Cell Structure Flashcards
(112 cards)
1
Q
What is magnification?
A
The number of times bigger the image or drawing is compared to the real size
2
Q
What is resolution?
A
The minimum distance needed to differentiate between 2 separate objects
3
Q
Whats the equation for magnification?
A
Image/actual size
4
Q
How many um in a mm?
A
1000
5
Q
How many nm make up 3 um?
A
3000
6
Q
What is cell fractionation?
A
The separation of individual organelles
7
Q
What is homogenisation?
A
The first stage of fractionation, where cells are broken open by a homogeniser
8
Q
What is used to break up cells in fractionation?
A
Homogeniser
9
Q
What is ultracentrifugation?
A
Where fragments of homogenate are separated into organelles
10
Q
Why is a buffer solution used in cell fractionation?
A
To keep the pH from changing, so proteins aren’t denatured
11
Q
Why is an isotonic solution used in cell fractionation?
A
To prevent osmosis, so organelles don’t burst or shrink
12
Q
Why should an ice cold solution be used in cell fractionation?
A
To reduce enzyme activity so organelles aren’t destroyed
13
Q
In cell fractionation, what order are organelles separated?
A
Nuclei
Mitochondria
Lysosomes
Ribosomes
14
Q
Why is the homogenate filtered in cell fractionation?
A
To remove any complete cells or large debris
15
Q
What is a graticule?
A
A glass disc with a scale that is placed in the eyepiece of a microscope
16
Q
What are the 2 steps in using a graticule?
A
1)measure length of object with graticule
2) calibrate against a stage micrometer
17
Q
What is cell ultrastructure?
A
The submicroscopic structure of cells and organelles
18
Q
What is the function of a cell wall?
A
To strengthen plant cells
19
Q
Whats a cell wall made out of?
A
Cellulose fibres
20
Q
Whats the largest organelle?
A
Nuclei
21
Q
What are the features of a nucleus membrane?
A
Double membrane, has pores to allow materials in and out of the
22
Q
What organelle is attached to the nucleus?
A
Endoplasmic reticulum
23
Q
Where are chloroplasts found?
A
In plant tissue’s palisade mesophyll layer
24
Q
What is stroma?
A
Fluid inside chloroplasts that contain enzymes for photosynthesis
25
Where are grana found?
Chloroplasts
26
In mitochondria, what are the folds called?
Cristae
27
What is made in cristae?
ATP
28
What is the inside of the mitochondria called?
The matrix
29
What does the mitochondria matrix contain?
Ribosomes, DNA loop
30
Where does aerobic respiration occur in a cell?
Mitochondria
31
What is the function of ribosomes?
The site of protein synthesis, found in huge numbers
32
What is the RER?
Rough endoplasmic reticulum
33
Whats the function of RER?
To package and transport proteins
34
Whats the function of SER?
To produce lipids
35
What is pinched off of the Golgi body?
Vesicles - small pieces of RER
36
Whats the function of the golgibody?
To package lipids and proteins
37
What organelles do prokaryotic cells contain?
Flagellum, cytoplasm, membrane, cell wall, plamid, capsule, genetic material
38
What’s the function of a flagellum?
Allows bacteria to move, like a tail
39
What are bacterial cell walls made of?
Murein
40
What’s a plasmid?
A tiny circle of DNA carrying a few genes
41
What is a virus?
A type of pathogen that needs a host cell to survive
42
What organelles do viruses have?
Cytoplasm, capsid, nucleic acids
43
What is differentiation?
When cells become specialised for particular functions
44
What are cells that differentiate in the same way called?
Tissues
45
What is epithelial tissue?
Tissue found in animals that line the surface of organs for protection
46
What is xylem tissue?
Tissue found in plants, used to transport water and ions
47
what’s the function of the vacuole
maintains pressure within the cell as it is filled with cell sap
48
what’s the structure and function of chloroplasts?
made of stacks of grana, that contain chlorophyll for photosynthesis. Chloroplasts are where photosynthesis occurs
49
what’s the structure and function of the cell wall?
In plants, the cell wall is made of cellulose and provides strength to prevent the cell from bursting
50
What’s the function and structure of the RER?
transports proteins, has sheets called cisternae and has ribosomes present on the surface
51
What’s the function and structure of SER?
Similar to RER, but doesn’t have ribosomes on the surface. Stores and transports both lipids and carbohydrates
52
What’s the structure and function of nucleus?
Has a double membrane (nuclear envelope), and pores to let molecules out of the nucleus. It holds genetic information and controls the actions of the cell
53
What’s the structure and function of mitochondria?
Has an inner membrane folds called cristae, and then the matrix makes up the inside of mitochondria. It’s the site of aerobic respiration in cells.
54
What’s the function of lysosomes?
Break down pathogens and waste material
55
What’s the structure and function of ribosomes?
very small organelles found in the cytoplasm, the site of protein synthesis
56
Order the units of measurement from largest to smallest
km, m,cm,mm,um,nm
57
How do you convert nanometers to micrometers?
divide by 1000
58
How do you convert micrometers to millimetres?
Divide by 1000
59
How do you convert millimeters to micrometers?
times by 1000
60
How do you convert micrometers to nanometers ?
times by 1000
61
How would you express 0.03mm in standard form?
3x10 to the power of -2
62
What are the structural differences between prokaryotic cells and eukaryotic cells?
Prokaryotic cells do not have a nucleus, whereas eukaryotic cells do
Prokaryotic cells do not have membrane bound organelles, but eukaryotic cells do
63
What’s an example of eukaryotic cells?
Human and plant cells
64
What type of cell is prokaryotic?
Bacteria cells
65
Describe how living things are organised?
Organelles,cells,tissues,organs,organ systems, organisms
66
How are red blood cells adapted for their function?
Biconcave shape increases surface area, contain haemoglobin, no nucleus so more room for oxygen, thin membrane
67
How are sperm cells adapted to their function?
Have a tail which allows for movement, mitochondria to provide energy for tail, streamlined design
68
How are root hair cells adapted to their function?
Large surface area to absorb more water, no chloroplasts as they are underground, thin walls so water intake is efficient
69
How are neurons adapted to their function?
Mylen sheath insulates the impulses so they travel faster, branched connections to allow them to connect across the body
70
How are epithelial cells adapted to their function?
they have cilia that help to move substances in one direction
71
how are xylem cells adapted to their structure?
hollow and allowing water to travel through
72
what’s an disadvantage of an electron microscope?
can’t see in colour, can’t see living specimens, very expensive
73
what are the advantages of light microscopes?
cheaper, easy to use, can see in colour, can see living specimens
74
What are disadvantages of light microscopes?
low resolution (0.2um) , max magnification of 1500x
75
what’s the link between wavelength and resolution?
the longer the wavelength, the lower the resolution and the further away 2 objects have to be to distinguish
76
How does a light microscope work?
light passes through the specimen, through the lenses and into the eye of the observer
77
Why are stains used in microscopy?
they help to see specimens better
78
how does an tem electron microscope work?
-an electron beam is projected through a sample
-in dense parts, electrons are easily absorbed
-this makes them appear darker
79
what are limitations of tems?
must be performed in a vacuum, only used for thin tissue
80
how does a sem microscope work?
-electrons are projected across a specimen
-the beam is passed back and forth
81
What’s the role of a capsid in a virus?
a layer of protein that protects the genetic material of the virus
82
What’s the role of attachment proteins in viruses?
Attachment proteins (glycoproteins) help viruses bind to host cells
83
What’s the structure of virus particles?
They have an envelope, genetic material, glycoproteins, capsid
84
What’s the purpose of a plasmid?
carry genes for dna replication
85
what’s the purpose of a capsule?
protects the bacterium, helps groups of bacteria stick together
86
how is the structure of a virus related to replication within cells?
the attachment proteins help to attach to host cells, they also have nucleic acids that can multiply inside host cells
87
What organelle can be found in the lowest spin during ultracentrifigulation?
nucleus
88
What organelles can be found in the fastest spin speed?
ribosomes and lysosomes
89
What is a microscope artefact?
a detail that is caused by the process of preparing a specimen, like air bubbles
90
How are microscope artefacts formed?
incorrect sample preparation, or dust on the sample
91
In mitosis, how many daughter cells are produced?
2
92
In mitosis, is there any variation in the daughter cells?
no, they are genetically identical
93
What’s the chromosome number of daughter cells?
46
94
what’s the function of mitosis?
Growth, replacement of dead cells, asexual reproduction
95
What are the phases of mitosis?
Prophase, metaphase, anaphase, telophase
96
What occurs in prophase?
Chromosomes begin to become visible as they are thicker and shorter,centrioles move to the poles of the cells and produce spindle fibers, the nucleus disappears and the envelop breaks down
97
What occurs in metaphase?
Chromosomes line up at the equator of the cell, each chromosome attaches to the spindle fibers through the centromere
98
What occurs in anaphase?
the centromere divides, separating the chromatids, chromatids are pulled by spindle fibers to the poles of the cell, chromatids are pulled by the centromere first
99
What occurs in telophase?
chromatids reach the poles of the cell where they uncoil to become long and thin, a nuclear envelope begins to form around each group
100
What occurs in cytokinesis?
The centre of the cell behind to pinch to divide into 2 cells, and the cytoplasm divides forming 2 genetically identical daughter cells
101
What is binary fission?
The process of cell division in prokaryotic cells
102
What organisms carry out binary fission?
prokaryotes like bacteria
103
Describe the sequence of events by which viruses replicate?
-attach to the host cell
-inject nucleic acid into the host cell
-genetic info provides instructions for the host cell’s metabolic processes
104
Why are viruses difficult to treat?
they are extremely small, and surrounded by a protective coating
105
How do cancer treatments inhibit stages of the cell cycle?
Chemotherapy prevents DNA replication, and prevents metaphase as spindle fibers aren’t produced
106
How is cancer formed?
through growth disorders in the cell, as a result of damage to genes that regulate mitosis
107
What are the stages of the cell cycle?
Interphase, nuclear division and cytokinesis
108
What are the stages of interphase?
M,G1,S, G2
109
What occurs during the G1 phase of interphase?
rapid growth, cells synthesise new organelles
110
what occurs in the G2 phase?
centrioles replicate and micro tubules construct spindle fibers
111
What’s the cell cycle?
the sequence of events in which cells divide
112
Why do some cells in multicellular organisms not follow the cell cycle?
some do not have the ability to divide
