Paper 1 - Topic 2, Cells And Control Flashcards
What are adult stem cells
Stem cells that can differentiate into a limited range of cells
What is asexual reproduction
A form of reproduction involving one parent that creates genetically identical offspring
What is an axon
A long fibre that conducts nerve impulses away from the cell body
What is cancer
A non-communicable disease caused by changes in the cell that lead to uncontrolled growth and division
What is a cataract
A cloudy patch that forms on the lens of the eye and prevents light entering normally
- people affected have blurred vision, difficultly seeing the intensity of colours and problems with glare
What is the cell cycle
A series of events that take place in a cell involving cell growth, DNA replication and cell division
What is cell differentiation
The process by which an undifferentiated cell becomes specialised for its function
What is cell elongation
The process where cells expand and enlarge enabling the growth of a plant
What parts of the body make up the central nervous system
Brain and spinal cord
What is a chromosome
A long, coiled molecule of DNA that carries genetic information in the form of genes
What are cone cells
Cells found in the retina that are sensitive to high intensity light and they detect different colours
What is the cornea
The transparent outer covering that reflects light entering the eye
What are dendrites
Short, branched extensions of dendrons that provide a large SA to receive nerve impulses from other neurons
What is a dendron
Branched extensions of a nerve cell body that connects to other neurones and carry impulses towards the body
What is a diploid cell
A cell that contains two copies of each chromosome
What is an effector
An organ, tissue or cell that produces a response to a stimulus
What are embryonic stem cells
Stem cells found in very early embryos that are unspecialised and capable of differentiating into any cell type
What is a haploid cell
A cell that contains a single copy of each chromosome
What is the iris
A pigmented ring of muscles that controls the size of the pupil to alter how much light enters the eye
What is the lens
A transparent, biconvex structure that refracts light focusing it on the retina
What causes long sightedness
When the eyeball is too short or the lens is too elastic
What is the medulla oblongata
The region of the brain that regulates unconscious activities like breathing
What is the meristem tissue
Plant tissues containing undifferentiated stem cells
What is mitosis
Cell division that produces two genetically identical daughter cells with a full set of chromosomes from one parent cell
What is a motor neurone
A neurone that carries nerve impulses from the central nervous system to the effectors
What is the myelin sheath
An electrically insulating layer that surrounds the axon and increases the speed of nerve cells
What are neurones
Nerve cells adapted to quickly transmit never impulses
What are neurotransmitters
Chemicals that are used for communication between neurones and their target cells