SAC 1 Flashcards
Plasma membranes, proteins, enzymes and energy transformations. (95 cards)
1
Q
Unicellular
A
Consisting of one cell
2
Q
Multicellular
A
Composed of many cells
3
Q
Autotrophs
A
Manufacture their own food
4
Q
Heterotrophs
A
Rely on other sources for food
5
Q
Organic chemicals
A
Complex carbon-containing molecules
6
Q
Inorganic molecules
A
Do not contain carbon in a complex form Eg water co2 o2 minerals such as cl-, k+, mg2+
7
Q
Ionic bonds
A
Occur between ions, particles that have an electrical charge
Pos and neg charges attract
Eg Na+ are attracted to Cl- to form NaCl
8
Q
Covalent Bonds
A
Bonds in which atoms share electrons
Polar or non polar
H20 is polar
Ch4 (methane) is non polar
9
Q
Hydrogen bonds
A
formed by the attraction between polar molecules
Not very strong
Eg liquid water is held together by hydrogen bonds between H and O atoms in water molecules
10
Q
Biomacromolecules
A
Proteins
Carbohydrates
Nucleic Acids
Lipids
11
Q
What are polymers made up of?
A
Many monomers
12
Q
Why are lipids different?
A
They rarely form polymers
13
Q
Condensation reaction
A
Water is released
Building larger molecules
Forming polymers
14
Q
Prokaryotic cells
A
smallest living cells diameters of 0.5 to 1.0 micrometres have a cell membrane and cytosol lack membrane bound organelles have no nuclear membrane have just one circular chromosome
15
Q
Plasmids
A
small circular units of DNA
16
Q
Fimbriae
A
hairline structures used for attachment
17
Q
cell wall in a prokaryote
A
made of a polysaccharide
18
Q
capsule
A
protects bacteria
19
Q
flagellum
A
used for movement
20
Q
Simple base molecule of carbohydrates
A
monosaccharides
21
Q
Simple base molecule of proteins
A
amino acids
22
Q
Simple base molecule of nucleic acids
A
nucleotides
23
Q
Simple base molecule of lipids
A
fatty acid
steroids
24
Q
Carbohydrates
A
carbon hydrogen oxygen important as an energy supply some are important in structural support
25
Proteins
```
carbon
hydrogen
oxygen
nitrogen
some contain sulfur
```
26
nucleic acids
```
carbon
hydrogen
oxygen
nitrogen
phosphorous
DNA or RNA
```
27
DNA stands for
deoxyribonucleic acid
28
RNA stands for
ribonucleic acid
29
Lipids
```
carbon
hydrogen
oxygen
may contain phosphorous and nitrogen
insoluble in water (hydrophobic)
do not form polymers
```
30
monosaccharides
most important of which is glucose
others include fructose, galactose and ribose
monosaccharides contain rings of carbon atoms bonded covalently to oxygen and hydrogen atoms
31
amino acids
20 commonly found in proteins
contain and amino group (NH2) and a carboxylic acid group (COOH)
Basic structure is the same, R group varies in each of the 20 amino acids
32
nucleotides
nitrogenous base
| phosphate group and 6-C sugar (deoxyribose or ribose) alternating backbone
33
Starch
branched chains of glucose molecules used as a storage molecule in plants
34
glycogen
branched chains of glucose molecules used as a storage molecule in animals
the chains are more branched than those in starch
35
cellulose
also composed of glucose molecules
| it forms plant cell walls
36
chitin
forms the basis of insect exoskeletons, and the cell walls of some fungi.
composed of chains of modified glucose molecules
37
peptides and polypeptides
chains of amino acids
| individual amino acids are held together by peptide bonds
38
protein
is one or more polypeptides coiled or folded into a specific shape
39
fibrous proteins
important for cellular structure
40
globular proteins
include important molecules such as haemoglobin, all of the enzymes and protein hormones
41
DNA
double stranded helix shaped molecule
main constituent of chromosomes
the molecules backbones are held together by covalent bonds between the sugar and phosphate groups
two strands of DNA are held together by hydrogen bonds between the bases
42
RNA
single stranded molecule
43
Fats
composed of three fatty acid and glycerol
fats and oils are long term energy storage molecules
insoluble in water
phospholipids are the major component of cell membranes
44
how big are eukaryotic cells
10um to 100um (micrometer)
45
eukaryotic cells
membrane bound organelles suspended in cytosol
have a distinct double layered nuclear membrane
have many linear chromosomes
46
light microscope magnification
x400
47
cell membrane description
double layer of phospholipids embedded with protein molecules, glycoproteins and some short carbohydrate chains
48
cell membrane function
encloses all cell contents
regulates the movement of materials into and out of the cell
helps to maintain shape
communicates with neighbouring cells
49
nucleus description
it is surrounded by a double membrane and is usually large compared to other organelles
contains chromosomes and the nucleolous
50
nucleus function
information in the chromosomes controls the production of proteins in the cell
these proteins, in turn, control cellular functions
51
mitochondria description
sacs made up of two membranes
the inner membrane is folded to create cristae, increasing surface area
the cristae enclose the fluid-filled matrix
52
mitochondria function
site of aerobic respiration, they are responsible for most of the cell's energy production
most abundant in cells with high energy needs eg muscle cells and cells of the kidney tubule
53
ribosome description
small spherical bodies composed of RNA and protein
54
ribosome function
site of protein synthesis
55
smooth endoplasmic reticulum description
a network of membranes that create channels in the cytoplasm from the nucleus to the cell membrane
56
smooth endoplasmic reticulum function
site of lipid synthesis and transport of many materials throughout the cell
abundant in cells that produce steroid hormones
57
rough endoplasmic reticulum description
a network of membranes that create channels in the cytoplasm
rough ER is studded with ribosomes
58
rough endoplasmic reticulum function
transports and folds proteins produced by ribosomes
synthesises glycoproteins
parts of the ER pinch off to become vesicles for transport of proteins to the membrane or to other organelles, including the golgi bodies
59
golgi complex description
stacks of flattened membrane sacs
60
golgi complex function
packages proteins and glycoproteins into vesicles for secretion from the cell or to be sent to other organelles
modifies some proteins and glycoproteins
synthesises cellulose in plant cells
abundant in cells that export cell products
61
lysosome description
a membrane sack containing many digestive enzymes
62
lysosome function
contains enzymes that digest ingested materials and wastes
| important in programmed cell death
63
vacuole description
a membrane bound sac containing fluid, sugars and ions
| appears as a clear area when seen through a microscope
64
vacuole function
important in turgor in plant cells; the pressure of fluid in the large vacuole helps maintain cell shape
also used for storage of sugars, ions and food
65
chloroplast description
surrounded by a double membrane, contains stacks of membranes (grana) embedded in less dense membrane and fluid (stroma)
66
chloroplast function
the site of photosynthesis; grana (or thylakoid membranes) contain chlorophyll, the pigment that traps light energy
abundant in leaf cells
67
centriole description
a pair of cylindrical structures made up of several smaller tubes
68
centriole function
the spindle forms between centrioles during cell division
69
flagella or cilia function
provides movement of the cell or fluid surrounding the cell
70
cell wall description
a layer of cellulose (in plants) secreted by the cell and completely surrounding the cell membrane
71
cell wall function
provides structural support and defines the shape of cells
72
hydro phillic
water loving
| molecules that have an affinity with water and are able to form hydrogen bonds with water molecules
73
hydro phobic
water hating
repel water molecules
insoluble in water
74
exocytosis
movement of materials out of a cell via a vesicle. vesicle fuses with the plasma membrane, and the vesicle contents are released out of the cell
75
endocytosis
the process in which a cell takes in a substance or particle from outside the cell by engulfing it within the plasma membrane to form a vesicle, bringing it into the cell
76
integral protein
protein that is partially or fully embedded within the plasma membrane
77
peripheral protein
a type of protein attached to the outer surface of the phospholipids or the integral proteins in the plasma membrane
they do not penetrate the hydrophobic centre of the hydrophobic plasma membrane
78
glycoprotein
carbohydrate chain attached to protein
| act as cell surface markers
79
cholesterol
assists with membrane fluidity and structure
80
carrier protein/ protein pump
transport proteins that have a specific shape complementing certain molecules
when they bind, the protein changes shape and delivers the molecule through the membrane
eg glucose and amino acids
81
channel protein
hydrophillic passageways that facilitate the diffusion of large or polar molecules
82
solute
molecule that is dissolved into the solution
83
solvent
the substance (liquid) that in which the solutes are dissolved to form a solution
84
solution
a mixture that typically consists of one or more solutes dissolved and distributed throughout a solvent
85
How does molecular size affect permeability?
smaller molecules are able to cross the plasma membrane a lot easier than larger molecules (diffuse using no energy)
86
How does presence of net charge affect permeability?
molecules with a neutral charge (non-polar, lipophillic) can cross easier than charged molecules
87
How does temperature affect permeability?
cold temperatures reduce membrane fluidity, decreasing permeability
high temperatures can denature the membrane and proteins
88
How does pH affect permeability?
pH levels that aren't optimal for the cell can denature the membrane and proteins
89
diffusion
the passive net movement of molecules across a semi permeable membrane from a region of high solute concentration to a low solute concentration (along concentration gradient)
90
facilitated diffusion
the passive net movement of molecules across a semi permeable membrane from a region of high solute concentration to a low solute concentration via transport proteins
allows larger, and/or charged molecules to move across the plasma membrane through a channel or carrier protein
91
osmosis
net movement of water molecules across a semi permeable membrane from a region of high water (low solute/high solvent) concentration to low water (high solute/low solvent) concentration
92
role of integral proteins
```
transport systems eg protein channels
enzyme function
signal transduction
cell-cell recognition
inter cellular joining
attachment to the cytoskeleton and extracellular matrix
```
93
role of peripheral proteins
```
function as enzymes
receptors
structural attachment points
cellular recognition points
```
94
why is the plasma membrane described as a mosaic
the way that specialised proteins are variously embedded in the plasma membrane gives it a mosaic look from above due to the uniform background of phospholipids
95
substances that can easily pass through plasma membrane
lipid soluble substances eg alcohol
small uncharged molecules eg water (aquaporins)
small molecules eg o2, co2
