GCSE Cells & Biochemistry Knowledge Flashcards
what are the functions of white blood cells?
- ingest pathogens
- produce antibodies
- produce antitoxins
what does producing specific antibodies to kill a particular pathogen lead to?
immunity from that pathogen
what happens if a large proportion of the population is immune to a pathogen?
the spread of the pathogen is very much reduced
what are the effects of exercise on the body?
- increase rate of breathing
- increase depth of breathing
- increase heart rate
what is the organisation of cells, tissues, organs etc. in the stomach?
muscle cells –> muscle tissue (contract to churn bits of food)
glands –> glandular tissue (secrete acid, enzymes & hormones)
epithelial cells –> epithelial tissue (line the stomach to protect it from HCl acid)
what can be transferred by evaporation?
heat
what is the specific heat capacity of water?
high
describe the interaction between oil & water?
oil does not dissolve in water
it can form emulsions with water if an emulsifier is present
are vegetable oils saturated or unsaturated?
how can they be hardened?
unsaturated bc they contain a double bond
these may be hardened by hydrogenation to add to the double bond
what are the roles of protein in the body?
enzymes
structural components e.g. muscle
antibodies
hormones
what is chromatography used for?
to separate mixtures of soluble dyes
& to identify molecules within a mixture
what are needed in small amounts for the body to function healthily?
mineral ions & vitamins
how are ions lost from the body?
- via the skin in sweat
- excess ions are lost via the kidneys in urine
what ions make a solution acidic?
H+
what is energy from respiration used for?
movement
protein synthesis
synthesis of amino acids in plants
maintenance of constant body temperature
what does DNA contain the genetic information for?
features & characteristics
what do mutations cause?
new forms of genes
what does Darwin’s theory of evolution by natural selection state?
all species of living things have evolved from simple life forms that first developed more than 3 billion years ago
why do individual organisms within a species show variation?
differences in the genes they inherit,
the conditions in which they develop
or both
where there are new forms of genes (caused by mutations), what can happen if the environment changes?
rapid change in a species
what does studying the similarities & differences between organisms allow?
classification of organisms to understand evolutionary & ecological relationships
what is a species?
a group of organisms that can interbreed to produce fertile offspring
how does fossil evidence show how species have changed over time?
fossils are: evidence of early life forms
the best evidence of organisms that are now extinct
the remains of organisms from millions of years ago found in rocks
how are fossils formed?
- animal traces e.g. footprints, burrows, rootlets
- animal decayed so left space that was filled by minerals
- parts of organism had not decayed because a condition for decay was not present (e.g. anaerobic, low temp, low pH, low moisture)
what cause new species to arise?
- isolation - 2 populations of the same species are separated
- genetic variation - each population has a range of alleles that control their characteristics
- natural selection - alleles that control the most beneficial characteristics (that help the organism to survive) are selected
- speciation - populations become so different that they can no longer interbreed successfully to produce fertile offspring
