B1- Cell biology Flashcards
What is a eukaryotic cell?
Complex cells that include all animal plant cells
What is a prokaryotic cell?
Smaller and simpler cells such as bacteria
What are eukaryotes?
Organisms made up of eukaryotic cells
What are prokaryotes?
A single celled organism made up of one prokaryotic cell
What is the name for different parts of a cell?
Sub cellular structures
What are the sub cellular structures of an animal cell?
Nucleus
Mitochondria
Cytoplasm
Cell membrane
Ribosomes
What is a nucleus?
Contains genetic material that controls cell activity
What are mitochondria?
Where most of the reactions for aerobic respiration takes place
What is cytoplasm?
A gel like substance that contains enzymes which control the chemical reactions that take place there
What is a cell membrane?
Holds the cell together and controls what goes in and out
What are ribosomes?
The site of protein synthesis
What extra sub cellular structures do plant cells have?
Cell wall
Vacuole
Chloroplasts
What is a cell wall?
Made of cellulose and supports and strengthens the cell
What is a vacuole?
Contains cell sap that is a weak solution made up of sugar and salts
What are chloroplasts?
They contains chlorophyll which absorbs light and are where photosynthesis occurs
What are the sub cellular structures of a bacterial cell?
Cell membrane
Cell wall
Circular strand of DNA
Plasmid
Cytoplasm
What do bacterial cells not have?
A nucleus
Chloroplasts
Mitochondria
What do bacterial cells have instead of a nucleus?
A single circular strand of DNA that floats freely in the cytoplasm
What is a plasmid?
One or more small rings of DNA
What is the formula for magnification?
Magnification = image size / real size
What are the parts of a light microscope?
Eyepiece
Coarse adjustment knob
Fine adjustment knob
Light
Stage
High power objective lens
Low power objective lens
What do you need to prepare a slide?
Slide
Water drop mixed with iodine
Iodine stained specimen
Cover slip
What is cell differentiation?
The process by which a cell changed to become specialised for its job
What are undifferentiated cells called?
Stem cells
What are five examples of specialised cells?
Sperm cells
Nerve cells
Muscle cells
Root hair cells
Phloem and Xylem
How are sperm cells specialised?
They have a long tail and streamlined head to help it swim to the egg, lots of mitochondria to provide the energy needed, it carries enzymes in its head to digest through the egg cell membrane to get male DNA to the female DNA
How are nerve cells specialised?
They are long to cover more distance and have branched connections at their ends to connect to other nerve cells and fora network throughout the body so they can carry rapid electrical signals
How are muscle cells specialised?
They are long so they have space to contract and contain lots of mitochondria to generate the energy needed for rapid contraction
How are root hair cells specialised?
They are on the surface of plant roots, they grow into long hairs to stick out into the soil and absorb water and minerals, this gives the plant a big surface area for absorbing
How are phloem and Xylem cells specialised?
They form phloem and xylem tubes to transport substances around the plant, to form the tubes the cells are long and joined end to end, xylem cells are hollow in the centre and phloem have few sub cellular structure so things can flow through them
What are embryonic stem cells?
They are found in early human embryos and have the potential to turn into any type of cell
Why do scientist want to grow stem cells in labs?
To produce clones that are made to differentiate into specialised cells to use in medicine and research
How can embryonic stem cells cure disease
They can be used to replace faulty cells in sick people, become insulin producing cells for people with diabetes, nerve cells for those paralysed and so on
Why are people against embryonic stem cell research and some aren’t?
Some are against it because they are potential human life whilst others argue the already living sick person is more important
How can stem cells produce identical plants?
Stem cells are found in the plants meristems and are used to produce clones of whole plants quickly and cheaply, this is useful for endangered species, farmers and plant disease resistance
Where are adult stem cells found?
Bone marrow
How can adult stem cells cure disease?
They are transferred from the bone marrow of a healthy person to fix faulty blood cells of a sick person
Is stem cell research allowed in the UK?
Yes if it follows strict guidelines
What is diffusion?
The spreading out of particles from an area of higher concentration to a area of lower concentration
What is osmosis?
The movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration
What is a partially permeable membrane?
A membrane with very small holes so only small molecules like water can pass through it
What is active transport?
Substances absorbed against a concentration gradient such as from an area of lower to higher concentration
What is an example of a cell that uses active transport?
Root hair cells take in minerals using active transport
How is active transport used in the gut?
When there is a lower concentration of nutrients in the gut but a higher concentration of nutrients in the blood it allows nutrients to be taken in when the concentration gradient is the wrong way
How are exchanged surfaces adapted in multicellular organisms to maximise effectiveness?
They have a thin membrane for short diffusion distance, they have a large surface area so more diffusion can take place, in animals they have a lot of blood vessels to get things in and out of the blood quickly and gas exchange in animals are often ventilated
How are alveoli adapted for gas exchange in the lungs?
They have a huge surface area, a moist lining for dissolving gases, very thin walls and a good blood supply
How is the small intestine adapted for substance exchange?
The inside is covered in millions of villi that increase surface area to absorb digested food quicker, they have a single layer of surface cells, a good blood supply and they are covered in micro villi
How are leaves adapted to let gas diffuse in and out?
In book
How are gills adapted for gas exchange?
They are made of lots of thin plates called gill filaments that give a big surface area for gas exchange, the filaments are covered in lamellae to further increase surface area
How are lamellae adapted in gills for gas exchange?
They have lots of blood capillaries to speed up diffusion, a thin surface layer of cells to minimise diffusion distance and blood and water flow in opposite directions to maintain a large concentration gradient between the blood and the water
