Topic 1 - Key concepts in biology Flashcards
1
Q
what are all living things made up of?
A
cells
2
Q
what are eukaryotic cells like
A
complex and includes all plant and animal cells
3
Q
define eukaryote
A
organism that are made up of eukaryotic cells
4
Q
what are prokaryotic cells like
A
smaller and simpler e.g. bacteria
5
Q
define prokaryote
A
is a prokaryotic cell (it is a single-celled organism)
6
Q
define cytoplasm
A
jelly-like liquid that fills cell and contain enzymes where most of the cell’s reaction takes place
7
Q
define cell membrane
A
- surrounds all cells and are made of lipids
- very thin, flexible and partially permeable
- controls what can enter and leave the cell
8
Q
define nucleus
A
- contains genetic material DNA
- controls cell’s activities by making enzymes and other proteins
9
Q
define mitochondria
A
- small sausage shaped organelles which contain enzymes for aerobic respiration
- where aerobic respiration takes place
10
Q
define flagellum
A
- long protein strand that can rotate
11
Q
define vacuole
A
- large membrane sac containing dilute mineral solutions called cell sap
- keeps plant cell firm or turgid
12
Q
define cholorplast
A
- contains green chlorophyll to absorb light energy
- where photosynthesis takes place
13
Q
define chromosomal DNA
A
- circular DNA within cytoplasm not within the nucleus
- controls the cell
14
Q
define plasmid DNA
A
- small loops of extra DNA that contains genes
- offers resistance to certain drugs
15
Q
define cell wall
A
- strong, rigid wall made of cellulose in plants
- fully permeable
- supports the cell and strengthens it
16
Q
define ribosomes
A
- small and lots of them
- place where proteins are made through translation
17
Q
define specialised cells
A
made through a process called differentiation
18
Q
define stem cells
A
cells that have the ability to differentiate into specific cell types
19
Q
define magnification
A
how big an image is compared to the object size
20
Q
define resolution
A
smallest separation at which two separate objects can be distinguished or resolved
21
Q
what are the 2 types of microscopes?
A
light microscope
electron microscope
22
Q
what are the limitations of light microscopes?
A
- lower resolution
- lower magnification
23
Q
what are the benefits of light microscopes?
A
- easier
- cheaper
- images can be viewed in colour
24
Q
what are the benefits of an electron microscope?
A
- higher resolution
- higher magnification
25
what are the limitations of an electron microscope?
- very large
- cannot view live samples
- images are viewed in black and white
- expensive
26
what are the adaptations of red blood cells?
- large surface area
- no nucleus
- contains haemoglobin
- biconcave disc shape
27
why are red blood cells adapted to have no nucleus?
room for more oxygen that helps the body to be oxygenated
28
why are red blood cells adapted to have a biconcave disc shape?
makes a larger surface area that helps carry oxygen for the lungs
29
what are the adaptations of a nerve cell?
- can have longer axon lengths
- dendrites with receptor proteins
- has a myelin seath
30
why are nerve cells adapted to have longer axon lengths?
helps increase the speed of electrical impulses being close to each other
31
why are nerve cells adapted to have dendrites with receptor proteins?
when receiving it after a synapse the receptors bind to the neurotransmitters to generate a new impulse
32
why are nerve cells adapted to have a myelin sheath?
insulates the electrical impulses to make sure that it can go quicker
33
what are the adaptations of a root hair cell?
- hair like projections
- lots of mitochondrion
- large surface area
34
why are root hair cells adapted to have hair like projections?
allows more active transport of mineral ions so the plant can have as much as possible
35
why are root hair cells adapted to have lots of mitochondrion?
releases energy from glucose during respiration to provide energy for active transport
36
why are root hair cells adapted to have large surface area?
take up water and mineral ions to increase the rate of absorption
37
what are the adaptations of palisade cells?
- column shaped and arranged closely together
- packed with many chloroplasts
38
why are palisade cells adapted to have many chloroplasts?
maximises the absorption of light for photosynthesis
39
why are palisade cells adapted to be arranged closely together?
they are densely packed at the top of the leaf to access more sunlight
40
what are the adaptations of muscle cells?
- they have multiple nuclei
- contains filament of proteins
41
why are muscle cells adapted to contain lots of mitochondrion?
provides energy for contractions and responses
42
define diffusion
net movement of particles from an area of high concentration to low concentration
43
in which states can diffusion happen?
liquid
gas
44
why can diffusion happen in liquid and gas?
because the particles are free to move about
45
what is the criteria for diffusion thru membranes?
only very small molecules can diffuse thru the membrane, big molecules like starch and proteins can't fit thru the membrane
46
define osmosis
net movement of water molecules across a partially permeable membrane from a higher region of water to a lower one
47
what directions do water molecules pass thru the membrane and why?
pass both ways, due to the random movement of them
48
why does osmosis go from high to low?
due to more water molecules being on one side there is a steady flow of water into the region of fewer molecules
49
define active transport
movement of particles across a membrane against a concentration gradient using energy transferred during respiration
50
what is the formula for surface area to volume ratio?
surface area / volume
50
what does it mean if there is a bigger surface area to volume ratio?
the better it is at diffusing
51
define enzyme
-biological catalyst
-made up of proteins in a 3D shape
52
what 4 things is the effectiveness of an exchange surface increased by?
-large surface area
-efficient blood supply
-thin membrane to provide a short diffusion path
-ventilation
53
what happens to an animal cell in an dilute solution?
net diffusion of water into the cell so the cell bursts
54
what happens to an animal cell in an concentrated solution?
net diffusion of water out of the cell so the cell shrinks
55
what happens to an plant cell in an dilute solution?
net diffusion of water into the cell so the cell becomes turgid
56
what happens to an plant cell in an concentrated solution?
net diffusion of water out of the cell so cytoplasm shrinks out of cell wall and the cell plasmolysis
57
what is the water concentration like in a dilute solution?
high
58
what is the water concentration like in a concentrated solution?
low
59
what 3 factors that can affect the rate of diffusion?
concentration
temperature
surface area
60
why is there a rise in the rate of reaction of enzymes in high temps?
there are more successful collisions as molecules have more energy
61
why is there a peak in the rate of reaction of enzymes at the optimum temp?
at this point they have the right amount of energy to collide and react
62
why is there a fall in the rate of reaction of enzymes in high temps?
there is too much energy that the bonds break and the enzyme becomes denatured
63
what does it mean when cell membranes are 'partially permeable'?
small molecules can go thru them but big molecules cant
64
describe a method for the osmosis practical with potatoes
-add 30 cm^2 water of sugar solution to a boiling tube
-repeat this with equal volumes of diff concentrations of sugar solution
-use water to give a concentration of 0.0
-cute potato bits of equal size
-weigh each piece and place one in each tube
-remove the pieces form the solutions after 24 hours
-dry each potato cylinder with a paper towel
65
