Flashcards in Cell Biology Deck (32)
What are the differences between prokaryotic and eukaryotic cells?
Eukaryotic cells are more complex and contain genetic material in a nucleus. eg. animal and plant cells
Prokaryotic cells are smaller and their genetic material is not inside a nucleus. eg. bacteria
What subcelluar structures are in an animal cell?
What subcelluar structures are in a plant cell?
What is the function of the nucleus?
Contains genetic material that controls activities of the cell.
What is the function of mitochondria?
Where reactions for aerobic respiration occur.
What is the function of the cytoplasm?
Gel-like substance where most reactions take place.
What is the function of the cell membrane?
Holds cell together and controls what goes in and out.
What is the function of ribosomes?
Where proteins are made (proteinsynthesis)
What is the function of the cell wall?
Made of cellulose which supports the cell and strengthens it.
What is the function of chloroplasts?
Contain chlorophyll for photosynthesis.
What is the function of the vacuole?
Contains cell sap to keep the cell turgid.
What subcellular structures are in a bacteria cell?
No nucleus - DNA floats freely in the cytoplasm in a single loop (and sometimes with smaller rings called plasmids)
Compare light and electron microscopes
A microscope that uses light and lenses to create a magnified image.
A microscope that uses electrons to form an image but with a much higher magnification than a light microscope and with a higher resolution meaning smaller things can be seen in more detail. However it is also more expensive.
image size/real size
What is differentiation?
The process where a cell changes to become specialised for its function.
What is the function or a sperm cell and how is it specialised for this function?
It swims to get male DNA to the female DNA.
It has a long tail and streamlined head to help it swim.
It also has lots of mitochondria to provide lots of energy.
What is the function or a nerve cell and how is it specialised for this function?
To carry electrical signals from one part of the body to another.
They are long to cover more distance more distance and gave branches at the end to connect with other nerve cells to create a network.
What is the function or a muscle cell and how is it specialised for this function?
To contract quickly.
The cells are long so there's space to contract and contain lots of mitochondria for energy for contraction.
What is the function or a root hair cell and how is it specialised for this function?
They are cells on the surface of plant roots which grow into long roots into the soil. They have a large surface area for absorbing water and mineral ions.
What is the function of phloem and xylem cells and how is it specialised for this function?
They form phloem and xylem tubes that transport substances around plants. (Phloem tubes transport drink but xylem tubes transport food).
They are hollow and don't have many subcellular structures so substances can flow through them.
What is diffusion?
movement of particles from an area of high concentration to an area of low concentration
What affects the rate of diffusion?
Give an example of diffusion
oxygen diffusing through alveoli cell membrane into blood
(diffusion of glucose, amino acids and water through cell membranes)
What is osmosis?
movement of water molecules across a partially permeable membrane from an area of high concentration to an area of low concentration.
What is active transport?
Substances moving from an area of low concentration to an area of high concentration.
Why does active transport require a lot of energy?
it's moving against the concentration gradient
this energy is from respiration
How are alveoli adapted for diffusion?
large surface area
very thin walls
good blood supply
moist lining for dissolving gases
Why do multicellular organisms need exchange surfaces?
because they have a small surface area compared t volume
not enough substances can diffuse from their outside surface to supply their whole volume
exchange surfaces allow enough of the necessary substances to pass through
How are villi adapted to help digested food be absorbed into the blood?
single layer of outer cells
good blood supply to assist absorption