chapter 2 basic components of living systems Flashcards
what organelles are in animal cells?
cell membrane, cytoplasm, centrioles, RER, SER, golgi apparatus, lysosomes, mitochondria, nucleus, ribosomes.
what organelles are in plant cells?
cell membrane, cell wall, cytoplasm, chloroplasts, RER, SER, golgi apparatus, mitochondria, nucleus, ribosomes, permanent vacuole, possibly lysosomes
what organelles are in prokaryotic cells?
cell membrane, cell wall, cytoplasm, ribosomes, free floating DNA, plasmids
what is the function of the cell membrane?
controls what enters and exits the cell (important for homeostasis)
what is the function of the cell wall?
important for cell structure and shape also provides additional protection
what is the function of the cytoplasm?
site of chemical reactions, has cytosol (jelly) and cytoskeleton supporting organelles.
what is the function of the centrioles?
come from the centrosome, involved with cell division and spindle fibres. positions flagella and cilia.
what is the function of chloroplasts?
involved in photosynthesis
what is the structure and function of the SER/RER?
has many folds, helps materials get around cell and processes molecules.
RER- has ribosomes to make proteins
SER- makes lipids/steroids and involved in detoxification
what is the function of the golgi apparatus?
assembles items sent from ER, modifies, sorts and packages materials for delivery
what is the function of the lysosome?
contains enzymes to break down and digest substances
what is the function of the mitochondria?
makes ATP, is the cellular respiration site.
what is function of the nucleus?
contains genetic material, controls cell activities
what is the function of ribosomes?
makes proteins
what is the function of vacuoles?
stores material depending on cell type
what are the 3 components of the cytoskeleton?
microtubules(tubulin), microfilaments (actin), intermediate filaments
what parts of the cytoskeleton are found in eukaryotes and prokaryotes?
eukaryotic- all 3
prokaryotic- microtubule, microfilaments
what is the functions of the cytoskeleton?
helps keep cell’s shape, can actively contract allowing cells to migrate, allow organelles to move around inside the cell, cell division (spindle fibres)
how many lenses does a compound light microscope have?
2
what are the different types of slide preparation?
dry mount, wet mount, squash slides, smear slides
what is a wet mount?
specimens suspended in liquid and a cover slip is placed on top.
what is a dry mount?
solid specimens are cut into thin pieces and a cover slip is placed on top
what is a squash slide?
wet mount is prepared then a slide is used to gently press down the cover slip to squash the specimen
what is a smear slide?
edge of a slide is used to smear the specimen onto another slide
Why are stains used when viewing cells under a microscope?
many cell structures are transparent so stains increase contrast which allows organelles to become more visible
What do crystal violet and methylene blue do?
they are positively charged dyes so attract the negatively charged cytoplasm leading to staining of organelles
what do nigrosin and congo red do?
they are negatively charged dyes and are repelled by negatively charged cytosol therefore staining the outside of the cells leaving the cells unstained making them more visible.
what is the calculation for magnification?
size of image/actual size
what is the limiting factor in light microscopy?
resolution and lenses increase magnification but it will become too blurred at a point
How do TEMs work?
a beam of electrons is transmitted through a specimen and focused to produce an image
what is the resolution of a TEM?
~0.5nm
how does an SEM work? what images does it produce?
beam of electrons are sent across the surface of the specimen and reflected electrons are collected. it produces 3D surface images of the specimen
what is the resolution of an SEM?
3-10nm
Give an advantage and a disadvantage of light microscopes.
easy to operate and cheaper, images produced in colour. only up to 2000x magnification, 200nm resolution
Give an advantage and a disadvantage of electron microscopes.
500,000x magnification, very high resolution. vacuum is required and very expensive/hard to operate
what is an artifact?
visible structural detail caused by processing the specimen rather than being a feature of a specimen
what is a laser scanning confocal microscope? and where is it used?
a microscope that employs a laser beam and a pin hole aperture to produce an image with very high resolution. it is used to diagnose eye diseases
what are atomic force microscopes?
type of scanning microscope that uses a mechanical probe to ‘feel’ a specimen’s surface. resolution of 0.1nm
what is the structure of the nucleus?
It has a double membrane called a nuclear envelope which surrounds DNA protecting it. Nuclear pores are present to allow molecules to move in and out of the nucleus.
what is the function of the nucleolus?
area within the nucleus responsible for producing ribosomes
what are flagella and cilia?
flagella is an extension used to enable cell mobility and sometimes detects chemical changes in the cell’s environment. cilia are important in sensory organs like the nose. each cilium contains 2 central microtubules surrounded by 9 other microtubules referred to as the 9+2 arrangement
explain how proteins are synthesised and produced.
•the nucleolus forms ribosomes which can be free floating or attached to the RER.
•proteins are synthesised on ribosomes bound to the RER
•they then pass into the cisternae of the RER and are packaged into vesicles
•these vesicles travel to the golgi apparatus along the cytoskeleton
•they fuse with the cis face of the golgi body and proteins enter
•proteins are structurally modified and packaged into vesicles and leave via the trans face
•secretory vesicles travel to the cell membrane and fuse with it releasing their contents via exocytosis
•some vesicles form lysosomes containing enzymes used in the cell.
