Topic 1 – Key Concepts in Biology-Cells And Microscopy Flashcards
state the two types of cell
eukaryotic (animals and plants) and prokaryotic
what is difference between eurkaryotic and prokaryotic?
eukaryotic cell contains nucleus and membrane bound organelles. a prokaryotic bound organelle
list components of both plants and animals
nucleus cytoplasm cell membrane mitochondria ribosomes
how is genetic information stored in eukaryotic cell
within nucleus arranged in chromsomes
other then storing genetic information, what is the function of the nucleus?
controls cellular activites
describe structure of cytoplasm
fluid component of cell
contain organelles enzymes dissolved ions and nutrients
what is function of cell membrane
controls entry and exit of materials into and out of the cells
what is the function of the mitochondria
sits of later stages of aerobic respiration in which ATP (Energy) is produced
what is function of ribosomes
joins amino acids in a specific order during translation
what organelles are found in plant cells only
large permanent vacuole
cell wall
chloroplasts
what is cell wall made off
celluose
what is function of cell wall?
provide strength
provide cell bursting when water enters by osmosis
what does permanent vacuole contain?
solution of salts, sugars and organic acids
what is function of permanent vacuole?
supporting cell, maintain its turgidity
what is function of chlorplasts
site of photosynthsis
when looking at a cell using light microscope why are chloroplasts green?
contain chlorophyll a green pigment
list organelles found in prokaryotic cells
chromosomal DNA Plasmid DNA Cell wall Cell membrane ribosomes flagella
how is genetic information stored in prokaryotic cell?
found free within cytoplasm as:
chromosomal DNA
plasmid DNA
What are plasmids?
small circular loops of DNA found free in cytoplasm and separate from main DNA
carry genes that provide genetic advantages e.g. antibiotic resistance
what is the prokaryotic cell wall composed of?
peptidoglycan
what is a flagellum
long rotating whip like protrusion, enables bacteria to move
what is a haploid cell
cell contains single copy of each chromosome, 23 chromosomes in humans
what are gamates
reproductive cells, haploid cells
describe sexual reproduction in terms of chromosome number?
2 haploid gametes fuse
resulting embryo has 2 chromosomes for each gene and 2 copies of each allele dipolid
describe how egg cells are adapted to their function
haploid nucleus contains genetic material
mitochondria in cytoplasm produce energy for developing embryo
cytoplasm contain nutrients for developing embryo
cell membrane hardens after fertilisation, preventing entry of other sperm, ensuring zygote is diploid
describe how sperm cells are adapted to their function
haploid nucleus contain genetic information
tail enable movement
mitochondria provide energy for tail movement
acrosome contain enzymes that digest egg cell membrane
where are ciliated epithelial found?
found lining the surface of structures such as respiratory tract and uterus.
describe function of ciliated epithelial cells lining the airway
move in synchronised waves to beat mucus (dirt and pathogens) up to the back of throat where it can be swallowed.
what is magnification
numbers of time bigger an image appears compared to size of speciman
how can total magnification of an image be found from lens power?
total magnification= eyepiece lens magnification x objective lens magnification
how can the magnification of an image be calculated?
size of image/size of specimen
what is resolution?
smallest distance between 2 objects that can be distinguished
how does a light microscope work?
passes beam of light through specimen which travel through eyepiece lens, allowing specimen to be observed.
what are advantages of light microscopes?
inexpensive
easy to use
portable
observe both dead and living organisms
what is disadvantage of light microscopes?
limited resolution
how does an electron microscope work?
uses beam of electrons which focused using magnets. electrons hit fluorescent screen which emits visible light, producing an image.
name 2 types of electrons
transmission electron microscope (TEM)
scanning electron microscope (SEM)
what is advantage of electron microscope?
greater magnification and resolution
why do electron microscopes have greater have greater resolution and magnification?
use a beam of electrons which has shorter wavelength than photons of light
how have electron microscopes enabled scientists to develop understanding of cells?
allow small sub cellular structures to be observed in detail
enable scientists to develop more accurate explanations about how cell structure relates to function
what are disadvantages of electron microscope?
expensive
large so less portable
requires training to use
only dead specimens can be observed.
how do you convert m to mm?
x10^3
how do you convert m to um
x10^6
how do you convert m to nm?
x10^9
how do you convert from m to pm?
x10^12
write 0.005 in standard form
5x10^-3
