Biology Flashcards
What is homeostasis?
The maintenance of a constant internal environment
What is a stimulus?
Anything that triggers a change in the environment of an organism
What makes up the nervous system?
Our brain, spinal cord and all nerves throughout our bodies
In what order does your body respond to a stimulus?
Stimulus, receptor, sensory neurone, co-ordinator, motor neurone, effector, response
How are reflexes faster than normal responses?
Reflexes reduce the number of synapses they pass and avoid the brain
Why are reflexes important?
Reflexes help to keep us safe and protect our bodies from things that can harm us
What is a neurotransmitter?
A chemical that is released by a synapse
Why do we have internal receptors?
To monitor the environment inside our body and keep us at our optimum
What is the stimulus for the eyes?
Light
What is the stimulus for the skin?
Changes in temperature or pressure
What is a receptor?
Cells that detect changes in the internal or external environment
What is a co-ordinator?
Receive and process information from the receptor then send signals and coordinate the response
What is an effector?
Muscles or glands that bring about the response
What are the three main types of nerves?
Sensory nerve, relay nerve, motor nerve
What experiment can be used to measure reaction time?
Ruler drop test
What do animals compete for?
Sex, food, shelter, water
What is it called when animals compete with members of the same species?
Intraspecific competition
What is it called when animals compete with members of a different species?
Interspecific competition
In what ways do male animals compete for females?
Fight, display themselves or dance.
What is an allele?
Variant form of a gene that occurs at a specific location in the chromosome
What is a gene?
A section of dna which controls part of a cells chemistry
What is homologous?
A term that describes having the same relation, relative position, or structure
What is heterozygous?
A term that describes having two different versions of the same gene
What is a phenotype?
A set of observable characteristics or traits in an organism, such as its physical, biochemical, or behavioural traits
What is a genotype?
The genetic constitution of an individual organism
What does recessive mean?
Heritable characteristics controlled by genes which are expressed in offspring only when inherited from both parents
What does dominant mean?
A dominant trait or gene, only need one parent to have this gene for it to be passed on
What is a gamete?
A mature haploid male of female germ cell which is able to unite with another of the opposite sex in sexual reproduction to form a zygote
What does codominant mean?
A type of inheritance in which two alleles of the same gene are expressed separately to yield different traits in an individual
What is mutation?
A random change in the DNA structure of a gene or chromosome
What is variation?
The difference between individuals of the same species, caused by genetic and environmental factors
