From big to small - 3rd form Flashcards
1
Q
what is the function of the nucleus
A
-controls the activity of the cell
-contains the chromosomes which carry the genes
2
Q
what is the function of the cell membrane
A
-boundary between the cytoplasm and the cell’s surroundings
-controls what substances enter and leave the cell (selectively permeable)
3
Q
what is the function of the cytoplasm
A
jelly-like liquid where chemical reactions occur
4
Q
what is the function of the mitochondria
A
-carries out some reactions of aerobic respiration, producing ATP
5
Q
what is the function of the ribosomes
A
-synthesise proteins from amino acids
6
Q
what is the function of the chloroplasts
A
-absorb light energy and use it to carry out the chemical reactions of photosynthesis, making biological molecules for plant cells
7
Q
what is the function of the cell wall
A
- made of cellulose in plants
- helps to keep plant cells in a fixed shape
8
Q
what is the function of the vacuole
A
- filled with a watery liquid called cell sap
- stores dissolved sugars, mineral ions, and other substances
9
Q
symbol for millimetres
A
mm
10
Q
symbol for micrometres
A
um
11
Q
symbol for nanometres
A
nm
12
Q
how many millimetres in a metre
A
1x10^3 (1 thousand)mm in 1m
13
Q
how many micrometres in a metre
A
1x10^6 (1 million)mm in 1m
14
Q
how many nanometres in a metre
A
1x10^9 (1 billion)mm in 1m
15
Q
how do you calculate magnification
A
size of image/actual size of object
size of image/magnification
actual size of object x magnification
16
Q
what are cells
A
the smallest functional unit of life and contain a number of organelles, structures that carry out specific processes the cells need to survive
17
Q
what are the different types of cells that have specific jobs called
A
specialised cells
18
Q
what are tissues
A
groups of similar cells, which work together to carry out the same function
19
Q
what are organs
A
made up of several different tissues working together to carry out a more complex function
20
Q
what are organ systems
A
made up of several different organs working together to carry out a complex function essential to life
21
Q
what is the function of red blood cells
A
transport oxygen in the blood
22
Q
what are the features of red blood cells
A
- contains the protein haemoglobin which binds to and transports oxygen
- no nucleus which means there is more space for haemoglobin
- biconcave shaped which means there is a larger surface area meaning oxygen can enter and leave the cell more rapidly
23
Q
what is the function of a sperm cell
A
to transport male genetic material to the egg cell
24
Q
what are the features of a sperm cell
A
- the flagellum (tail) allows the sperm to swim
- many mitochondria provide the energy needed for swimming
- the acrosome (package of enzymes) to digest the jelly layer surrounding the egg cell
25
what is the function of a palisade (leaf) cell
to carry out photosynthesis
26
what are the features of a palisade (leaf) cell
- many chloroplasts which trap light energy for photosynthesis
- tall and thin meaning cells can pack tightly together so more of the light reaching the leaf is absorbed
27
what elements are carbohydrates made from
carbon, hydrogen and oxygen
28
what is the function of carbohydrates
used as fuel for respiration
29
what chemical reaction are carbohydrates broken down in
respiration
30
what are the smallest units of carbohydrates
simple sugars (glucose and fructose)
31
examples of complex carbohydrates
starch and glycogen
32
what is the function of starch
used to store glucose in plants
33
what is the function of glycogen
used to store glucose in animals and fungi
34
why are starch and glycogen better storage molecules
they are less soluble that simple sugars and so have less effect on water movement in and out of cells
35
what elements are lipids (fats) made from
carbon, hydrogen and oxygen
36
what are the smaller units of lipids
3 fatty acids and a glycerol molecule
37
what are the many functions of lipids (fats)
-energy storage (can also be used in respiration)
- part of cell membranes
- thermal insulation
-electrical insulation (around nerve cells)
- buoyancy (helps marine animals like whales to float)
38
what elements are proteins made from
carbon, hydrogen, oxygen and nitrogen
39
what are the smaller units of proteins
amino acids
40
what are the main functions of protein in the body
- structural molecules
- controlling chemical reactions
- messenger molecules such as hormones
- combating disease with antibodies
- transport
41
what is the test for glucose
Benedict's solution
42
how do you carry out Benedict's solution test
1. add Benedict's solution to a sample of food (in solution)
2. place in water bath at 80 degrees C for 5 minutes
3. if a reducing sugar is present the colour will change from blue to brick red + if it is green, yellow, or orange it is still a positive result but will have a lower concentration
43
what is the test for starch
Iodine
44
how do you carry out the iodine test
1. add a few drops of orange iodine solution to the sample on a spotting tile
2. a blue-black colour indicates the presence of starch
45
what is the test for protein
Biuret
46
how do you carry out the biuret test
1. add 2cm^3 of water to a food sample and shake (if not already liquid)
2. add an equal volume of dilute potassium hydroxide and shake
3. add two drops of 1% copper sulfate solution
4. if protein is present then a pale purple colour will develop
47
what is the test for lipids
Emulsion
48
how do you carry out the emulsion test
1. the food sample is placed in a test tube
2. add a small volume of absolute ethanol and shake to dissolve any lipid in the alcohol
3. add an equal volume of water
4. a cloudy white colour (caused by emulsion forming) indicates the presence of lipid
49
what are enzymes
biological catalysts which increase the rate of a reaction without being used up itself in the reaction
50
what is a catalyst
a chemical which increases the rate of reaction without being used up itself in the reaction
51
what is the lock and key theory
- the substrate and enzyme collide
- the substrate binds to the active site of the enzyme
- binding to the active site strains the chemical bonds in the substrate molecules meaning the reaction occurs by an alternative pathway with a lower activation energy
- once the reaction has occurred the products do not fit the active site's shape as well as the substrate did so the products are released
- after the reaction the enzyme molecule is free to catalyse the next reaction
52
what is special about the active site of an enzyme
the active site of a particular enzyme has a specific shape which is complimentary to the shape of the substrate(s) which means that each enzyme can only catalyse one reaction
53
what affects the rate of an enzyme controlled reaction
temperature, changes of pH, adding more substrate or enzyme
54
how does temperature affect the rate of an enzyme controlled reaction
as temperature increases, the enzyme and substrate have more kinetic energy, meaning they move faster and so there are more successful collisions
55
how is an enzyme denatured
all proteins are held together by forces between different parts of the amino acid chain. high temperatures and changes of pH disrupt these forces, so the shape changes meaning the protein is denatures because in enzymes, the active site changes shape so it is no longer complimentary to the substrate
56
what is the affect of adding more substrate or enzyme in an enzyme controlled reaction
adding more substrate or enzyme is increasing the concentration so it will speed up the reaction
57
what temperature do enzymes usually become denature over
40 degrees C
58
what is a genome
a genome is the total DNA of an organism - coding for all its characteristics
59
what is a gene
a gene is a short section of DNA within a chromosome - it codes for a specific protein (which gives us characteristics)
60
what is a chromosome
a chromosome is a straight (linear) strand of DNA.most cells contain pairs of chromosomes (two strands with the same genes)
61
what is DNA
DNA is the chemical which contains the information for making proteins - it contains the instructions for all the structures and reactions needed in all the cells of an organism
DNA is a double stranded molecule, made of two chains of nucleotides. the strands coil to form a double helix
62
what is a nucleotide
a nucleotide is formed of a sugar, a phosphate and a nitrogenous base
63
what are the four bases of DNA
Adenine
Thymine
Cytosine
Guanine
64
what do the bases form
the bases form complimentary pairs which join the two sugar-phosphate backbones together
65
which bases pair with each other
Adenine always pairs with Thymine
Cystosine always pairs with Guanine
66
what does the sequence of triplets of bases provide
it provides instructions for the sequence of amino acids in a protein
67
what are the five kingdoms
plants, animals, fungi, protoctista and bacteria
68
what are eukaryotes
- eukaryotes are organisms whose cells contain a proper nucleus (a membrane sphere containing linear chromosomes of DNA)
- they also have other organelles with outer membranes such as mitochondria
69
are plants multicellular or single celled
all multicellular - made of many (specialised) cells
70
how do plants get food
they make their own complex biological molecules by photosynthesis
71
plant cell adaptations
cell have chloroplasts for photosynthesis
cellulose cell wall
72
what do plants store carbohydrates as
starch or sucrose
73
are animals multicellular or single celled
all multicellular - made of many (specialised) cells
74
how do animals get food
eat other living things to obtain nutrients (biological molecules)
75
animal cell adaptations
do not have chloroplasts or a cell wall
76
what do animals store carbohydrates as
glycogen
77
why do animals have a nervous system
for coordination and movement
78
is fungi multicellular or single celled
many are multicellular - they consist of threads of cells called hyphae and the whole structure is called a mycelium
79
examples of fungi with a reproductive structure
mushroom or toadstool
80
how do fungi get their food
saprotrophic nutrition
81
adaptations of fungi cells
no chloroplasts
chitin cell wall
many nuclei per (large) cell
82
what do fungi store carbohydrates as
glycogen
83
example of single celled fungi
yeast
84
example of multicellular fungi
mucor - typical hyphal structure
85
is protoctista multicellular or single celled
all single celled
86
how do protoctista get their food
some photosynthesise, others feed on living organisms or organic remains
87
protoctista cell adaptations
cells can have:
-chloroplasts - for photosynthesis
- cell wall
- flagella for movement
88
examples of protoctista and how they feed
amoeba - feed on other living organisms
chlorella - photosynthetic
89
which protoctista causes malaria
plasmodium
90
what are bacteria
small, single-celled organisms
91
what are prokaryotes
they do not have a proper nucleus
92
what happens to the genetic material of bacteria
the genetic material is in the cytoplasm in the form of a single circular chromosome
93
bacteria cells structure
all bacteria cells:
- cell membrane which controls what enters and leaves
- cell wall made made of peptidoglycan which maintains shape and protects the cell
- cytoplasm containing the circular chromosome where chemical reactions occur
many also have:
- a slime capsule outside the cell wall providing more protection
- plasmids, small circles of DNA containing extra genes
- a flagellum which allows bacteria to move
94
what are pathogens
microoragnisms which cause infectious diseases
they harm the host by releasing toxins or damaging cells
95
what things can be pathogens
all viruses are pathogens
bacteria, fungi and protoctista can also be pathogens
96
what are viruses
a strand or genetic material surrounded by a protein coat
97
are viruses cells
n, they are not alive - they do not respire, pr carry out any of the other normal processes taking place in living organisms
98
how do viruses reproduce
they have to enter a host cell - they take over the ribsosomes and enzymes in the cell to make new virus particles
99
what are decomposers
(fungi and some bacteria) feed by saprotrophic nutrition
100
how do decomposers feed
they secrete digestive enzymes outside of their cells onto the dead organism
the dead organism is broken down into small, soluble molecules which are then absorbed by the decomposer
