Chapter 2 Flashcards
Names and order of stages in mitosis
Prophase
Metaphase
Anaphase
Telophase
Describe what happens in each stage of mitosis
Interphase- a cell has 2 versions of each chromosome, one from each parent- diploid
Prophase- each chromosome is copied to ensure each cell has a full genome, the chromosomes condense and nucleus disappears.
Metaphase- chromosomes line up in the middle
Anaphase- chromosomes move apart=chromatids. The two copies of each chromosome are pulled apart by spindle fibres.
Telophase- chromosomes move to different sides of the cell, the cell completely splits in two. There are now two cells, these are called daughter cells, each cell is genetically identical to eachother and to the original parent cell
What is mitosis for?
Growth, repair and asexual reproduciton
How does mitosis produces genetically identical diploid cells
Cell copies its chromosomes then splits the copied chromosomes equally to make sure that each daughter cell has a full set
Describe the division of a cell by mitosis
The production of two daughter cells, each with identical sets of chromosomes in the nucleus to the parent cell, which results in the formation of two genetically diploid body cells,
What is cancer
A result of changes in cells that leads to to uncontrollable cell division
How do cancers grow
Sometimes cells in part of a multicellular organisms divide uncontrollably causing a lump ;The result is a large mass of cells called a tumor. If tumor cells successfully invade other tissues in the body the result is cancer.
How to describe growth in organisms
animals and plants
animals=cell division and differentiation
plants= elongation and differentiation in plants
Explain the importance of cell differentiation in development of specialized cells
So animal cells can differentiate into specific / specialised cells for specific functions for the body
Function of stem cells in plants and animals
Treat diseases
Replace cells
Grow limbs
Testing new drugs
Differences between embryonic and adult stem cells
Embryonic stem cells come from an undeveloped embryo and can develop into any type of cell, whereas adult stem cells are unspecialised cells that can develop into many (not all) types of cell.
Function of…
Embryonic stem cells
Stem cells in animals
Meristems in plants
Embryonic stem cells- can be developed into any cell, they can be used to make new brain cells for people with Parkinson
disease
Stem cells in animals-
Meristems- Divide to produce cells that increase height of plant, length of root or cells for leaves and flowers.
Name the 3 main parts of the brain
Cerebellum
Cerebral hemisphere
Medulla oblongata
What does the cerebellum do
Receives information from the sensory systems. It coordinates voluntary movements such as posture, balance, speech etc
What do both the cerebral hemisphere do
Right coordinates left and left coordinates the right.
Function of the medulla oblongata
Centre for respiration and circulation, it helps regulate breathing, digestion, Betsy and blood vessel function.
Sensory and motor neurons travel through the medulla
How can the difficulties of accessing brain tissue inside skull be overcome
Using CT scanning and PET scanning
Effects of spinal cord damage
Back pain
Pressure in neck or head or back
Weakness
Incoordination or paralysis in any part of body
Numbness
Tingling
Loss of sensation in hands fingers feet or toes
Effects of damage to different parts of the brain
Cerebellum- loss of ability to walk, coordinate fine movements, slurred speech and dizziness.
Cerebral hemispheres- if injury was sustained to the left side of the Brain the right side would be effected eg- paralysis of limbs
Medulla oblongata- stop swallowing, drooling and
Paralysis
Why can’t some types of spinal cord damage not be repaired fully
Some cells of the central nervous system are so specialized that they cannot divide and create new cells
Parts of the nervous system
Brain and spinal cords, and nerves (neurons)
How does the nervous system detect stimuli
Receptors are located in the sense organs e.g. Ear eye and skin. Each organ has receptors sensitive to particular kinds of stimuli
List the main parts of the eye
Cornea
Lens
Iris
Retina
Explain how the cornea, lens, iris and retina are adapted to their functions
Cornea- convex and transparent. It refreacts light as if enters the eye
Lens- transparent, bi convex. It focuses light onto the retina
Iris- pigmented, eye colour is decided by iris. , Responsible for controlling the diameter and size of the pupil (by muscle contraction) and thus the amount of light reaching the retina.
Retina- back of the eye containing 2 cells, a rod that’s sensitive to dim light and bw and cones that are sensitive to color. CONTAINS LIGHT RECEPTORS
Common eye defects
Cataracts
Long/short sightedness
Colour blindness
How are cataracts treated
Improved with sunglasses or , magnifying
Lenses. OR surgery can. Remove cloudy lens and replace it with an artificial lens
Recall the 5 steps of a human detecting a stimulus and how we react
Receptors detect stimulus
Sensory neuron Carries message from receptor to CNS
Central nervous system
Motor neuron carries message from CNS to effector
Effector (muscles& glands )
What’s the first thing to detect a change/stimulus
Receptors- found in our sense organs
reflex arc
Reflex arc is automatic and doesn’t require the brain therefore conserves energy and power e.g.- walking- reflex arc in foot
What is the structure of a neuron like
Dendrites (branched endings) connected to dendron and an axon and to end - an axon terminal
What is the coating on dendrons and axons called and what does it do
It’s called a Myelin sheath and stops interference between neurons- insulator
What’s a synapse and how does it work
It’s the gap between neurons
It works as an impulse causes a release of a neurotransmitter chemical, this chemical diffuses across the synapse and the chemical binds to receptors on the next neuron
What is a meristem
The area in plants where cell division (mitosis) occurs.
What does the sensory neuron do
Carry signals from receptors (organ which recognises and responds to stimuli) to the spinal cord and brain.
What does the relay neuron do
Carry messages from one part of the CNS to another.
What does the motor neuron do
Carry signals from the CNS to effectors (muscle reaction/action)
Function of dendrites
Branch like structures at the start of the neuron that receive electrical messages
Function of dendron
Nerve fibres that transmit nerve impulses towards the cell body
Function of axon
Long projection of a nerve cell that conducts electrical impulses away from the neurons body and Transmits information to different neurons muscles and glands
Axon terminal function
Releases the neurotransmitters over the synapse
What is cytokinesis
The final part of the cell cycle after mitosis in which the cell splits in two and new nuclei is formed
What is interphase
Active life of a cell during which the cell prepares for division in mitosis
What does it mean to differentiate
To specialise or adapt to a specific function.
What’s a clone
An organism produced asexually so it has identical genes to its parents
What does totipotent mean
Describes embryonic stem cells as they can turn into any specialised cell
What does multipotent mean
Describe Stem cells in mammals as they can only turn into cells located where that cell is eg- if it’s in tissue area it will turn into tissue celll
What’s cytokinesis
Last stage of mitosis were the cytoplasm moved and the cell membrane pinches in=cleavage
What does haploid mean
Having half the normal number of chromosomes-23 chromosome
What does diploid mean
Having the normal number of chromosomes -46 chromosomes
What’s a zygote
Cell formed when two gametes combine
How does a ct scan work
X
How does a PET scanner work
X
Explain DNA extraction experiment
Chop fruit up into tiny pieces
Add salt and dertegent to fruit and stir, detergent helps break down cell membrane and sal helps make DNA stick together.
Put beaker in water bath 60* for 15 mins.
Add Iced ethanol and DNA should float to the surface as it separates from cells as a white stringy substance-removed by glass rod
