities of the cell. It is where the genetic material is found
What is the function of the cytoplasm?
A liquid gel where most chemical reactions take place
What is the function of the cell membrane?
Controls the passage of substances into and out of the cell
What is the function of the mitochondria?
Where aerobic respiration takes place, releasing energy for the cell
What is the function of the ribosomes?
Where protein synthesis takes place
What is the function of the chloroplasts?
Contain chlorophyll Chlorophyll absorbs light so the plant can make food by photosynthesis
What is the function of the permanent vacuole?
Important for keeping the cells rigid to support the plant
What is the function of the cell wall?
Made of cellulose which helps strengthen the cell and provides support
What is the function of the plasmids?
Where some of the genetic material is found in bacterial cells
What type of microscope would you use to observer ribosomes?
Electron microscope
Give a specialisation of a sperm cell
A large nucleus containing genetic information A long tail to assist with movement The mid-section is full of mitochondria to transfer energy for movement
Give a specialisation of a nerve cell
A long axon to carry information over long distances Numerous dendrites to pass information to neighbouring nerve cells
Give a specialisation of a muscle cell
Contain mitochondria to transfer the energy needed for contracting
Give a specialisation of a root hair cell
Root Hair increases the surface area for efficient water uptake Large permanent vacuole to maintain water potential
Give a specialisation of a xylem cell
Lignin builds up in the cell wall increasing the strength of the xylem allowing them to withstand the water pressure The Xylem cells die forming long hollow tubes that allow water move with little resistance up the plant
Give a specialisation of a phloem cell
Cell walls between neighbouring cells breaks down to form sieve plates that allow water to move freely Phloem cells have relatively few organelles but are kept alive by companion cells
When do most types of animal cells differentiate?
At an early stage
What is different about when most type of plant and animal cells differentiate?
Many types of plant cells retain the ability to differentiate throughout life
In mature animals what is cell division for?
Repair and Replacement
What do we call a cell that has differentiated?
A specialised cell
What is the definition for magnification?
How many times bigger an object appears
What is the definition for resolution?
The ability to distinguish between two separate points
Which has a higher resolving power? An electron or light microscope
Electron microscope
Why are electron microscopes more useful
They can study cells in much finer detail and see more sub-cellular structures
What formula links magnification, size of image and size of real object
Magnification = Size of image/Size of real object
Which type of microscope has a higher magnification
Electron microscope
What does the nucleus of a cell contain?
Genetic Information / Chromosomes
What are chromosomes made from?
DNA molecules
In body cells how are the chromosomes normally found?
In pairs
Cells divide in a series of stages. What is this called?
The cell cycle
What happens in the first stage of the cell cycle?
The number of sub-cellular structures increases The DNA replicates The cell increases in mass
What happens in the second stage of the cell cycle?
Mitosis occurs The chromosomes are pulled to each end of the cell The nucleus divides
What happens in the third stage of the cell cycle?
The cytoplasm and cell membrane divide to form two identical cells
What is mitosis important for?
Growth and development
How many cells are produced in mitosis?
2
What are the cells produced in mitosis like?
Identical
What is a stem cell?
An undifferentiated cell of an organism which can become other types of cell
Where are the two main sources of human stem cells?
Embryos Adult Bone Marrow
In which type of plant tissue do you find cells that can differentiate into any type of plant cell?
Meristem
What conditions could treatment with stem cells help?
Diabetes and Paralysis
What is produced in therapeutic cloning?
An embryo with the same genes as the patient
What is the advantage of using stem cells from embryos for medical treatment?
They will not be rejected from the patient
What are the risks of using stem cells?
The transfer of viral infections
What can the stem cells from meristems in plants be used for?
To produce clones of plants quickly and economically
How can rare species of plants benefit from meristem tissue?
Rare species can be cloned to protect from extinction
How can crop plants benefit from meristem tissue?
Crop plants with special features such as disease resistance can be cloned to produce large numbers of identical plants for farmers
What is the definition of diffusion?
The movement of molecules down a concentration gradient from a higher to a lower concentration
What substances may be transported into animal cells?
Oxygen
What substance my be transported out of animal cells?
Carbon dioxide, Urea
Which factors affect the rate of diffusion?
The difference in concentration The temperature The surface area of the membrane
What is the surface area : volume ratio like in a single celled organism?
High
How are the small intestines adapted as exchange surfaces
Villi to increase the surface area
How are the lungs adapted as exchange surfaces?
Alveoli to increase the surface area Lots of capillaries for efficient exchange Thin walls to provide a short pathway
How are gills in fish adapted as exchange surfaces?
Excellent blood supply Large surface area
How are roots adapted as exchange surfaces?
Large surface area
What increases the effectiveness of an exchange surface?
Large surface area Thin membrane for short diffusion pathway Efficient blood supply (animals) Ventilated (Animals for gaseous exchange)
What moves via osmosis?
Water
What is the definition of osmosis?
The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane
What does osmosis require for it to occur?
Partially permeable membrane
What is the definition of active transport?
Active transport moves substances from a more dilute solution to a more concentrated solution (against a concentration gradient)
What does active transport require?
Energy from respiration
Where does active transport occur in plants?
Active transport occurs in the plant root hairs, allowing mineral ions to be absorbed from very dilute solutions in the soil
Why do plants require ions?
Healthy growth
Where does active transport take place in humans?
It allows sugar molecules to be absorbed from low concentrations in the gut into the blood
Why do humans require sugar molecules?
Cellular respiration
Where does the energy in active transport come from?
Respiration
What do we call the process in which bacteria reproduce?
Binary fission
How often will bacteria reproduce?
Once every 20 minutes
When will bacteria reproduce?
Enough nutrients and suitable temperature
Where can bacteria grow?
Nutrient broth or as colonies on an agar plate
At what temperature should cultures be incubated at?
25oC
What do we use to transfer microorganisms to the media?
Inoculating loops
How do you sterilise the inoculating loop?
Passing through a flame
How should the Petri dish be secured?
With adhesive tape on the side and stored upside down
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