(P1) Topic 2: Cells And Control Flashcards
What are the stages of mitosis in plants
Prophase
Metaphase
Anaphase
Telophase
What are the stages of mitosis in animals
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
What occurs in interphase
The cell grows, replicates its chromosomes, and prepares for cell division
What occurs in prophase
Condensing
What occurs in metaphase
Chromosomes line up, nucleus dissolves
What occurs in anaphase
Chromatids move towards the poles of the cell
What occurs in telophase
Chromosomes are at the poles, two nuclei form
What occurs in cytokinesis
The cell splits
Why does mitosis need to occur
Cells need to divide for growth and repair
What are the products mitosis
Two genetically identical daughter cells
What does fertilisation create
A zygote
Where to totipotent stem cells come from
Zygote
Where to multipotent stem cells come from
Embryo
Where to pluripotent stem cells come from
Adults
How many versions of each chromosome does each cell have
Two, one from each parent
Explain how mitosis works (steps + explanation)
- To prepare for cell division, each chromosome is copied (prophase)
- The chromosomes line up in the middle of the cell (metaphase)
- The chromosomes are pulled apart (anaphase)
- The cells separate (telophase)
Issues people have with embryonic stem cells
Christian view- it’s seen as taking a life
Ethical + economic issues
What are stem cells
Undifferentiated cells that can be differentiated into other cells
Where are stem cells found in plants
In the meristem
What type of neurones make up the brain
Relay neurones
What is a nerve cell
A collection of neurones
What is the optic nerve made of
Sensory neurones
Why does the brain have no sense of touch or pain
There are no sensory neurones
What are brains mainly made of
Fat
What is the term that means the brain can mend
Neuroplasticity
What is controlled by the cerebral cortex
Thinking- memories, emotions, conscious decisions, personality
What is controlled by the cerebellum
Sensory component- sight, smell, taste
What so controlled by the medulla oblongata
Autonomic functions- breathing, blinking, heart beating
What is the synapse
Functional gap between two neurones
Simple reflex arc
stimulus -> receptor -> sensory neurone -> relay neurone (CNS) -> motor neurone -> effector -> response
Where in the body are photoreceptors located
In the eye
What do photoreceptors function as
Transducers in converting the external energy of light stimuli into the code of the nervous impulse
What does a photoreceptor do
Detect light
What is a transducer
Something that can turn energy into another type of energy
What part of the mammalian eye are the photoreceptors
The rods and cones
What are the rods for
Detecting light level
What are the cones for
Detecting colour
What part of the eye is responsible for controlling the amount of light entering the eye and how does it do this
The muscles of the iris, by adjusting the size of the pupil accordingly
What does the cornea do
Protects the pupil
What does the pupil do
Lets in light
What does the iris do
Controls the size of the pupil
What is the sclera and what does it do
It is the white part of the eye that controls the amount of light in by reflecting light. This prevents over-exposure
What is formed when light rays from all points on an object within field of view are focused onto the retina
An inverted image
Where are the rods and cones located
In the retina
What is the name for a light particle
A photon
Do rod and cones cells contain mitochondria
Yes- to have energy to convert energy into different forms
What is released in rods when it is dark
Neurotransmitters
Characteristics of cones (3)
-discrimination of colour
-good visual activity (resolution)
-poor sensitivity
Characteristics of rods (3)
-Monochromatic vision
-poor visual activity (resolution)
-good sensitivity
What is the theory of trichromatic colour vision
Three varsities of colour-sensitive pigment located in separate cone cells in the retina- different colours and shades are perceived by the degree of stimulation of each type of cone
Approximately how many cones are located in the retina
6 million
