S4 Topic Tests 1 Flashcards
What is the process by which new cells are made
Cell division
What are some uses of cell division
. Growth of multicellular organisms
. Repair of multicellular organisms
. Asexual reproduction of unicellular organisms
What is stage 1 of mitosis
The chromosomes begin to coil up and condense
What is stage 2 of mitosis
The chromosomes now appear as chromatids held together in the middle by a centromere
What is stage 3 of mitosis
The nucleus membrane breaks down a dm the chromosomes now line up on the equator of the cell
What is stage 4 of mitosis
Spindle fibres form and separate the chromosomes into chromatids and drag them to opposite poles of the cell
What is stage 5 of mitosis
The nucleus membrane now reforms around each daughter cell as well as the separated cell wall
What is the chromosome complement
Chromosome complement is when no chromosomes are lost meaning no genetic information is lost. Mitosis maintains the chromosome complement
What is a diploid cell
A cell with two sets of genetic information
What is a haploid cell
A cell with one set of genetic information
What are stem cells
Unspecialised cells that can turn into any cell in the body
What are the two reasons stem cells divide
Self renewal
Reproduction
What are the two types of stem cell
Embryonic
Tissue
What are embryonic stem cells
Ones which can produce all the cells in your body regardless of what type they already are
What are tissue stem cells
Ones which can only make cells that are similar to themselves. E.g. blood stem cells can only make other cells that are in blood
What are some ethical issues with stem cells
Destroys embryos which are a potential for life
What are the details of a red blood cell
Bi-concave shape
Increased surface area- more space for oxygen
Contains haemoglobin to carry oxygen
No nucleus- more space for oxygen
What are the details of a root hair cell
Large surface area to allow more water and nutrients to be absorbed
What is the order of organisation in a body’s
Cell-> tissue->organ-> organ system- organism
Tissues are groups of cells
Organs are groups of tissues
Organ systems are groups of organs
Organisms are groups of organ systems
What is the purpose of the nervous system
To respond to changes very quickly
What does the nervous system consist of
CNS
Other nerves
What does the CNS consist of
Brain
Spinal cord
What are nerouns
Specialised nerves which carry information through electrical impulses
What is a gap in between two neutrons called
A synapse
What are the three main types of neutron
Sensory
Inter
Motor
What does the (1) sensory
(2) inter
(3) motor neurone do
(1) carries impulses from receptors to the CNS
(2) transmits electrical impulses to motor neuron
(3) carries impulses from CNS to effectors
How do impulses travel across synapses
Through diffusion which triggers the impulse to start again on the other side
What is the function of the cerebrum and where is it located
Controls memory, personality and conscious thought and is located in the top of the Brian
What is the function of the cerebellum and where is it located
Controls balance and coordination and is located in the bottom right of the brain
What is the function of the medulla and where is it located
Controls heart and breathing rate and is located at the bottom of the brain
REVISE REFLEX ARC DIAGRAM
NOW
Functions of a reflex arc
Protect the body from harm
What are hormones
Chemical messenger in the bloodstream
Revise hormone diagram
Now
Revise blood glucose diagram
Now
What is type 1 diabetes
No insulin produced therefor edit must be injected
What is type 2 diabetes
Cells don’t respond to insulin therefore diet must be controlled and exercise often
What are body cells
Diploid apart from the sex cells
What do animal males produce as their gamete
Sperm cells
What do animal females produce as their gametes
Egg cells or ova
What are the details of a sperm cell
23 chromosome
Around 0.06 millimetres long
Has a long tail for movement and a neck full of mitochondria to produce energy for movement
Head containing nucleus
What are the details of an egg cell
23 chromosome
Around 0.1 millimetres wife
Has a cell membrane and nucleus as well as a jelly layer to only allow one sperm in
Where are egg cells and sperm cells produced
Ovaries and testes
Revise diagram of female and male reproductive organs
Now
What is the male gamete in plant cells
Pollen grains
What is the female gamete in plant cells
Ovule
Where are pollen and ovule cells produced on plants
Anther and ovary
What happens during fertilisation
The two nuclei of the haploid gametes fuse to form a zygote
What is variation
Differences between member so free same species
What are the two types of variation
Continuous and discrete
What is continuous variation
A characteristic that can give an unlimited number of answers
Such as height
Represented by a histogram
What is discrete variation
A characteristic that falls into certain categories for instance blood type
Represented by a bar chart
What is a phenotype
What an organism actually looks like
What is a genotype
The allele sequence of an organism
What is an allele
Different variants of a gene
What is fertilisation
A random process
Do some inheritance problems
Now
What is a dominant allele
The allele that appears most often
What is a recessive allele
One that skips out generations
If a phenotype is dominant it has a … letter
Capital
If a phenotype I recessive it has a … letter
Lower case
The predicted ratio of an f2 generation is
3:1
