Biology Flashcards
what is a specialized cell
cells designed to carry out a particular role in the body,
what is differentiation
the process by which a cell changes to become more specialised for its job
what happens to the ability of differentiation to an animal cell when it gets older
it is lost
what are stem cells in already mature animals used for
to repair and replace cells
which cells are usually replaced or repaired in animals
blood and skin cells
what is the difference between adult and embryonic stem cells
adult stem cell ability to differentiate is limited while an embryonic stem cells ability is not
where in plants are stem cells found
the meristem
what can plant stem cells do that animal stem cells can’t
they can differentiate throughout their whole life
what can these plant stem cells be used for
they can grow more plants of rare species
they can be used to produce plant clones quickly and cheaply
grow plants with more desired features
What are chromosomes
coiled up lengths of DNA
what do chromosomes carry
genes
what do genes control
development of different characteristics
how many chromosomes are there
23
how many copies of each chromosome does each body cell have
2
what are the stages of the cell cycle
Growth and DNA Replication
Mitosis
what happens in a cell that’s dividing
it increases the amount of sub-cellular structures E.G. Mitochondria and ribosomes
what happens to the DNA in a cell that’s dividing
it gets duplicated so there’s on copy for each new cell
what happens to the cell in mitosis
1.chromosome’s move to centre of cell
2.cell fibres pull them apart
3.two arms of each chromosome go to opposite ends
4.membranes form around each chromosome
- each set of chromosomes become nucleuses
- cytoplasm and cell membrane divide
what controls the rate of chemical reactions
enzymes
what are enzymes
Biological catalysts
How do enzymes work
they work using the lock and key method
the enzyme has an active site
substrate fits into active site
substrate splits into products which leave the active site
enzyme ready to use
how were drugs traditionally obtained
plants or microorganisms known as moulds
examples of drugs from plants
digitalis
digoxin
aspirin
what is digitalis and digoxin used for
strengthen heartbeat
how are most drugs made now
most are synthesised in a lab by chemists
What is the purpose of the nervous system
To detect and respond to stimuli
What organs are in the central nervous system
the spinal cord and the brain
What are sensory neurones
The neurones that carry electrical impulses from the receptors to the central nervous system
What are motor neurones
neurones that carry electrical impulses from central nervous system to the effectors
What are effectors
all the muscles and glands that respond to nervous impulses
What are receptors
Cells that detect stimuli
What receptors are in the eye
light receptors
What is the connection between two neurones called
synapse
How is the nerve signal transferred between two neurones
chemicals diffuse across the gap
chemicals set off new signal once reached other neurone
What are hormones
Chemical messengers that travel in the blood that target specific organs
What qualities do hormones have
slower effects
the effects last for a long time
the effects act in a more general way
What qualities do nerves have
the effects are quicker
the effects last for a short amount of time
the effects act on a precise area
What are some examples of endocrine glands
pituitary gland
ovaries
thyroid
testes
adrenal gland
pancreas
What hormone do the ovaries produce
oestrogen
How does oestrogen affect the body
causes the lining of the uterus to grow
stimulates the release of LH
Inhibits the release of FSH
How does FSH affect the body
causes egg to mature in follicle
stimulates ovaries into producing oestrogen
Where is FSH produced
pituitary gland
How does LH affect the body
stimulates the release of an egg at day 14
Where is LH produced
produced by the pituitary gland
How does progesterone affect the body
maintains lining of uterus during the second half of the cycle
inhibits the release of LH and FSH
What hormone does the thyroid produce
thyroxine
How does thyroxine affect the body
thyroxine regulates metabolism
stimulation of protein synthesis for development
What hormone does the adrenal gland produce
adrenaline
How does adrenaline affect the body
puts you into flight or fight mode
What hormones are produced by the pancreas
insulin and glucagon
How does insulin affect the body
reduces the amount of glucose in the blood
How does glucagon affect the body
increases the amount of glucose in the blood
how does insulin remove glucose from the blood stream
it causes excess glucose to move from the blood to the liver and muscle cells by telling all cells to absorb glucose which is then stored as glycogen
How does glucagon add glucose to the blood stream
causes stored glycogen in the liver and muscle cells to be converted back to glucose and move back into the bloodstream
What does genotype mean
The genotype is the collection of alleles that determine an organism’s characteristics.
what does phenotype mean
the phenotype is the physical characteristics that an organism displays
What is it called when someone has two different alleles
Heterozygous
what is it called when someone has two alleles that are the same
homozygous
What is an Allele
A variation of a gene
What is homeostasis
The process of maintaining a stable internal environment
What is meiosis
the cell division in which gametes are produced
What are the steps of Meiosis
Chromosomes are duplicated and then arrange themselves in pair
first division - chromosomes line up at centre of cell in pairs then are pulled apart so each new cell only has one copy of each chromosome- the cell has some of the fathers and some of the mothers chromosomes
second division - chromosomes line up at centre of cell and are then pulled apart at the arms to create 4 new gametes
How is Meiosis different from Mitosis
You get four gametes
gametes are genetically different from each other
Each only have half the amount of chromosomes
What is Active transport
The process in which molecules move from an area of high concentration move to an area of low concentration across a cell membrane
What is the disadvantage of Active transport
It requires energy from the cell to work.
What does the peripheral nervous system contain
All the nerve cells that carry information to or from the CNS
What things do all control systems need
Receptors
Coordination centers- brain, spinal cord, pancreas- they receive and process information around the body
Effectors
What is another name for nerve cells
Neurones
What is a bundle of neurones called
A nerve
What are the three main types of neurons
Sensory, Motor, Relay
What is the nerve path from an Receptor to an Effector
Receptor–> sensory neurone–> relay neurone–> CNS–> relay neurone–> Motor neurone–> effector
What are sensory organs
Sensory organs are organs that contain receptors that respond to specific stimuli
What are some examples of sensory organs and their stimuli’s
Skin- touch, pain, temp
Tongue- chemicals in food and drink
Nose- chemicals in air
Eye- light
Ears- sound and position of head
What is a reflex action
Automatic and rapid response to a stimulus
What is a reflex arc
The nerve pathway followed by a reflex action
Where are relay neurons located
The spinal cord
How do your automatic control systems keep your internal environment stable
They keep our internal environment stable through a mechanism called negative feedback
What is negative feedback
When the level of something in the body gets too high or low the body will get the effectors to produce a response to counteract the change and restore the optimum level of the thing
What is type 1 diabetes
When the pancreas produces little to no insulin
What is type 2 diabetes
When a person becomes resistant to their own insulin- body produces insulin but cells don’t respond properly to hormone
What is the development of new species called
Speciation
What is the main problem of selective breeding
it reduces the gene pool- could lead to inbreeding + less variation in genes in population
What are the steps of genetic engineering
A useful gene is isolated from one organisms genome using enzymes and is inserted into a vector
The vector is usually a virus or bacterial plasmid depending on the type of organism that the gene is being transferred to
When the vector is introduced to the target organism, the useful gene is inserted into its cells
Who proposed the three domain system
Carl Woese
When was the three domain system proposed
1990
What are the three domains of the three domain system
Archaea- primitive bacteria- a group of micro-organisms that are similar to, but evolutionarily distinct from bacteria.
Bacteria- true bacteria- often look like Archaea but have lots of different biomechanical processes
Eukaryotes-organisms whose cell has a nucleus- fungi, plants, animals and protists(single celled eukaryotes)
In the Linnaean system how are animals separated/ grouped
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
What are abiotic factors
Factors that are not alive
What are biotic factors
Factors that are alive
What are some examples of abiotic factors
Moisture level
light intensity
Temperature
Carbon dioxide level
What are some examples of biotic features
New predators
increase in competition
new pathogens
