Topic 3 Flashcards
what is the structure of bacterial Dna
circular with no nuclear membrane
Describe how DNa is organised in a bacterial cell
large cicular dna
small plasmids
located in cytoplasm not in nucleus
Describe what happens to lysosomes once there contents have been released
lysosome fuse with cell membranes contents released from the cell via exocytosis
3 differences between eukaroytic and prokaryotic organisms
eukaroytic organisms have membrane bound organelles
eukaroytic organisms have a nucleus prokaryotic dont
size of ribosomes larger in prokaryotic
eukarotic organisms dont have plasmids.
what happens to lactate when it is absorbed from the blood
lactate is converted to pyruvate which is used in respiration
3 features that could be used to identify prokaryotic cells in a blood sample
no nucleus
plasmids
smaller ribosomes
circular dna
presence of cell wall
explain why the nucleus cannot be observed at the end of the prophase in a eukaryotic cell
end of prophase nucleus is pulled apart by spindle fibres meaning it isn’t in tact to observe
two functions of golgi apparatus
modifies proteins
forms vesicles
3 phases of developing a new drug
find safe dosage
see if drug is effective
gather data too test for rare side effects
where is the bacteria capsule located
outside the cell
what does the term polygenic mean
a characteristic showing continuous variation caused by multiple genes at different loci
explain how epigenetic changes affect the development of tissues in the embryo
dna is wrapped around histones
modification of the histones prevents chromosome unwinding
therefore gene expression is faulty
deduce why people with a mutation of a gene for a particular protein makes them resistant to HIV
the receptor that binds to HIV is unable to bind with the receptor so HIv cannot enter the cell
explain why stem cells can help prevent HIV causing aids
stem cell can differentiate into any cell
they can differentiate into T helper cells which are resistant to HIV
T helper cells can also be destroyed by HIV which prevents the patient from producing a immune response
due to these t helper cells being destroyed HIV isn’t present in the blood
one difference between a tissue and a organ
tissue is made up of one type of cell and a organ is made up of different tissues
describe the decisions that society has to make about the use of embryonic stem cells
embryonic stem cells are totipotent meaning they can be used in a wide range of treatments and therapies
source of embryonic stem cells has to be considered
unethical as the use of them destroys embryos
need for licensing and regulation.
what is a totipotent cell
a cell that has the ability to differentiate into all cell types
describe how a cell becomes specialized
chemical signals cause some genes to be turned on. Activated genes are transcribed to produce mRNA mRNA leads to the synthesis of specific proteins which causes cell modification
explain why stem cells from the heart cannot be used to grow cells to repair the cornea
cells are not totipotent
therefore some genes have already been switched on or off therefore wont be able to specialize into cornea cells
explain why chemicals from the eye are needed to produce corneal cells to repair the cornea
chemicals cause some cells to be activated or deactivated .these turned on genes are transcribed using mRNA. specific mRNA can be translated into specific proteins. This caused the cell to develop into a corneal cell
deduce why age affects time taken to recover from injuries
time taken to recover will increase with age
due to fewer stem cells with age and therefore less to replace damaged cells in muscles and bones
what is meant by the term stem cell
a cell that is undifferentialised that can divide to produce more stem cells
compare the contrast the results of mitosis and meiosis in the production of sperm cells and stem cells
similarity=both increase number of cells
differences=mitosis produces diploid cell and meiosis produces haploid cells
meioisis=genetically different cells produced-2 daughter cells
mitosis=genetically identical cells produced-4 daughter cells
what is a sex linked disorder
a disorder caused by a faulty gene located on the x/y chromosome therefore the disorder is more likely to occur in one gender more than the other
explain why the genotype of males cannot be calculated using the hardy weinberg equation
males only have one allele for this gene
males cannot be heterozygous
hardy weinburg equation assumes all individuals have two alleles for the same gene
explain how a change in epigenetic changes causes a difference in characteristics
histone modification affects how a gene is activated and deactivated which affects enzyme production
explain how epigenetic changes affect the activation of genes in daughter cells
explain why a individual may have a greater adult height than their parents
what is a polygenetic characteristic
multiple alleles at multiple loci
what is the term that refers to the inheritance where a single characteristic is determined by more than one gene
polygenic
which factor could affect the development of lupus
diet
explain how a tissue differs in structure from a system
tissue contains one type of cell a system contains many different tissues
describe how mesenchymal stem cells can give rise to different types of cell
different stimuli activate different genes
genes are transcribed
mRNA translated to produce proteins
proteins determine structure and function of cells
resulting in a different type of cell being produced
explain how a mutation of a gene which causes a inhibition of a enzyme can increase the risk of the development of cancer
what does hydrolic acid make a plant more observable
breaks down middle lamela so that light can pass through
how does adding a stain make a plant cell more visible
stains makes structures visible this makes stages of mitosis visible
explain how preventing shortening of spindle fibres affects mitosis
sister chromatids cannot be seperated
mitosis stops at metaphase so anaphase cannot occur
daughter cells produced have incorrect numbers of chromasome
