Cell biology Flashcards
What are eukaryotic cells?
Plant and animal cells that have genetic material enclosed inside a nucleus
What are prokaryotic cells?
Bacterial cells that are smaller than eukaryotic cells and have genetic material stored inside DNA loops
What structures are found in most animal cells?
A nucleus, cytoplasm, cell membrane, mitochondria and ribosomes
What structures are found in most plant cells?
A nucleus, cytoplasm, cell membrane, mitochondria, ribosomes, chloroplasts, a sap-filled vacuole and a cell wall
What are some examples of specialised cells?
Sperm, nerve and muscle cells in animals and root hair cells, xylem and phloem cells in plants
How does cell differentiation differ between plant and animal cells?
Whilst most animal cells differentiate at an early stage, many plant cells have the ability to differentiate throughout their life
How does an electron microscope differ from a light microscope?
An electron microscope has a far higher magnification and level of detail than a light microscope, allowing biologists to understand many more sub-cellular structures
What is the equation for magnification?
Magnification = size of image/size of object
What happens before a cell divides?
It increases the number of sub-cellular structures such as ribosomes and mitochondria
Does mitosis produce identical cells?
Yes
What is mitosis used for in organisms?
Growth and repair
What is a stem cell?
A cell capable of giving rise to many cells of the same type, and can differentiate to form other forms of cells
Where does stem cell grow in the human body?
Adult bone marrow
Why are plants cloned?
To preserve rare species’ and to produce plants with special features such as disease resistance
Which factors affect the rate of diffusion?
Concentration gradient, temperature and the membrane surface area
How is the effectiveness of an exchange surface increased?
A large surface area, a thin membrane for a short diffusion path, an efficient blood supply and, for gas exchange, being ventilated
What is osmosis?
The diffusion of water from a dilute to concentrated solution through a partially permeable membrane
What is active transport?
The movement of substances from a dilute soluction to a more concentrated soluction, against the concentration gradient
Which process does active transport use energy from?
Respiration
How is active transport used in plants?
It allows mineral ions to be absorbed into root hairs from dilute solutions in the soil; it requires plant ions for healthy growth
