Cell Biology Flashcards
Before the bacterial cell can divide, what 2 main things must it do?
Grow and Replicate genetic material
Are the cells created by mitosis genetically identical to each other, or genetically different?
genetically identical
Can paralysis be treated with adult stem cells and why?
no, as adult stem cells cannot differentiate into nerve cells
Give 2 examples of eukaryotic cells.
animal and plant
Give 2 organelles present in plant cells but not in animal cells.
Permanent vacuole, chlorplast
Give 4 organelles present in both animal and plant cells.
cytoplasm, nucleus, ribosomes, mitochondria, cell membrane
Give an example of a prokaryotic cell
Bacteria
Given the right conditions, what is the fastest bacteria can divide?
once every 20 minutes
How do scientists use stem cells to treat some conditions?
1) They extract embryonic stem cells from early embryos
2) They grow them in a laboratory
3) They stimulate them to differentiate into whatever specialised cell is needed
4) They give them to the patient to replace the faulty cells
How does binary fission work?
1) The cell grows
2) Genetic Material is duplicated
3) the 2 longs strands of DNA each go 2 one side of the cell, and the plasmids are arranged randomly
4) A cell wall is made in the middle of the cell to divide it
5) The cell pulls apart to form 2 new cells
How many PAIRS of chromosomes do humans have?
23 pairs
Instead of a nucleus, what 2 organeles contain the DNA in a bacterium?
The circular strand of DNA and plasmids
Is binary fission cell division or reproduction and why?
It is both because bacteria are unicellular organisms
What 3 conditions could be treated by stem cells?
Type 1 diabetes
Paralysis
Sickle Cell Anaemia
What 3 organelles do bacteria not have?
Mitochondria, Nucleus, chlorophyll
What are 2 disadvantages of electron microscopes?
Very expensive, hard to use
What are 2 main features of stem cells?
They can divide by mitosis, and they can differentiate into specialised cells.
What are 3 advantages of light microscopes?
Easy to use, cheap and portable
What are 3 types of stem cells?
Plant, Adult, Embryonic
What are cell fibres?
Fibres that attach to chromosomes to split them
What are chromosomes?
coiled up packets of DNA
What are the 2 main drawbacks of using stem cells to treat conditions?
1) Requires embryonic stem cells, which are limited in suppl and have ethical issues
2) The patients body may reject the stem cells as they are foreign
What are the 2 main risks of using stem cells in medicine?
Virus transmission and tumor development
What are the 3 main stages of the cell cycle?
Growth, DNA replication + mitosis, division
What are the poles of a cell?
The 2 sides that chromosomes are split to
What can adult stem cells found in the bone marrow differentiate into?
Blood cells
What can plant stem cells differentiate into?
Any cell
What condition could be treated using adult stem cells?
Sickle cell anaemia
What do all eukaryotic organisms require a continous supply of new cells for?
Growth, development, and repair
What does a vacuole contain?
cell sap, which is a mixture of sugars, salts and water
What does unicellular mean?
single celled organism
What genes does the circular strand of DNA contain in a bacterium?
The genes they need to survive and reproduce
What happens in ribosomes?
protein synthesis
What happens in the 2nd stage of the cell cycle (DNA replication)?
The DNA is duplicated by mitosis so the daughter cells can have identical DNA
What happens in the first step of the cell cycle (Growth)?
The cell increases the number of sub-cellular structures
What happens in the last stage of the cell cycle (division)?
The cell membrane and cytoplasm pull apart, to create 2 daughter cells. Each daughter cell has all 46 identical chromosomes
What happens to the chromosomes when the cell is dividing?
Each chromosome is duplicated and the duplicate stays attached to the original
What happens to the DNA when the cell is getting ready to divide?
The DNA condenses into chromosomes
What happens to the duplicated chromosomes when the cell is dividing?
The duplicated chromosmes line up in the middle of the cell, then cell fibres from both sides attach to their respective side of the X shaped chromosome. The fibres pull apart the attached chromosomes so that the duplicated ones are all onn one side and the originals on the other.
What is a cell wall made of?
cellulose
what is a cell?
The smallest unit of life that can replicate independantly
What is a disadvantage of light microscopes?
Thay dont have a very high magnification or resolution
What is a flagellum?
It is a small tail-like organelle that rotates to propel the bacterium forward, however not all bacteria have one
What is an advantage to the electron miscroscope?
It has a much higher resolution and magnification
What is binary fission?
The process by which prokaryotic organsims divide and reproduce
What is differentiation?
The process in which a stem cell becomes a specialised cell
What is magnification?
How many times larger the image is than the object
What is resolution?
The shortest distance between 2 points on an object, that can still be distinguished as separate.
What is the approx. size of an atom?
0.1-0.2 nm
What is the image in microscopy?
the image we see when we look down the microscope
What is the lens that you put your eye to?
Eyepiece lens
What is the magnification equation?
magnification = image size / object size
What is the object in microscopy?
the real object or sample you are looking at.
What makes plant’s leaves green?
Chlorophyll
What process do stem cells use to divide?
Mitosis
What shape do the duplicate chromosomes form when they are attached?
an X shape
What two knobs are there in a light microscope?
Coarse focusing and fine focusing
what type of cell is a bacterium?
prokaryotic
What type of cell is a fungus?
eukaryotic
Where can adult stem cells be found?
In the bone marrow
Where can you find the objective lenses?
above the stage, below the main body
Where do you find plant stem cells?
Meristem tissue of a plant
Where is the meristem tissue found?
THe tips of the roots and shoots
Which cells can an embryonic stem cell differentiate into?
Any type of specialised cell
What is the definition of diffusion (memorise)?
the net movement of particles from an area of higher concentration to an area of lower concentration
Does diffusion require energy?
no, diffusion is a passive process
what are 3 factors that effect the rate of diffusion?
larger concentration gradient = higher rate of diffusion
higher temperature = higher rate of diffusion
larger the surface area = higher the rate of diffusion
Which 3 molecules are able to diffuse in and out of cells?
amino acids, glucose and water
Why does a higher temperature increase the rate of diffusion?
when the temperature is higher the particles have more energy and move around more, allowing them to diffuse faster
What is osmosis?
The diffusion of water across a partially permeable membrane from high water concentration to low concentration
What is water concentration?
The amount of water compared to other particles dissolved within the water
What would happen to red blood cells if they were placed in pure water?
They would gain water and swell
Does active transport require energy?
yes, it is an active process
What is active transport?
movement of molecules against their concentration gradient, which requires energy
Where does the energy for active transport come from?
cellular respiration
Where is active transport used?
in the root hair cells of plants in order to take in water and minerals from the soil
True or false? Active transport can only take place across a membrane.
True
How do our lungs increase the surface area?
through the alveoli
How does our small intestine increase the surface area?
through villi
What are the 2 main exchange surfaces in a human?
alveoli and villi
What are the 2 main exchange surfaces in plants?
root hair cells and leaves
What are common features between specialised exchange surfaces?
large surface area, the surfaces are usually very thin, the surfaces are permeable to the substances they need to exchange
