Cell Structure Flashcards
What is the cell?
The basic unit of structure and function in the living organism
Differences between animal and plant cells
Cell walls vs no cell wall
Large vacuoles vs small temporary vacuoles
Chloroplasts vs no chloroplasts
Cell ultrastructure
The structure of a cell as seen with an electron microscope
other name for cell membrane
plasma membrane
what is the cell membrane?
a very thin boundary around the cell
what is the cell membrane composed of?
phospholipids and proteins
where is the phosphate in the phospholipid bilayer
the heads
where are the lipids in the phospholipid bilayer
the tails
hydrophilic part of phospholipid bilayer
phosphate
hydrophobic part of phospholipid bilayer
lipid
4 functions of the cell membrane
retains the cell contents
selectively permeable barrier
has receptor sites
displays antigens
what is the benefit of the cell membrane being a semi permeable barrier
allows some molecules to pass through and prevents others
what are the receptor sites in the cell membrane for?
for binding with molecules such as hormones
what are antigens
molecules that stimulate the formation of antibodies
what is the cytoplasm?
watery cell contents that surround the nucleus
what percentage of the cytoplasm in human cells is made up of water
70-90%
3 functions of the cytoplasm
supports and separates the organelles
acts as a storage area eg. for food and salt
chemical reactions occur in it
1 example of a chemical reaction that occurs in the cytoplasm
glycolysis in respiration
cytosol
liquid part of the cytoplasm
cytoplasm without the organelles
when do you say cytosol instead of cytoplasm
only when asked for it
what is the largest cell organelle
the nucleus
what surrounds the nucleus?
a nuclear membrane
what type of membrane is the nuclear membrane?
a double membrane
what does the nucleus contain?
the chromosomes
what are chromosomes composed of?
DNA and protein
when are chromosomes visible
when they are dividing
what happens to the chromosomes between the divisions
they become uncoiled and form a tagles mass called chromatin
3 functions of the nucleus
controls cell structure and function
DNA replication and nuclear division
controls the formation of mRNA
what is the formation of mRNA called
transcription
describe the nuclear membrane
a double lipo-protein membrane with pores
2 functions of the nuclear membrane
retains the nuclear contents
has pores to allow materials in and out of the nucleus
What is a ribosome
a very small organelle
what are ribosomes made of
RNA and protein
RNA
ribonucleic acid
function of ribosomes
protein synthesis
Describe the miochondrias appearance
a rod-shaped organelle with 2 membranes
outer layer of the mitochondria
outer membrane
inner layer of the mitochondria
inner membrane
what is on the inner membrane of the mitochondria
cristae
the middle of the mitochondria
the matrix
Function of the mitochondria
aerobic respiration
what is aerobic respiration
the release of energy from food that needs oxygen
what does the number of mitochondria in a cell relate to?
the energy requirements of that cell
cells that need a lot of energy
have a large number of mitochondria
what is the cell wall composed of?
cellulose
is the cell wall permeable at all
yes, fully permeable
3 fucntions of the cell wall
gives shape to the cekk
prevents plants from bursting
protects against pathogens
why is it important for the cell to have good shape?
gives shape to the whole plant
how does the cell wall prevent the plant from bursting
when water is taken in by osmosis it allows the development of turgor
what is the large vacuole
a sac surrounded by a membrane
what is the large vacuole filled with
fluid called cell sap
3 functions of the large vacuole
stores water
stores food
holds gases
why is it important for the vacuole to store water
to make the cell turgid
what food does the vacoule store?
sugar, salt, protein, amino acids etc.
what gases are held in the vacuole
O2 CO2
describe the chloroplast
a green oval-shaped organelle that contains chlorophyll
function of the chloroplasts
photosynthesis
what is photosynthesis
the making of food using sunlight energy
2 types of cells
prokaryotic and eukaryotic cells
2 things that prokaryotic cells dont have
a nucleus
membrane bound organis
2 membrane bound organelles
mitochondria and chloroplasts
which kingdom do the prokaryotes belong to?
The kingdom monera (bacteria)
which kingdoma do the eukaryotes belong to?
protoctista, fungi, plant and animal
with what unit are cells measured?
micrometers
top part of the microscope
eyepiece
what hold the objective lens in place
the nose piece
what magnifies the image a lot
objective lens
low power lens strength
x10
high power lens strength
x40
what focuses the image
coarse and fine focus adjustment wheels
where do you put the slide
on the stage
what adjusts the amount of light passing through the slide
iris diaphragm
what illuminates the object
mirror/light bulb
what is passed up through the specimen
visible (white) light
what do the lenses do?
they bend the light so that the image appears magnified
how do you find total magnification
by multiplying the powers of the lenses
what is the first thing you do when using a microscope
switch on the lamp
which lens do you use first?
the low power lens
what do you put on the stage of the microscope?
a prepared slide
what do you use the coarse adjustment focus wheel with?
the low power lens
what do you use the fine adjustment focus wheel with?
the high power lens
what do you swab your cheek with?
a disposable loop
what do u cover the sample with 2
drop of water or methelene blue
2 reasons for the cover slip
stop the specimen from drying out
protect the lens
how do you lower the cover slip
slowly
at 45º angle
why do you lower the cover slip at 45º angle
so as not to trap any air bubbles
what plant cell do you use
an onion
what part of onion do you use
the inner epidermis
which stain do you use on a plant cell
iodine
