cell structure Flashcards
cells:
single nerve cell- branching, receives signals from up to 100,000 other nerve cells.
paramecium- this protozoan is a single giant cell, can swim by beating the cilia that cover its surface, often lives in stagnant warm water, can eat pathogenic fungi cryptococcus neoforms.
chlamydomonas- can be found all over the world in soil, fresh water, oceans, snow on top of moutains. photosynthetic, swims with flagella.
saccharomyces cerevisiae- yeast cell, used for baking bread. reproduces by budding cells- cells divide quickly.
helicobacter pylori- bacteria, causes stomach ulcers, uses a handful of whip like flagella to propel itself through stomach lining.
3 shapes of cells:
spherical cells.
rod shaped cells.
spiral cells
human epithelial cells:
epithelial cells cover the inner and outer body cavities, such as the stomach and urinary tract.
can exist in multiple layers for protection.
epithelia can specialise to act as sensory receptors. they form taste buds, line the nose, ear and eye.
female reproductive organs are lined with ciliated epithelial cells.
the skin is made of epithelial cells. its striated layers demonstrate the extensive morphology of epithelia.
epithelia is the first type of cell to differentiate in the embryo. this occurs during the cell cycle.
epithelia can change appearance depending on location.
epithelial uses in forensics:
a person sheds about 400,000 skin cells per day.
can be recovered from clothes, weapon and other objects.
DNA from these cells needs to be isolated and matched to a victim or suspect.
fingerprints:
stratified layer of cells.
undulation of the ridges and furrows produce fingerprints, palm prints and sole prints.
chemical composition can change with aging. proteins, lipids (fats/oils), water, inorganic, ions.
cells in the fundamental unit of life:
epithelial cells- form protective barriers in tissues. may be specialised to absorb or secrete specific compounds.
muscle cells- responsible for movement of skeleton, heart, many internal organs.
nerve cells- conduct electrical signals throughout the body. control contraction of muscles. responsible for the 5 senses.
connective tissue cells- create extracellular material that holds together in tissue. may be specialised to absorb or resist external forces. plant cells- share most structures and functions with animal cells. can be highly specialised in different plant types.
prokaryotic cells: are single celled organisms, each capable of performing all functions to live and reproduce. lack internal membrane bound components (organelles) but have complex structural organisation.
lividity:
lividity refers to the bluish purple discolouration of skin after death. it is a common sign associated with lovor mortis
waters unusual traits:
other molecules of similar size (ch4 and co2) are gasses at room temp.
water is a polar molecule. ch4 and co2 do not have partially charged atoms and therefore do not form hydrogen bonds.
when liquid water is cooled enough to form a solid, the solid water is less dense, so ice floats on liquid water, if liquid ch4 and co2 were cooled enough to form solids, these solids would sink to the bottom of the liquid phase.
water has a very high specific heat and is a good thermal insulator. it takes more heat energy to raise the temp of water than is needed to raise the temp of ch4 and co2.
carbon can form 4 covalent bonds
carbon monoxide:
CO diffuses rapidly into the blood after entering through the lungs. co causes hypoxia through the formation of cohb and a leftward shift of oxyhaemoglobin dissociation curve and the binding to heame containing proteins, particularly cytochrome c oxidase and myoglobin.
amino acids are polymers containing amino and carboxylic acid groups:
protein building blocks. central carbon bound to amino and carboxylic acid groups plus hydrogen R groups. R group side chain differs for each aa. aa linked together by peptide bonds to form proteins.
nucleotides contain a sugar, a phosphate group and a base:
building block for DNA and RNA. RNA=ribose. DNA= deoxyribose. phosphate groups attach to 5’ carbon. base attaches to 1’ carbon.
cells contain distinct structures that perform specialised:
