Flashcards in Topic 1- Cell Biology Deck (53):
What is the difference between a prokaryotic cell and a eukaryotic cell?
Prokaryotic cells are smaller and simpler and is a single cell e.g. bacteria
Eukaryotic cells are complex e.g. animal and plant cells
Definition of turgid
Swollen or congested
Definition of flaccid
Limp or inelastic through lack of water
One adaptation of guard cells
Thin outer walls and thickened inner walls make the opening and closing work
3 adaptations of Red Blood Cells
Concave shape- big SA to absorb oxygen
Packed with haemoglobin (absorbs oxygen)
No nucleus, more space for haemoglobin
Where are there enzymes in a sperm cell and why?
In their heads to digest through the egg cell membrane
Function of epithelial tissue
Covers some part of the body e.g inside gut
Function of glandular tissue in the stomach
Makes digestive juice to digest food
Name of the small rings in bacteria
Formula to work out the magnification
Magnication = image size
Differences between light and electron microscopes
Light microscopes use light, to see cells and sub cellular structures e.g nuclei
Electron microscopes use electron and have higher magnification and resolution to see finer things e.g. ribosomes
Why might you add iodine solution when preparing a slide
It is a stain used to highlight objects by adding colour
What might obstruct your view when looking in your slide
Air bubbles under the cover slip
What does the course adjustment knob do?
Moves the stage
What is the purpose of the fine adjustment knob?
To focus until you get a clear image
What 8 things should you remember when you draw your observation?
Sharp pencil, use half the space, unbroken lines, no colour, drawn in proportion, title, magnification, label
What does a culture medium contain
Carbohydrates, minerals,proteins and vitamins
Why might temperatures not be kept at above 25°C?
Because harmful pathogens are more likely to grow above this temperature.
What could an inoculating loop be used for?
To transfer micro organisms to the culture medium
What is the inhibition zone?
Where no bacteria grows
What 4 things should you do to have uncontaminated cultures?
Petri dish and culture medium high temperature- kill unwanted
Inoculating loop passed through fire
Tape on lid lightly- stop air microbes
Store upside down, stop condensation drops falling
Formula to calculate area of inhibition zone
Definition of differentiation
The process by which a cell changes to become specialised for its job.
What are stem cells
They are undifferentiated cells. They can differentiate depending on the instructions they are given.
Difference between stem cells in embryos and adults
Embryonic stem cells can turn into any type of cell, whereas in adults, it's only found in certain places (e.g. Bone marrow). In adults they can only turn into certain ones.
2 examples of uses of embryonic stem cells
Insulin producing for diabetics
Nerve cells for paralysed people
What is therapeutic cloning?
When an embryo is made to have same genes as patient so stem cells won't be rejected by patient's body.
2 disadvantages of stem cell research
Could be contaminated when grown in lab and could be passed on.
Each embryo is potential human life and shouldn't be used for experiments.
2 advantages of stem cell research
Curing existing suffering patients is more important than rights of embryos
Embryos used normally are unwanted ones from fertility clinics that would be destroyed anyways.
Where are stem cells found in plants?
In the meristem (where growth occurs)
3 advantages of stem cell research in plants
Can be used to produce clones of whole plants quick and cheap
Can be used to grow more plants of rare species to prevent extinction
Can be used to grow plants with desired feature for farmers
Definition of diffusion
Diffusion is the spreading out of particles from an area of higher concentration to an area of lower concentration.
How does the concentration gradient and diffusion rate link?
The bigger the concentration gradient (difference in concentration) the faster the diffusion rate.
What is diffusion like in the cell membrane?
Only very small dissolved substances move in and out through diffusion. (Oxygen, glucose, amino acids & water)
Definition of osmosis
It is the movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration.
An experiment to show osmosis?
Get two identical cylinders and fill one with pure water and one with different concentrated sugar solution and put a potato cylinder in each one, measure mass and leave for 24 hours. Take them out and dry them and measure mass.
How do the adaptations of root hair cells help with the job?
Millions of hairs- large SA for water ad mineral absorption important for growth.
Why do root hair cells use active transport?
Because the concentration of mineral is usually higher in the cell than the soil
What is needed for active transport?
Energy from respiration
What is the purpose of active transport in the blood?
It means glucose can be taken into the bloodstream when it's concentration in the blood is already higher than in the gut. It is then transported to cells (respiration)
Surface area to volume ratio
The larger an organism, the smaller its SA
Which two body parts are adapted the most effectively for diffusion?
Lungs and inside the small intestines
4 adaptations of alveoli
Enormous surface area
Moist lining for dissolving gases
Very thin walls
Good blood supply
What is the purpose of villi in the small intestine?
So that digested food is absorbed much more quickly into blood
How is water vapour lost from a leaf?
All over the leaf surface and mostly through the stomata
What is the purpose of guard cells?
They control the size of stomata. They close the stomata if plant is losing water faster than it being replaced by roots.
Without it, the plant would wilt.
What are involved in diffusion in a leaf
Oxygen and water vapour diffuse out and Carbon Dioxide diffuse in.
What is the gas exchange surface in fish?
Describe diffusion in fish.
Water enters through mouth and out through gills
As it happens, oxygen diffuses in from water to blood in gills and CO2 diffuses from blood into water.
What is a gill made of?
Gill filaments which increase SA and covered in lamellae which also increase SA.
Adaptations of lamellae
Lots of capillaries- speed up diffusion
Thin surface- minimise distance that gases have to diffuse
Blood flow in 1D, water flow in another D- maintains large CG between water and blood
Definition of lysis
When an animal cell takes in too much water and bursts