Supplying the Cell B2.1 Flashcards
What is meant by ‘Cell Cycle’?
Where cells grow and divide, over and over again.
What are the three stages of the cell cycle?
Interphase, Mitosis and Cytokinesis
What is the interphase?
The cell gets ready to divide. The cell grows, DNA duplicates and more organelles are made.
What is Mitosis?
The genetic material separates to different ends of the cell, and the cell gets ready to divide into two daughter cells.
(See and study diagram).
What are the four main stages of Mitosis
During mitosis the following events occur:
Chromosomes replicate, resulting in X-shaped chromosomes with two ‘arms’ known as chromatids
The chromosomes line up along the equator of the cell
The chromatids are separated and pulled to opposite ends of the cell
A new nucleus forms around each new group of chromosomes
Mitosis occurs in all eukaryotic cells, why?
Replacing skin cells
Growth of an organism
Asexual reproduction (Plants)
What is cell differentiation
Where a cell becomes specialised for a specific purpose.
How are palisade leaf cells specialised for their purpose?
Tall shape - have a large surface area.
Thin so there are more of them, closer to the light.
What are the specialised adaptations of a sperm cell?
Long tails and streamline head - easy to swim.
Lots of mitochondria to give the cell energy.
What are stem cells and where are they found.
Undifferentiated cells (have the ability to turn into any cell), mainly found in embryos
But,
can be found in adult bone marrow (but cant go into any cell)
In plants, where are the stem cells found?
Meristems.
What is diffusion?
Movement of particles from an area of high concentration to a lower concentration.
What is active transport?
Active transport is the movement of cells/ions across a cell membrane from a region of lower concentration to a region of higher concentration
Only one that requires energy
What is osmosis?
Osmosis is the net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water.
A special case of diffusion for water.
Partially permeable membrane = membrane with very small holes in
What is water potential?
The potential of water molecules to diffuse into or out of a solution.
How does osmosis work when watering a plant and why do the leaves stay in place?
When watering a plant, you increase the water potential around the soil.
The water is drawn in through osmosis. This happens until the cells become turgid. (Plump and swollen). This helps keep the plant upright and in shape.
If you didn’t water a plant, the cells would become flaccid and droop.
What are the three main factors that affect active transport, diffusion and osmosis?
Surface area- more space, more movement
Temperature - warmer then particles more faster, move quicker between concentration gradients
Concentration gradient - bigger difference in concentrations
Describe the particle for investigating the effects of Osmosis
Cut ups cylinders of potato (or other starchy veg) - and weigh
Add into test tubes of different sugar solution concentrations
24hours later- Re weigh and calculate percentage change.
Percentage change = final - initial mass / initial mass x100
When plotted on a graph, where it hits the x axis, is typically the concentration of the vegetable normally.
What is a cells with (a. 23 pairs) of chromosomes and (b. 23) chromosomes called.
A. Diploid
B. Haploid
What are the advantages of cloning (from stem cells)?
Helps endangered species and crops.
