Topic 1-Cell Biology Flashcards
What parts of an animal cell is there? What functions do they have?
Nucleus- contains genetic material that controls the activities of the cell. (Contains DNA)
Cytoplasm- gel like substance where most chemical reactions happen.
Cell membrane- holds the cell together and controls what goes in and out.
Mitochondria- where most reactions for aerobic respiration takes place.
Ribosomes- where proteins are made in the cell (protein synthesis).
What is only present in a plant cell? What is there function?
Cell wall- made of cellulose. Supports and strengthens the cell.
Permanent vacuole- contains cell sap (a weak solution of sugar and salts)
Chloroplasts- where photosynthesis occurs. Contain a green substance called chlorophyll which absorbs light needed for photosynthesis.
What do bacteria cells have?
Cytoplasm Cell membrane Cell wall A circular strand of free floating DNA Plasmids
Light microscopes Vs. Electron microscopes
Light microscopes- use light and lenses to form an image that’s magnified (allows us to see individual cells and large sub cellular structures).
Electron microscopes- use electrons and have a higher magnification, a higher resolution and allow us to see smaller things in more detail.
Magnification equation
Magnification= image size
—————-
actual size
What is differentiation?
Differentiation is the process by which a cell changes to become specialised to its job.
What are sperm cells specialised for and how?
Sperm cells are specialised for reproduction.
Long tail and streamlined head- to help it swim to the egg.
Lots of mitochondria- provides energy that the cell needs.
Carries enzymes- the help digest through the egg cell membrane.
What are nerve cells specialised for and how?
Nerve cells are specialised for rapid signalling.
Long- the cover more distance.
Branched connections- to form a network throughout the full body.
What are muscle cells specialised for and how?
Muscles cells are specialised for contraction.
Long- space to contract
Lots of mitochondria- generate energy needed for contracting.
What are root hair cells specialised for and how?
Root hair cells are specialised for absorbing water and minerals.
Grow long hairs- stick into the ground to give it a large surface area.
Big surface area- absorb water and minerals from the soil.
What are phloem and xylem cells specialised for and how?
They’re specialised for transporting substances.
Xylem cells are hollow
Phloem cells have very few sub cellular structures.
So stuff can flow through them.
What is the cell cycle?
Growth and DNA replication, mitosis
What are stem cells?
Stem cells are undifferentiated cells. They can divide to create more and they can differentiate into different types of cells, depending on what instructions they’re given.
Where can stem cells be found?
In human embryos
In adult bone marrow
In meristems of plants
How can stem cells be used to treat disease?
Stem cells can be extracted from the bone marrow of a healthy person to replace faulty blood cells in another patient.
Embryonic stem cells can replace faulty cells in sick people.
In what type of cloning could an embryo be made to have the same genetic material as a patient? Why’s this a benefit?
Therapeutic cloning, means the cells won’t be rejected by the body.
Why people may be against stem cell research?
Human embryos shouldn’t be used for experiments since each one is a potential human life.
Others think that curing existing patients is more important than the use of embryos.
Embryos used are usually unwanted ones from fertility clinics.
In some countries stem cell research is banned, it’s allowed in the UK but by using strict guidelines.
What is diffusion?
Diffusion is the spreading out of particles from an area of high concentration to an area of low concentration.
It happens in both gases and solutions
What effects the rate of diffusion?
The bigger the concentration gradient the faster the rate of diffusion.
The higher the temperature the faster the rate of diffusion as the particles have more energy.
What is osmosis?
Osmosis 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.
What is active transport?
When substances are absorbed against a concentration gradient (from a lower to higher concentration).
Examples of where active transport is used.
Root hair cells taking in minerals and water to get minerals from the soil into the plant cell.
Used in the stomach to get nutrients from the blood into the stomach.
How alveoli are adapted to maximise diffusion?
An large surface area
A moist lining for dissolving gases
Very thin walls
A good blood supply
What are the villi and how are they adapted?
Villi are found in the small intestine.
They increase surface area so digested food is absorbed a lot faster into the blood.
A single layer of surface cells
A very good blood supply- assist quick absorption
