pack 1 - cells Flashcards
(42 cards)
1
Q
what do all cells contain
A
- cell surface membrane
- cytoplasm
- genetic material
2
Q
how do prokaryotes form new cells
A
- binary fission
3
Q
dna - pro
A
-short circular molecule of DNA not associated with protein and free in the cytoplasm
- carries genetic codes for protein
4
Q
cell wall - pro
A
- contains murein a glycoprotein
- prevents osmoticlysis, rigid, strengthening
5
Q
cytoplasm - pro
A
- solution where many dissolved molecules are found
- site of many metabolic reactions
6
Q
cell surface membrane - pro
A
- phospholipid bilayer with embedded proteins
- controls passage of substrates across exchange surfaces by passive or active transport
7
Q
small ribosomes 70s - pro
A
- small structures in the cytoplasm
- protein synthesis
8
Q
simple flagellum - pro
A
- thin rotating fibre
- responsible for movement of cell
9
Q
plasmids - pro
A
- one or more small loops of DNA can replicate independently
- can pass genetic info via conjugation to other bacteria
10
Q
capsule - pro
A
- extra layer outside cell wall
- protects from dessiccation onagocytosis and some pathogens
11
Q
plasma membrane - euk
A
- membrane found on cell surface and most internal organelles. made of a phospholipid bilayer which has embedded proteins
- selectively permeable allows cell identification
12
Q
nucleus - euk
A
- contains chromosomes which are long, linear DNA molecules associated with histone protein. surrounded by nuclear envelope, with nuclear pores. has one or more nucleoli
- DNA contains genetic code for making proteins
- nucleolus manufactures ribosomes
13
Q
mitochondrion - euk
A
- oval shaped organelle surrounded by 2 membranes inner membrane folded and forms cristae. fluid inside called matrix. contains circular DNA like that in pro
- produces ATP from aerobic respiration. ATP is th energy store used by cells for processes such as active transport and protein synthesis
14
Q
rough endoplasmid reticulum - euk
A
- a series of tubes in the cytoplasm of cell. appears rough due to ribosomes attached to membranes
- synthesis and transport of protein through cytoplasm
15
Q
ribosomes 80s - euk
A
- small organelle made of RNA and protein, not surrounded by a membrane
- protein synthesis
16
Q
smooth er - euk
A
a series of tubes in the cytoplasm of cell
- synthesises and transports lipids
17
Q
golgi apparatus and vesicles - euk
A
- stack flattened sacs. vesicles continually bud off from the ends of these sacs
- modifies and processes proteins that are made in the cell and packages them into vesicles ready for export from the cell (exocyrosis)
- forms lysosomes
18
Q
lysosomes - euk
A
- golgi vesicles contains hyrolytic enzymes sometimes known as lysozymes
- digest unwanted material in the cell
19
Q
cell wall - plant
A
- made of cellulose - this provides high tensile strength that prevents osmotic lysis
20
Q
vacuole - plant
A
- filled with cell sap - gives rigidity
21
Q
fungi cell wall made of
A
chitin
22
Q
envelope - chloroplast
A
- a double- membrane surrounding the chloroplast
23
Q
granum - chloroplast
A
- s stack of membrane bound discs called thylakoids. the thylakoids membrane contain chlorophyll- the membrane provide a large surface area for light absorption
24
Q
stroma - chloroplast
A
- contains enzymes needed for photosynthesis and stores starch grains
25
DNA - chloroplast
- short, circular and not associated with proteins
26
tissue
- a group of similar cells
- muscle
27
organ
- a group of tissues
- heart
28
organ system
- a group of interacting organs forming a complex functional whole
29
what are viruses and how do they divide
- not cells and so non living
- acellular
- cannot undergo cell division, attach to and enter a host cell and use their machinery to replicate
30
what are the components of a virus
- genetic material- either DNA or RNA
- capsid - a protein coat
- attachment protein - allow the virus to attach to a host cell
31
definition of magnification
the number of times bigger the image appears compared to its actual size
32
definition of resolution
- minimum distance between 2 objects at which they can be seen as separate
33
optical microscope
- optical microscopes use light to illuminate the specimen, and glass lenses are used to focus the light
- there is an eyepiece lens of fixed magnification and a selection of objective lenses of various magnifications
- specimens must be thin enough to transmit the light
- light has a relatively long wave length and so the resolution is low
34
electron microscopes
- the electron microscope uses a beam of electrons, which are focused using series of electromagnets
- electrons have a much smaller wavelength than light so the resolution is higher
35
transmission electron microscopes
- the beam of electrons is transmitted through the specimen. the specimen must be very thin
- the greater the resolution means that smaller organelles such as ribosomes can be observed, as well as internal detail of organelles
- higher resolution than SEM
- no 3d images
- allows details of internal cell structures to be seen
36
scanning electron microscopes
- can be used to study 3d objects. the electrons that are reflected off the surface of the object rather than passing through it
37
converting between mm- nm
mm *1000 um *1000 nm
38
magnification
i = a*m
39
eyepiece graticule
- the eye piece graticule scale is first calibrated against a stage micrometer scale to work out the length that each eyepiece graticule division represents at a particular magnification
- the eye piece graticule scale can then be used to measure an object under the microscope
40
cell fractionation
- cells are broken open using a homogeniser, this breaks cell membrane and allows the organelles to be released
- cell debris and whole cells are filtered off to leave a suspension
41
ultracentrifugation
- the resultant suspension is centrifuged at a low speed
- the most dense organelles, the nucleus, separates at the bottom of the tube. the rest of the organelles are still suspended in the supernatant
- the supernatant is poured into a fresh tube and spun at a higher speed to separate off the mitochondria
- the process is repeated at increasing speeds to separate off the less dense organelles. a very high speed will be need to separate out ribosomes
42
conditions during the separation
cold temp- reduces enzyme activity so no digestion of organelles
buffer - maintains constant pH to prevent denaturation of enzymes
isotonic - same water potential as organelles to prevent osmotic lysis
