year 10 mocs year 9 work Flashcards
1
Q
what are all living things made of
A
cells
2
Q
what are eukaryotic cells like
A
complex and include all animal and plant cells
3
Q
what are prokaryotic cells like
A
smaller and simpler e.g. bacteria
4
Q
what are eukaryotes
A
organisms made of eukaryotic cells
5
Q
what is a prokaryote
A
a prokaryotic cell (a single-celled organism)
6
Q
what are subcellular structures
A
what the different parts of a cell are called
7
Q
what subcellular structures do animal cells have
A
nucleus, cytoplasm, cell membrane, mitochondria, ribosomes
8
Q
what does a nucleus contain
A
genetic material that controls the activities of the cell
9
Q
what is genetic material in the nucleus arranged into
A
chromosomes
10
Q
what is cytoplasm
A
a gel-like substance where most of the chemical reactions happen, it contains enzymes that control these reactions
11
Q
what is a cell membrane
A
holds the cell together and controls what goes in and out
12
Q
what are mitochondria
A
where most of the reactions for respiration take place
13
Q
what are ribosomes
A
involved in translation of genetic material in the synthesis of proteins
14
Q
what subcellular structures do plant cells have
A
nucleus, cytoplasm, cell membrane, mitochondria, ribosomes, rigid cell wall, large vacuole, chloroplasts
15
Q
what is a rigid cell wall made of
A
cellulose
16
Q
what does a rigid cell wall do
A
supports and strengthens the cell
17
Q
what does a large vacuole do
A
contains cell sap, a weak solution of sugar and salts
maintains internal pressure to support cell
18
Q
what are chloroplasts
A
where photosynthesis occurs-makes food for plant
contain green substance; chlorophyll
19
Q
what subcellular structure do bacteria cells not have
A
a nucleus
20
Q
what subcellular structures do bacterial cells have
A
chromosomal DNA, ribosomes, cell membrane, plasmid DNA, flagellum
21
Q
what does chromosomal DNA do
A
controls cells activities and replication
it floats free in cytoplasm
22
Q
what is plasmid DNA
A
small loops of extra DNA that aren’t part of chromosome
contain genes for drug resistance- can be passed between bacteria
23
Q
what is a flagellum
A
long hair like structure that rotates to make bacteria move. can be used to move bacteria away from harmful substances (toxins) and towards oxygen and nutrients
24
Q
what are specialised cells
A
cells with a structure that makes them adapted to their function
25
what are egg and sperm cells specialised for
reproduction
26
why are the sperm and egg cell nuclei called 'haploid'
because both nuclei only contain half the number of chromosomes that's in a normal body cell
27
why is an egg cell adapted with nutrients in the cytoplasm
feed embryo
28
why does the membrane of an egg cell change structure after fertilisation
to stop any more sperm getting in- makes sure offspring have the correct amount of DNA
29
what are the main functions of an egg
to carry female DNA and nourish developing embryo in early stages
30
what is the function of a sperm
transport males DNA to females egg
31
how is the nucleus of an egg and sperm cell adapted
haploid nucleus
32
why are sperm cells adapted with long tails
so it can swim to egg
33
why are sperm cells adapted with lots of mitochondria
to provide energy (from respiration) to swim to the egg
34
why are sperm cells adapted with an acrosome at the front of their 'head'
it stores enzymes used to digest through membrane of egg cell
35
what are ciliated epithelial cells specialised for
moving materials
36
how do ciliated epithelial cells move substances in one direction along the surface of the tissue
they beat
37
why do the lining of the airways contain lots of ciliated epithelial cells
help move mucus up to throat so it can be swallowed and doesn't reach lungs
38
what do microscopes use to magnify images
lenses and increase resolution of image
39
what does resolution mean
how well a microscope distinguishes between two points that are close together
40
how do light microscopes work
work by passing light through a specimen
41
how do electron microscopes work
use electrons rather than light to pass through a specimen
42
why are electron microscopes much better than light ones
higher magnification and resolution
43
what are advantages of the higher magnification and resolution of electron microscopes
see smaller things in more detail e.g internal structure of mitochondria and chloroplasts
44
viewing specimen with light microscope
| why do you need to first put one drop of water on your slide
secure specimen
45
viewing specimen with light microscope
| why do you need to add a drop of stain if your specimen is colourless or transparent
makes specimen easier to see
| different stains highlight different structures within cells e.g. methylene blue stains DNA
46
viewing specimen with light microscope
| what do you need to do after you have stained your sample
place a cover slip over it
47
viewing specimen with light microscope
| after the slide is clipped onto the stage, which lens should you use
lowest powered objective lens
48
viewing specimen with light microscope
| after you have selected the lowest powered lens, what should the coarse adjustment nob be used to do
move stage up, so slide is underneath objective lens and then move stage down until the specimen is nearly in focus
49
viewing specimen with light microscope
| for the last step, what should you use to adjust the focus
fine adjustment nob until image is clear
50
what is the smaller nob on a microscope called
fine adjustment nob
51
what is the bigger nob on a microscope called
coarse adjustment nob
52
what are the lenses on a microscope called
high and low power objective lenses
53
what is the platform on which the sample is placed called
stage
54
what are the clips on a microscope used to do
secure the sample
55
what is the bit on a microscope that you look through called
eyepiece lens
56
what is magnification
how many times bigger the image is
57
what is the formula for total magnification
eyepiece lens magnification x objective lens magnification
58
what formula can be used to find total magnification without knowing lens magnification (formula triangle)
image size
-----------------------------
magnification x real size
59
what is a millimetre in standard form
x 10 to the power of -3m
60
what is a micrometre in standard form
x 10 to the power of -6m
61
what is a nanometre in standard form
x 10 to the power of -9m
62
what is a picometre in standard form
x 10 to the power of -12m
63
what are enzymes
act as biological catalysts, produced by living things
64
what can reduce the need for such high temperatures and speed up the useful chemical reactions in the body
enzymes
65
what is a catalyst
a substance that increases a reactions speed, without being used up or changed in the reaction
66
why do enzymes have specialised shapes
so they can catalyse reactions
67
what is the substrate
the molecule that is changed in the reaction
68
what is an enzymes active site
the part where it joins on to its substrate to catalyse the reaction
69
what is the ''lock and key'' mechanism
for enzyme to work, substrate must fit into active site, but if if substrate shape doesn't match then the reaction wont be catalysed
70
why is it bad if the temperature for an enzyme catalysed reaction gets too hot
some of the bonds holding the enzyme together break and this changes the shape of the enzymes active site, so substrate wont fit. Enzyme is denatured
71
what is the name for the temperature that enzymes work best at
optimum temperature
72
why do enzymes have an optimum temp
kinetic energy in substrate and enzyme molecules is ideal for the maximum number of collisions
73
how does the Ph being too low/high affect enzymes
interferes with the binds holding enzyme together- changes active site shape, and denatures enzyme
74
what is often the optimum Ph of an enzyme
pH7
75
how does substrate concentration affect rate of reaction
higher substrate concentration = faster reaction
76
why does rate of reaction increase as substrate concentration increases
because it is more likely that the enzyme will meet up with and react with a substrate molecule
77
why does increasing substrate concentration only increase rate of reaction up to a point
all active sites of enzymes are full
78
which enzyme catalyses the breakdown of starch to maltose
amylase
79
what solution can be used used to detect if starch is present
iodine solution
80
what colour will the iodine solution change if starch is present
go from browny/orange to blue/black
81
give 3 examples of big molecules
proteins, lipids and some carbohydrates
82
why is it important that organisms can break down bigger molecules into smaller components
so they can be used for growth and other life processes
83
what organism stores energy in the form of starch
plants
84
what do enzymes do when plants need energy
break down starch into smaller molecules (sugars)- can be respired to transfer energy - used by cells
85
what does the enzyme carbohydrase convert
carbohydrates into simple sugars
86
what is an example of a carbohydrase, and what does it break down from and into
amylase, breaks down starch to maltose and other sugars e.g. dextrins
87
what does the enzymes proteases convert
proteins into amino acids
88
what does the enzymes lipases convert
lipids into glycerol and fatty acids
89
what will happen to the ph of a solution when lipids are broken down
fatty acids will lower the pH of solution they are in
90
what can break down big molecules, as well as join molecules together
enzymes
91
why are digestive molecules broken down by enzymes
break them down so that they aren't too big to pass from the intestine to the blood
92
what does synthesise mean
to construct a larger biological molecule from smaller ones
93
where are carbohydrase enzymes produced
mouth (in saliva), pancreas and small intestine
94
examples of proteins
haemoglobin, collagen and keratin
95
where are protease enzymes produced
stomach, pancreas and small intestine
96
what are lipids
large molecules made from small units of fatty acids and glycerol
97
where are lipase enzymes produced
pancreas and small intestine
98
how can carbohydrates be synthesised
joining together simple sugars
99
what is glycogen synthase
an enzyme that joins together lots of chains of glucose molecules to make glycogen (molecule used to store energy in animals)
100
what are proteins made by
| and what do enzymes have to do with this
joining amino acids together
| enzymes catalyse the reaction
101
what is the synthesis of lipids from
fatty acids and glycerol
102
what are the 3 ways substances can move in and out of cells
diffusion, osmosis and active transport
103
definition of diffusion
net (overall) movement of particles from an area of high concentration to an area of lower concentration
104
what type of molecules can diffuse through cell membranes
very small molecules
105
examples of small molecules that can fit through cell membranes
glucose, amino acids, water and oxygen
106
why does diffusion happen in liquids and gases
because the particles are free to move
107
what is osmosis
diffusion of water molecules from an area of high to low concentration through a partially permeable membrane
108
what is a partially permeable membrane
one with very small holes, so it only allows water and small molecules to pass through it, but not larger ones e.g. starch
109
why do water molecules pass both ways through the membrane during osmosis
because water molecules move about randomly all the time
110
when the concentration of water is the same on both sides of the membrane what will the movement of water molecules be like
same in both directions
| will be no net movement of water molecules
111
how will water move into cells with partially permeable membranes
osmosis
112
what is active transport
movement of particles across a membrane against a concentration gradient (i.e. low- high concentration) by using energy transferred during respiration
113
what will happen if there's a lower concentration of nutrients in the gut than in the blood
active transport allows nutrients into the blood - essential to stop us starving
114
what is an experiment to investigate osmosis
| and explain what results show
put pieces of potato in beakers with different concentrations of sucrose solution, measure mass before and after
if the potato gains mass, then water concentration was higher outside than in, so water was drawn in by osmosis
if mass stays the same then water concentration insidide potato cylinder and the sucrose solution has stayed the same
if mass decreases , water in sucrose solution is lower than in potato cylinders, so they lose water
115
what are chromosomes
coiled up lengths of DNA molecules
116
what happens in mitosis
makes two cells, identical to original cell, the nucleus of each new cell contains same no. of chromosomes as original cell
117
what do body cells in multicellular organisms do in the cell cycle
divide to produce new cells
118
what is the stage of the cell cycle where the cell divides
mitosis
119
what do multicellular organisms use mitosis to do
grow or replace damaged cells
120
what is it called when some organisms use mitosis to reproduce
asexual reproduction
121
what are the stages of the cell cycle
```
-interphase
four stages of mitosis:
prophase
metaphase
anaphase
telophase
and after mitosis there is cytokinesis
```
122
what happens in interphase
cell grows to increase no. of mitochondria and ribosomes
| then duplicates its dna, copied dna forms x shaped chromosomes
123
what is prophase
chromosomes condense- get shorter and fatter
| membrane around nucleus breaks down and chromosomes lie free in cytoplasm
124
what happens in metaphase
chromosomes line up at centre of cell
125
what happens in anaphase
cell fibres pull chromosomes apart
| two arms of each chromosome go to opposite ends of the cell
126
what happens in telophase
membranes form around each set of chromosomes, these become nuclei of two new cells- nucleus has divided
127
what happens in cytokenisis
before telophase ends, cytoplasm and cell membrane divide to form two separate cells
128
what are the new cells produced after mitosis called
daughter cells
129
what are daughter cells and why
genetically identical diploid cells because they have the same set of chromosomes in nucleus as other daughter cell
130
what is the formula to find out the number of cells there will be after multiple divisions of mitosis
number of cells= 2 to the power of n
| n= number of divisions by mitosis
131
what is growth
an increase in size or mass
132
what are 3 ways in which animal and plant cells can grow
cell differentiation
cell division
cell elongation
133
what is cell differentiation
process by which a cell changes to become specialised for its job
134
why is it good for multicellular organisms to have specialised cells
they can work more efficiently
135
how can animals and plants grow by cell division
mitosis
136
how can plants grow
cell elongation- where a plant cell expands, making the cell bigger- making plant grow
137
how does all growth in animals happen
cell division
138
where does cell division only happen in plants
tips of roots and shoots, areas called meristems
139
do plants stop growing
no, even old plants continue to develop new parts
140
what is the rate at which cells divide by mitosis controlled by
the chemical instructions (genes) in an organisms DNA
141
why might a cell start dividing uncontrollably
if there's a change in one of the genes that controls cell division, the cell might start dividing uncontrollably
142
what can uncontrollable division of a cell cause
mass of abnormal cells, called a tumor
143
when is a tumor called cancer
if it invades and destroys surrounding tissue
144
what are percentile charts used to do
monitor growth
145
what three measurements are taken for percentile charts
length, mass and head circumference
146
what are undifferentiated cells called
stem cells
147
what do stem cells found in early human embryos have the power to do
divide and produce any kind of cell at all
148
what are stem cells really important for
growth and development of organisms
149
where are stem cells found in adults
bone marrow
150
why are adult stem cells less versatile than embryonic stem cells
cant produce any cell type, only certain ones
151
how can stem cells turn into specialised cells
divide by mitosis to become new cells, and then differentiate
152
why are meristems only found in the roots and shoots of plants
because they are only found in areas where the plant is growing
153
what are the unspecialised cells produced by meristems able to do
able to divide and form any cell type in the plant- act like embryonic stem cells
154
how are the cells formed by unspecialised cells different from human stem cells
they can divide and differentiate to generate any type of cell for as long as the plant lives
155
what do unspecialised cells produced by meristems go on to become
specialised tissues like xylem or phloem
