SB2 Flashcards
Diploid cells
Cells with two copies of each chromosome
Haploid
Cells that contain one of each type of chromosome (e.g gamete)
DNA replication
Making copies of all the chromosomes
Mitosis
Cell division. The cell splits to form two daughter cells, which are both identical to the parent cell.
Cell differentiation
Changing less specialized less into specialized cells.
Why does a red blood cell have no nucleus
To allow more space for red hemoglobin molecules (which carry oxygen) Also larger surface area to allow oxygen to diffuse in and out quicker.
Why do nerve cells have long fiber
It carries electrical impulses around the body and connects it to other neurons
Muscle cells
Contain special contractile proteins that can shorten the cell
Cytoplasm of fat cells
The cytoplasm if filled with large fat droplets. The fat is stored until the body needs energy
Measuring growth
Final value-starting value/ starting value *100
Meristems
Groups of cells near the end of each shoot and root that allows plants to continue growing throughout their lives
Elongation
Cells that increase in lengths
Palisade cells
Plant cells found inside leaves near the top surface. Their main function is photosynthesis.
Stem cells
Cells that can divide repeatedly over a long period of time to produces cell that differentiate are called stem cells
Embryonic stem cells
The cells of an early age embryo
Adult stem cells
By the time the animal is fully developed, the stem cells can usually only produce the type of specialized cells that is in the tissue around them. Adult stem cells in human tissues allow the tissues to grow and replace old or damaged cells
Rejection
Sometimes, stem cells from one person are often killed by the immune system of other people that they are put into
Neurons
Nerve cells
Central nervous system
The brain and the spine form the CNS, which controls your body. Nerves make up the rest of the nervous system which allows all your body parts to communicate.
Impulses
Electrical signals
Stimulus
Anything your body is sensitive to, including changes inside your body and your surroundings.
Receptor cells
Cells that detect stimuli and then create impulses to send to the brain. The brain processes this information and then sends impulses to your body to cause a response
Neurotransmission
The traveling of impulses.
Sensory neuron
It’s function is to carry impulses from a receptor cell towards the CNS.
Dendrite
An impulse passes through a tiny branch called a dendrite.
Dendron
The impulse is passed to the dendron from the dendrite, and then passed through the axon.
Axon terminals
Takes the impulse from the axon and transmits it to other neurons
Myelin sheath
A fatty layer surrounding the dendron and axon, which insulates the neuron to stop the signal from losing energy. It also males and impulse jump along the ell between gaps in the myelin.
Motor neuron
Carries impulses to effectors
Synapses
One neuron meets another at a synapse. which is a gap. When an impulse reaches an axon terminal, a neuron transmitter substance is released into the gap. This is detected by the next neuron, which generates a new impulse. Synapses slow down neurotransmission.
Reflex arc
Neuron pathways that bypass the parts of the brain involved so that the responses are quicker (you dont have to process the information first, instead you just act on the stimulus)
What happens in mitosis
Interphase- duplicate chromosomes before mitosis starts
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prophase- nucleus is still present, chromosomes are condensing
metaphase- nucleus is disassembled, chromosomes line up in middle of cell
anaphase- chromosomes move to opposite sides of the cell (spindle fibers move them)
telophase- new nuclei are forming on each side of the cell
cytokinesis- splits into two cells
