cell organelles Flashcards
prokaryotes
unicellular organisms eg bacteria and archaea
eukaryotes
multicellular eg plants,animals,fungi and protoctists
prokaryotes have
70s small ribosomes. cell wall made of peptidoglycan. capsules and plasmids. flagella/pili. cirvcula dna
eukaryotes have
membrane bound organelles like nucleus. 80s big ribosomes. no plasmids and no capsules. linear dna
both prokaryotes and eukaryotes have
cytoplasm ribosomes and cell membarne
ER
network of fluid filled membranes
modifies and folds proteins
difference between RER and SER
SER has ni riboosmes and not attached to nucleus
function of golgi apparatus
trmoves water from protein
Modify and package proteins
forms vesicles /lysoomses
golgi vesicles
Made by golgi apparatus
Store and transport protein and lipids out of the cell
lysosomes
Special type of golgi vesicle
Contain digestive enzymes called lysozymes, which are used to hydrolyse pathogens and old cell organelles
ribosome
made of protein and RNA
nucleolus
makes ribosomes
mesosome
in folding of cell membrane
outside the cell wall
capsule
protective layer outside of cell wall
pilus
transfer plasmids between bacteris
locus
location of genes on a chromosome
how is dna in bacteria organised
circular dna
located in cytoplasm
small plasmids
extracellular enzymes
proteins are foleded in RER
transported in vesicles
vesicles fuse with golgi spparatus
modification of protein inside golgi apparatus
protein packaged into secretory vesicles
exocytosis - vesicles fuse with cell surface membrane
cortical reaction
fusion of sperm cell with egg cell membrane
cortical granules release contents
zona pellucida thickens/hardens
fusion of nuceli
why do some genes show linkage and some show sex-linkage
there are more genes than there are chromosmes
linkage relates to genes on the same choromseome
sex-linkage relates to genes on the sex chroosmeome
fertilised cell divides
by mitosis to produce genticdlly identical cells
crossing over
cgromatids are produced with different combinations of alleles. swapping of sections of chormatids.
how is acrosome involved in the digestion of the zona pellucida
membrane of the acrosome fuses with the plasma membrane of the sperm cell.
releases digestive enzymes
by exocytosis to break down zona pellucida
independednt asortment
different combinations of paternl and maternal chromosmesp[roduced
centriole
spimndle organisation
polygenic inheritance
more than one gene for a single characteristic at different loci
males
can only inherit one allele
nucleus
nuclear pores, double membrane/ envelope, nucleolus
tonoplast
membrane that surrounds vacuole. controls what enters and leaves the vacuole
amyloplast
organelle enclosed by membrane. contain and store starch granules. they convert starch back to glucose for release when the plant requires it
pits
thin regions of the cell wall. they allow transport of substances between cells
sclerenchyma fibres
provide support and have hollow lumen. it is thickened with lignin. more cellulose than other plants. don’t contain pits
what happens to lysosomes once their contents have been digested
they fuse with cell surface membrane
contents released by exocytosis
why cant nucelus be obverved at the end of prophase
nucelar membrane broken down
dna is condensed into individual chromosomes
function of plasmodesma
cytoplasmic connection between cells
allows transport and communication
why is protein made by bacteria different to protein made by animals
bacteria do not have rer
polypeptide isnt properly modified
so protein is incorrectly folded
how does preventing shortening of spindle fibres affect mitosis
sister chromatids cannot be separated
mitossi stops beofre anaphase
why are offspring geneticallt different
random fertilisaiton
gamete contains different combinations of alleles
due to independent assortment/crossing over
sex linked defintion
faulty gene located on x/y chromsome
why abnormal sperm reduces fertility
affects motility
prevents sperm from reaching egg
prevents fertilisation
how is corssing over different in sex chromsomes
crossovers cannot form between x and y chromosme
because they are not homologous
why is dna replicated beefore mitosis beigns
to ensure diploid number of chrosomes in each daughter cell
ensure they are geneticlaly identicla
prophase
nucelar envelope breaks down
chromatids condesne
spindle fibres form
on sex linked, genes are carried on
x chromsoome
molecular phylogeny
molecular differences in DNA in proteins
Compare and contrast the results of mitosis and meiosis
both increase number of cells
mitosis produces diploiod cells/meiosis haploid
meiosis produces genetically different cells/mitosis porduces genetically identical cells
mitosis results in 2 daughter cells/meiosis results in 4 daughter cells
Explain how epigenetic changes can cause differences in a characteristic.
histone modification/DNA methylation
activates genes
affecting enzyme production
Explain why an individual may have a greater adult height than their biological parents.
height is affected by environment aswell as genotype
height is an example of polygenic inheritance
so offspring can inherit a mixture of alleles from boith parents
more caclium in diet (needed for bone growth)/better healthcare can affect height
difference between tissue and system
tissue contains one type of cell
system contains many different tissues/organs
Describe what happens to proteins after translation and before they are released from cell
RER folds protein. Proteins are packaged into vesicle. Vesicle then transports protein to Golgi apparatus, where it is modified, e.g. adding carb group. Vesicles fuse with membrane. Protein is released by exocytosis
primary structure definition
sequence of amino acids joind together by peptide bonds
mutation in enzyme causes?
change in active site
substrate can’t fit in active site
substrate-enzyme complexes can’t be formed
