B2.1: Supplying The Cell Flashcards
What is diffusion?
The net movement of particles from an area of high concentration to an area of low concentration along a concentration gradient
How does distance affect the rate of diffusion?
The shorter the distance, the faster the diffusion.
This is because particles need to move a shorter distance to reach equilibrium
How does temperature affect diffusion?
The higher temp, the faster diffusion
What is osmosis?
The diffusion of water from an area of high water potential to an area of low water potential through a partially permeable membrane
What is a hypertonic solution?
When the solute concentration is greater outside of the cell, the cell will shrink and water will go out
What is a hypotonic solution?
When the solute concentration is lower outside the cell, the cell will swell and gain water
What is a solute
A substance dissolved
What is a solvent
A substance that does the dissolving
A hypertonic solution can cause a plant cell to plasmolyse. What does that mean?
It loses water through osmosis
What does turgid mean?
When cell walls become rigid due to high water content
What is an isotonic solution?
Solute concentration is the same inside and outside
What is lysis
Bursting of the cell after hypotonic solution
What is active transport?
The movement of molecules against a concentration gradient using energy
- involves transport of solutes
- needs semi-permeable membrane
Which processes use active transport?
How minerals get into root hair cells
What is a specialised cell?
A cell which has adapted unique features to perform its functions
What is differentiation?
Process in which cells become specialised in structure and function
How is a sperm cell specialised?
The flagellum helps to move towards the egg cell
Many mitochondria to provide energy
How are ciliated cells specialised?
It has tiny hairs called cilia, which sweep up mucus with trapped dust and a bacteria at the back of the throat
What is a stem cell?
An undifferentiated cell - a cell that has not yet become specialised
What are features of a stem cell?
- can replicate many times
- has the potential to become any type of cell
What are the 2 sources of stem cells?
Adult stem cells - bone marrow
Embroynic stem cells
Where are adult stem cells found?
Bone marrow
Long bones like the femur
What are the 3 types of stem cells found in the bone marrow?
- blood
- skin
- bone
Where are emrbyonic stem cells found?
In early human embryos (blastocyst)
What is the difference between embryonic and adult stem cells?
Embryonic stem cells can differentiate into more cell types than adult stem cells
Where are plant stem cells found?
Meristems, neart the tip of shoots and roots
What can meristems differentiate into?
Into any type of plant cell
What are some advantages of adult stem cells?
Costs 1000£
Adults give permission
Safe procedure
What are disadvantages of adult stem cells?
Can only develop into a few types of cells
High chance of rejection from patients immune system
Each cell divides every 4 hours
What are some advantages of embryonic stem cells?
Can develop into many cell types
Each cell divides every 30mins
Low chance of patient immune system rejection
What are some disadvantages of embryonic stem cells?
Costs 5000£ to collect a few cells
Ethical issues
More research needs to be done
What kind of cells does mitosis produce?
Identical cells - 2 daughter cells that have the same number of chromosomes as the parent cell: 46 chromosomes
What does mitosis aid with?
Growth
Repairing tissue
Replacing old or damaged cells
Where in the body does mitosis occur?
Skin
Muscle
Bone cells
NOT in reproductive cells
What type of variation is between the parent and daughter cells?
No variation
What are the advantages of mitosis?
Only needs 1 parent - quicker, faster
What is the order of mitosis?
- growth of the cell
- dna replication
- movement of chromosomes
What is stage 1 of mitosis?
Growth
Increase the number of sub cellular structures
What is stage 2 of mitosis?
DNA synthesis
DNA replicates to form 2 copies of each chromosome
What is stage 3 of mitosis?
Mitosis
One set of chromosome pulled to each end of cell and nucleus divides. Cytoplasm and cell membrane divide to form 2 identical cells to the parent cells
Does the size of the cells get smaller during mitosis?
Yes, but not too much
They still maintain an appropriate size
What is cell differentiation?
The process where cells become specialised
Why is cell differentiation important?
It allows organisms to develop specialised functions
When does differentiation occur in animals?
Mostly during embryo development
When does differentiation occur in plants?
Throughout their lifetime
What is the function of a nerve cell?
To carry electrical impulses
How is a nerve cell adapted?
Long branched connections for communication
What is the function of a sperm cell?
To fertilise an egg
How is a sperm cell adapted?
It has a tail for swimming and enzymes to penetrate the egg
What is the function of a muscle cell?
To contract and allow movement
What is the function of a root hair cell?
Absorbs water and minerals
How is a root hair cell adapted?
Large surface area due to hair like projections
What is the function of xylem?
Transports water and minerals
How is xylem adapted?
Hollow tubes strengthened with lignin
Wat is the function of phloem?
Transports sugars and nutrients
How is phloem adapted?
Sieve tubes. – specialised for transport and have no nuclei
Companion cells with mitochondria for energy
Does diffusion require energy?
NO
Its a passive process
What affects diffusion rate?
Temperature
Surface area
Concentration gradient
Diffusion distance
Where does osmosis occur in plants?
In root hair cells in order to absorb water
Does active transport require energy
Yes
From ATP
Where does active transport occur in plants?
In root hair cells to absorb minerals
What is mitosis?
Cell division producing identical cells to the parents
Why is mitosis important?
Asexual reproduction
Growth
Repair
What are the stages of the cell cycle?
Growth
DNA synthesis
Mitosis
What happens in the growth phase of the cell cycle?
Cell grows and makes more organelles
What happens in DNA synthesis of cell cycle?
DNA is replicated
What happens during mitsosis?
The nucleus divides forming 2 identical cells
What are stem cells?
Undifferentiated cells that can develop into different types
Where are embryonic stem cells found?
In early-stage embryos
What can embryonic stem cells become?
Any cell type
Where are adult stem cells found?
Tissues like the bone marrow
What can adult stem cells become?
Only certain cell types (like blood cells)
Where are plant stem cells found?
Meristems
How can stem cells be used in medicine?
To treat conditions like diabetes and paralysis
How can stem cells be used to treat disease?
stem cells replace cells damaged
How can plant stem cells be used?
To clone plants with desirable traits
Why is plant cloning useful?
It helps growing disease-resistant crops
What are ethical issues with embryonic stem cells?
Some believe using embryos is wrong
What is a medical risk of stem cell therapy?
Cells could be rejected or cause infection
What is active transport?
Movement of substances against a concentration gradient requiring ATP
What is the difference between embryonic and adult stem cells?
Embryonic stem cells are pluripotent (can become any cell type)
Adult stem cells are multipotent (limited differentiation)
