Cell Differentiation and Specialisation Flashcards
(17 cards)
What is ‘cell differentation’?
The process by which a cell changes, becoming more suited/specialised for a particular function. As cells change, they develop different subcellular structures.
When does differentation occur in organisms?
mention different types of cell, eg. animal cell etc
Most differentation occurs as an organism develops.
In most animal cells, the ability to differentiate is then lost at an early stage, after they become specialised. However, lots of plants don’t loose this ability.
List the adaptations of a root hair cell and how this helps it function.
Root hair cells are specialised structures that allow plants to absorb water and minerals from soil.
Their elongated structure/long projection precisely aid in increasing echange of nutrients between the soil and plant.
Contains lots of mitochondria for active transport between minerals outside plant and inside plant.
Increased surface area - increases rate of osmosis (water)
List the adaptations of a sperm cell and how this helps it function.
Function of a sperm cell is to fertilise the egg. Adaptations include:
* Tail to help it travel and fertilise egg
* Contains nucleus which contains genetic material
* streamlined head
* Mitochondria provide energy for their journey
* Acrosome contains enzymes in order for sperm to penetrate egg
Why does the root hair cell contain mitochondria?
- Respiration occurs in the mitochondria
- Mitochondria release energy used for active transport to transport mineral ions against a concentration gradient, from an area of low concentration to high concentration
List the adaptations of a muscle cell and how this helps it function.
The function of the muscle cell is to contract and move food along the gut, or to contract, enabling part of your body move.
The muscle cell contains many mitochondria to transfer energy for contraction
What is the function of the xylem?
The xylem cell transports water and minerals from the roots to the stem and leaves, by a process called transpiration.
What is the function of the phloem?
The phloem transports dissolved sugars both up and down the plant through a process called translocation
Compare the xylem and phloem tissues?
Both tissues are strong, but xylem is strengthened by material called lignin, phloem has rigid cell wall that withstands pressure
Xylem is made of dead cells, phloem is made of living cells
Xylem has unidirectional transportation of water, phloem has bidirectional transport of sugars
Xylem and phloem are both tubular
Xylem = transpiration, phloem = translocation
xylem transfers water + minerals, phloem transports glucose/ dissolved sugars
xylem has no end walls, phloem has walls called seive plates
What is an isotonic solution?
If two solutions have the same concentrations of water and solutes, there is no overall movement of water, causing the same volume of water to move in both directions (if separated by partially permeable membrane)
What is a hypertonic solution?
If one solution has higher concentration of solute than another, one with higher solution is hypertonic - because it has a higher solute concentration and lower water concentration
What is a hypotonic solution?
A solution with a lower concetration of solute than another.
What do hypertonic and hypotonic solutions do to red blood cells?
Hypertonic solution - red blood cell would shrivel up because water from inside blood cell would move into solution by osmosis.
Hypotonic solution - red blood cell would swell up because water from outside the red blood cell would move into it
What are stomata?
Tiny pores found on leaves that control gas exchange and water loss - allow CO2 in and O2 and water vapour out.
What happens when the stomata fill or loose water?
Stomata are surrounded by guard cells. Stomata open when cells fill with water, become turgid. They close when cells lose water, becoming flaccid.
What are the main factors affecting transpiration rate?
Include examples for all
Light intensity - greater light intensity, greater rate of transpiration. Eg. When dark, photosynthesis cannot take place, and stomata close meaning little water can diffuse out of leaves.
Temperature - greater temperature, greater rate of transpiration. Eg. Water particles have more energy when it’s warm, so they evapporate and diffuse out stomata at faster rate
Air flow - greater air flow, greater rate of transpiration. When air flow is fast, water vapour is moved away from plant quickly so more water can evaporate. Also creates high concentration gradient for diffusion.
Humidity - lower humidity, greater rate of transpiration. Eg. when air is dry, water would move by osmosis from inside plant to outside plant.
When do stomata become smaller?
Pores in stomata become smaller if a plant needs to reduce amount of water being lost by transpiration
