key terms Flashcards
a light microscope
a tool that uses beams of light and optical lenses to magnify objects
an electron microscope
a tool that uses beams of electrons and magnetic lenses to magnify specimens
magnification
a measure of how much bigger an object is than the real object
resolution
how close two objects can be before they are seen as one
transmission electron micrographs
micrographs produced by electrons that give 2d images like electron microscopes but with higher magnification
scanning electron micrographs
micrograph produced by electron microscopes that have lower mag than transmission ones but seen in 3d
organelles
sub cellular bodies found in cytoplasm of cell
eukaryotes
group of organisms with cells that have genetic material enclosed in membrane
prokaryotes
group of organisms with genetic information not enclosed in membrane bound organelle
cell surface membrane
membrane that forms the outer bound of the cytoplasm and controls what goes in and out of the cell
vesicles
membrane bags that hold secretions made in cells
polar liquids
lipids with on end attached to a polar group
gated channels
protein channels through the bilipid layer opening and closing depending on activity
fluid mosaic model
current model for the phosphobilipid layer
cytoplasm
jelly like substance that makes bulk of cell and contains organelles
nucleus
contains genetic material surrounded by nucleus pores
protoplasm
cytoplasm and nucleus combined
chromatin
granular combination of dna bonded to protein found in nucleus when cell not actively not dividing
nucleolus
dense area of almost pure dna where ribosomes are produced and where division and growth occur
cristae
infoldings of inner membrane which provide large surface area for aerobic respiration
eubacteria
true bacteria
(prokaryotes and organisms)
endosymbiotic theory
suggests mitochondria and chloroplasts lived as independent organelles before living sybmbiotically with other organisms
centrioles
bundle of tubules found near the nucleus involved in cell division by production of a spindle of microtubules that move to each side of the cell
spindle
set of overlapping microtubules running length of the cell formed as centrioles pull apart in meioisis and mitosis
cytoskeleton
dynamic 3d web like structure made of microfilaments that keep web in place and keeps organelles bound
microfilaments
protein fibres that make up part of cytoskeleton
microtubules
protein fibres 20mm in diamater that make up part of cytoskeleton
vacuole
fluid filler cavity in cytoplasm of cell surrounded by a membrane
endoplasmic reticulum
3d network of membrane bound cavities that link to nuclear membrane and makes up large part of transport and synthesis
contracile vacoules
vacuoles that can fill and are empty to help control concentration of cytoplasm of simple freshwater animals
80s ribosomes
found in eukaryotes
site of protein synthesis
made of 60s and 40s
have ribisomal RNA
70s ribosomes
found in prokaryotes
rough endoplasmic reticulum
ER that is covered in ribosomes involved in production and transport of proteins
exocytosis
energy requiring process where vesicle fuses with cell surface membrane so contents are released outside the cell
smooth endoplasmic reticulum
smooth tubular surface without ribosomes involved in transport of steroids and lipids
golgi apparatus
stacks of membranes that modify proteins made elsewhere in cell and package them to transport them
lysosome
organelle full of digestive enzymes used to break worn out cells or digest simple foods
apoptosis
programmed cell death
break down of worn out damaged cells by lysosomes
cell wall
freely permeable membrane around plant cells mainly made of cellulose
suberin
chemical that impregnates cellulose cell walls in cork tissues and make them impermeable
lignin
chemical that impregnates cellulose cell wall in wood and makes it impermeable
middle lamella
first layer of plant cell to be formed when plant cell divides
mainly made of calcium pectate that binds layers of cellulose together
pectin
polysaccharide tht holds cell walls of neighouring plant cells together and is part of primary structure of plant cell wall
primary cell wall
first very flexible plant cell to form with all cellulose microfibrils oriented in a similar direction
secondary cell wall
older plant cell wall in which the cellulose microfibrils built in different angles to each other making cell wall more rigid
plant fibres
long cells with cellulose cell walls that have been heavily lignified so they are rigid and very strong
plasmodesmata
cytoplasmic bridges between plant cell walls that allow comunication between cells
symplast
interconnected cytoplasm of plant cells connected by plasmodesmata
tonoplast
specialised membrane that surrounds the permanent vacoule in plant cells and controls movement of substances in and out of cells
cell sap
aquaous solution that fills vacoule
chloroplast
organelle adapted to carry out photosynthesis contaning green pigment chlorophyll
amyloplast
plant organelles that store starch
tissue
group of specialised cells carrying out specific function
epithelial tissue
tissues that form the lining of surfaces inside and outside the body
hypertonic solution
solution with higher concentration of solutes and lower concentration of water than surrounding solution
peptidoglycan
large net like molecule found in all bacterial cell walls made up of many parralel polysaccharide chains with short peptide cross linkages
pili (fimbriae)
thread like protein projections found on surface of some bacterias
bacteriophages
viruses that attack bacteria
flagella
many stranded helices of the contracile protein flagellin found on some bacteria. they move the bacteria by rapid rotations
mesosomes
infoldings of cell membrane of bacteria
nucleiod
area in a bacterium wheree we find single length of coiled dna
plasmids
small circular pieces of dna that code for specific aspects of the bacterial phenotype
gram staining
staining technique used to tell apart bacteria type from cell walls
gram positive bacteria
bacteria that have technioc acid in cell walls and stain purple blue with staninng
teichoic acid
chemical found in cell walls of gram positive cell
gram negative bacteria
bacteria that have no techoic acid in cell wall and stain red during staning
cocci
spherical bacteria
bacilli
rod shaped bacteria
spirilla
bacteria with twisted or spiral shape
vibrios
comma shaped bacteria
obligate aerboes
organisms that need oxygen for respiration
envelope
coat outside a virus derived from lipids in the host cell
capsid
protein coat of a virus
capsomeres
repeating protein units that make up capsid in virus cell
virus attachment particles
antigens that target proteins in host cells surface membrane
Dna viruses
composed of dna as genetic material
rna viruses
composed of rna as genetic material
retroviruses
special type of rna virus that controls the production of dna corresponding to viral rna and insert it into the host cell dna
reverse transcriptase
enzyme synthesised in the life cycle of a retrovirus that makes dna corresponding to viral rna genome
non virulent
micro organism that doesnt cause disease
provirus
dna thats inserted into host cell during lysogenic pathway of production of viruses
lysogeny
period when cell virus doesnt effect host
latent
state of non virulent cell within host cell
ebola
highly infectious disease that causes fever and internal bleeding and death in half cases
mortality rate
measurment of the number of deaths in a given population or due to a specific case
pandemic
epidemic that takes place in several places or globally
mitosis
process by which a cell divides and produces two daughter cells
asexual re produces
geneticlly indentical produce
meiosis
gametes making sexually different organisms
histones
positively charged proteins involved in coiling of dna to form dense chromosomes in cell division
nucleososomes
dense clusters of dna wound around histones
karyotype
way of displaying images of chromosomes of a cell to show pairs of autosomes and gametes
cell cycle
regulates process in which two daughter cells are produced
interphase
period between active cell division when cells increase their size and mass replicate dna and are in normal stage
chromatid
one strand of dna joined with other chromatids in centrosomes
cyclins
small proteins that vuild up during interphase and involved in control of cell cycle by their attachment to cyclin dependent kinases
cyclin dependent kinases
enzymes involved in control of the cell cycle by phospholyrating other proteins activated by atatchment to cyclins
prophase
first stage of cell division where chromosomes are coiled up and consist of the daughter chromatids joined by the centromere. the nucleoluus breaks down
metaphase
second stage of active division where a spindle of overlapping protein microtubules form and chromatids line up on the metaphase plate
anaphase
third stage
where centromeres split so chromatids become new chromosomes.
moved to opposite sides
centromeres first
by contractions of microtubules of spindles
telophase
where nuclear membrane forms around two sets of chromosomes
chromosomes unravel and spindle breaks down
centromere
region where a pair of chromatids joined which attached to single strand of spindle at metaphase plate
metaphase plate
region of spindle in middle of cell where chromosomes line up
cytokenesis
division of cytoplasm to make two daughter cells
clones
genetically identical offspring produced as a result of natural or artificial asexual reproduction
binary fission
splitting of one individual to form other individuals
sporulation
production of asexual spores that can grow into individuals
regeneration
use of mitosis to regrow a body part that has been lost
fragmentation
use of mitosis to regenerate whole organism with fragment of an animal
budding
outgrowth from parent organism which develops into individual via mitosis
vegetative propogation
a plant forms a structure by mitosis that develops into a fully differentiated genetically identical new plant
parthenogenesis
an unfertilised egg develops into a new individual
dry mass
mass of an organism where all water is removed from
meristem
region of mitosis and growth in a plants shoot or root
diploid
cell with nucleus containing full set of chromosomes
haploid
cell with once complete set of chromosomes
zygote
cell formed when to haploid cells fuse at fertilisation
fertilisation
fusing of two haploid cells to form diploid zygote
polypoidy
when cell or organism has more than two sets of organisms
gonads
sex organs in animals
anthers
sex organs in plants
pollen
produced in anthers
has haploid male gametes in plants
ovules
formed in overies
have haploid female gametes in plants
testes
male sexual organs
spermatoza
haploid male gamates in animals
ova
haploid female gamates in animals
microspores
result of meiosis in plants that produce male gametes pollen
megaspores
result of meoisis in plants that produce female gametes in plantes ovula
chiasmata
points where chromosomes break during recombination
translocation
part of chromosome breaks of and joins different chromosome
sex chromosomes
with haploid nucleus that determine sex of offspring
non disjunction
when chromosomes fail to seperate and copy so one has copy and one doesnt
monosomy
when only one member of pair of chromosome present in cell
polysomy
when cell contains three or more of same chromosome
aneuploidy
when cell has to many or few chromosomes
mutation rate
rate at which mutation naturally occurs
mutagens
chemicals known to increase rate of mutation
gameotegenesis
formation of gametes in sex organs
primordial germ cell
cells that divide by meosis do form sperm and ova
spermatogenesis
formulation of sperm in testes
oogenesis
formulation of ova in ovaries
sporophyte generation
diploid generation in plants that produce spores by meiosis
gametophyte generation
haploid generation in plants that gives rise to gametes by mitosis
sporophyte
diploid main body of plant
pollen sacs
parts of anthers where pollen grains develop
tube nucleus
male nucleus where that will control production of pollen tube in fertilisation
generative nucleus
male nucleus that will fuse with female nucleus
pollen tube
tube that grows out of pollen grain down style into ovary and through micropyle of ovule to carry two male nuclei to the ovule
placenta
pad of special tissue that attaches plant ovule to the ovary wall
pollination
transfer of pollen from anther to stigma
external fertilisation
process of fertilisation of female gamete by male gamete met outside parental bodies to fuse and fertilise
internal fertilisation
fertlisation of female by male inside mothers body
acrosome
region of head that has enzymes to digest layer of ova
zona pelludica
layer of protective jelly around infertilused egg cell
polyspermy
fertilisation of egg by more than one sperm
fertilisation membrane
tough layer formed outside egg to stop more sperm getting in
conception
fertilisation of sperm in humans
germination
pollen tube start to grown out of pollen grains to transfer male nuclei to ovule
double fertilisation
one male nucleus fuses with nuclei of two polar nuclei to form endosperm nucleus and fuses with egg cell to form diploid zygote
totipotent
cell is able to develop into any type of cell
cleavage
special type of mitosis with no interphase to have lots of undifferentiated cells
blastocyst
hollow ball of cells 5 days after fertilisation
embryonic stem cells
cells in early stage embryo that have potential to form many other cells
pluripotent
cell is able to develop into most other cells
pluripotent embryonic stem cells
cells that can form most but not all types of cells
cell determination
pedestination of cells to become type of tissue depending on position
diffrentiate
develop into specific type of tissues