N5 Flashcards
(139 cards)
1
Q
Function of the nucleus
A
Controls all cell activities and contains DNA
2
Q
Membrane function
A
Controls what substances can enter and leave the cell
3
Q
Cytoplasm function
A
Where chemical reactions happen
4
Q
Cell walls function
A
Gives cell shape and support
5
Q
Vacuoles function
A
Stores cell sap
6
Q
Mitochondria function
A
Site of aerobic respiration
7
Q
Plasmid function?
A
Circular ring containing DNA
8
Q
In what cells can a nucleus be found?
A
Animal
Plant
Fungi
9
Q
What cells can the membrane be found in
A
Animal
Plant
Fungi
Bacterial
10
Q
What cells can the cytoplasm be found in ?
A
Anima
Plat
Bacterial
Fungi
11
Q
In what cells can a cell wall (with cellulose) be found in
A
Plant
12
Q
In what cells can a cell wall (without cellulose) be found in
A
Bacteria
Fungal
13
Q
In what cells can vacuoles be found in
A
Plant
Fungi
14
Q
In what cells can mitochondria be found in
A
Animal
Plant
Fungi
15
Q
In what cells can ribosomes be found in
A
Animal
Plant
Bacteria
Fungi
16
Q
In what cells can plasmids be found in
A
Animal
Plant
Bacteria
17
Q
Formula for calculating size of cells
A
Length/breadth divided by number of cells
18
Q
What is the cell membrane composed of
A
Phospholipids and proteins
19
Q
What 2 words would be used to describe a cell membrane
A
Selectively permeable
20
Q
Define selectively permeable ?
A
It only allows the movement of some substances into the cell like small cells that can fit through
21
Q
What is diffusion?
A
The movement of molecules down a concentration gradient from a higher concentration to a lower concentration
22
Q
Why is diffusion important cells
A
It helps provide the cell with raw materials and helps to remove waste products
23
Q
What enters the cell during diffusion
A
Oxygen and amino acids
24
Q
What leaves the cell during diffusion
A
Carbon dioxide and urea
25
What is osmosis
The movement of water molecules from a higher water concentration to a lower water concentration. Through a selectively permeable membrane
26
What os active transport
The movement of molecules and ions from a lower concentration to a higher concentration against a concentration gradient
27
Active transport requires what and why
Requires energy to allow the proteins in the membrane to move the molecules against the concentration gradient
28
How would a DNA structure be described
A double stranded helix held by complementary base pairs
29
What are the 4 bases in DNA
Adenine
Thymine
Guanine
Cytosine
30
What do he bases in DNA form when put together
Complementary base pairs which means they only bond with certain pairs
A+t
G+C
31
What is a gene
A section of DNA which codes from a protein
32
What do long chains of amino acids make
Proteins
33
What do the sequence of bases determine
The amino acids sequence in proteins and the specific protein to be made
34
What is MRNA?
A molecule which carries complementry copy of the genetic code from the DNA in the nucleus to a ribosome where the protein is assembled from amino acids
35
Where are proteins made?
Ribosomes
36
What are the functions of proteins
Structural proteins - make p cell structures such as membranes
Enzymes - act as biological catalysts
Hormones - act as chemical messengers between cells
Antibodies - involved in body defences
Receptors - found in cell membranes and recognise specific substances
37
How is genetic information transferred from one cell to another
By genetic engineering
38
What is genetic engeneering used to do
To allow a species to make a protein that is normally made by another species
39
What does genetic engeneering allow
Pieces of chromosomes to be transferred from one species to another which then allows the recipient species to make new proteins
40
What are the 5 stages of genetic engineering
1- identify the section of DNA that contains the required gene for the source chromosome
2-extract the required gene / extract plasmid from the bacterial call
3-insert required gene into bacterial plasmid
4-insert plasmid into host bacterial cell
5- this produces a genetically modified organism (GM)
41
How must the chemical energy stored in glucose be released
By all cells through a series of enzyme controlled reactions called RESPIRATION
42
What does the energy used from the breakdown generate
ATP
43
What can the energy transferred by ATP be used fr
Cellular activities
44
What are the cellular activities produced with the energy from ATP?
Muscle cell contraction
Cell division
Protein synthesis
Transmission of nerve impulses
45
Where does aerobic respiration take place
In living cells when oxygen is present
46
Word equation from aerobic respiration
Glucose + oxygen —>carbon dioxide + water + energy
47
Aerobic respiration is a series…?
Of enzyme controlled reactions
48
What are the 2 stages of aerobic respiration
Breakdown of glucose
Breakdown of pyruvate
49
What are the details of stage 1 of aerobic respirations
Does not require oxygen
Occurs in the cytoplasm
Breaks down glucose into 2 molecules of pyruvate
Releases enough energy to make 2 ATP
50
What are the details of the second stage of aerobic respiration
Requires oxygen
Occurs in the mitochondria
Breaks down pyruvate into carbon dioxide and water
Releases enough energy to make many ATP
51
When does fermentation take place
In the absence of oxygen the fermentation pathway takes place
52
What is the word equation for fermentation in plant and fungal cells
Glucose —> carbon dioxide + ethanol + energy
53
Is the process of fermentation in the plant and fugal cells reversible?
No
54
Word equation for fermentation in animal cells
Glucose —> lactate + energy
55
Where does respiration begin
The cytoplasm
56
Is the process of fermentation in animal cells reversible
Yes
57
What do repirometers do
Measure teh rate of respiration
58
What are enzymes
Biological catalysts that speed up chemical reactions
59
What happens to an enzyme after a reaction
Nothing they stay un changed
60
What is the substance called of which an enzyme acts on
A substrate
61
What is the site called that binds the substrate to specific molecules
Active site
62
Enzymes are …? Because the shape of their active site is …? To the shape of its specific substrate
Specific
Complementary
63
What is a degradation reaction
Is where one large substrate is broken down into smaller products
64
What is a synthesis reaction
Where small substances are built up into a large product
65
When are enzymes most active
In their optimum conditions
66
What can enzymes and other proteins be affected by
Temperature and pH
67
What temperature do enzymes normally work best in
37 degrees
68
Denaturing an enzyme does what
Changes there shape which will affect the rate of reaction
69
Why do enzymes denature
If they are exposed to an incorrect ph or temperature meaning the shape of the active site has changed
70
What is the word equation for photosynthesis
Light energy
Carbon dioxide + water ——> sugar + oxygen
71
What are the 2 stages of photosynthesis
Light reactions
Carbon fixation
72
Stage 1 of photosynthesis ? In order
-light energy from the sun is trapped by chlorophyll in the chloroplasts
-light energy is converted into chemical energy which is used to generate ATP
-water is split to produce hydrogen and oxygen
-oxygen diffuses from the cell
-hydrogen and ATP are taken to the next stage
73
Stage 2 of photosynthesis?
- a series of enzyme controlled reactions
- uses hydrogen and ATP with carbon dioxide to produce sugar
74
How is the sugar from photosynthesis used ( 3 ways )
-Broken down during respiration to produce energy
-converted into starch which acts as an energy store
-converted into cellulose which cell walls are made from
75
What is a limited factor
One that limits how fast a reaction can go if it is short supply
76
What are the 3 limiting factors
Light intensity
Temprature
Carbon dioxide concentration
77
What does the nucleus of a cell contain
DNA which is organised into chromosomes
78
What is the chromosome compliment of a human?
46
79
How many sets of chromosomes do humans have
23
80
What is mitosis
The process of cell division
81
What are new cells needed for
Growth and repair of damaged cells and maintains diploid chromosome complement
82
What is the process of mitosis’s in order
-nucleus contains long uncoiled chromosomes which are difficult to see
-chromosomes make copies of themselves and become visible pairs of identical chromatids
-chromosomes line up along the equator , spindle fibres form at thee poles and attach to the centromeres
-spindle fibers pull chromatids apart from opposite poles of the cell
-daughter chromosomes gather at the poles of the cells
-cytoplasm divides forming 2 daughter cells which have the same diploid chromosome number as the parent cell
83
Why is it important for daughter cels to be identical to the parent cell
It ensures that no genetic information is lost
84
What are stem cells (in animals)
Unspecialised cells which can divide in order to self-renew
85
What do stem cells have the potential to do
Become differnt types of cells ( stem cells are involved in repair and growth
86
What are the 2 types of stem cells
Embryonic stem cells
Tissue. Stem cells
87
Where are embryonic stem cells found and what is there potential?
Found in the very early stages in embryos
Have the potential to become nearly all cells in the body
88
Where can tissue stem cells be found and what are there responsibilities
Found in tissues and organs of the body
Responsible for repair and growth
89
What are the 3 types of cell types
Tissue
Organ
System
90
Explain tissues
A group of cells with similar structure and function that all work together to do a particular job
91
Explain organs
A group of differnt tissues working together to preform a specific job
92
Explain systems
A group of differnt organs that work together to do a particular jog
93
What does the nervous system consist of
Brain
Spinal cord
94
Function of the cerebrum?
Memory
Thought
Intelligence
Reasoning
95
Cerebellums function ?
Balance and muscle co ordination
96
Function of medulla
Breathing rate and heart beat
97
What carries mesages along neurons
Electrical impulses
98
What are the 3 types of neurons (nerves)
Sensory
Inter
Motor
99
Explain the sensory neuron?
Pass the info to the CNS rom a receptor in the senses
100
Explain the inter neuron
Operate within the CNS which processes information from the senses that require a response
101
Explain the motor neuron
Enable a response to occur at an effector
102
What do receptors do
Detect a sensory input/stimuli from the receptor in he senses
103
Where are effectors found and what do they do
Found in the muscles and glands
They carry out a response
104
What is a reflex
A fast response to protect the body from harm
105
What is a synapse
A tiny gap between neurons
106
What does the endocrine gland do
Releases hormones into the bloodstream
107
What are hormones
Chemical messengers
108
What are hormones ade of
Protein and specifically affect target tissues
109
How is a target tissue alone targeted
It has cells with complementary receptor proteins for specific hormones so only that tissue will be affected by these hormones
110
How is a continuous supply of energy gained
Through respiration
111
What 2 hormones re involved in controlling blood glucose levels
Insulin
Glucagon
112
Where is insulin produced
By the pancreas and is carried in the blood to the target organ , liver
113
What does insulin do
Causes teh liver to take up glucose from the blood and convert it to a storage carbohydrate called glycogen and therefore reduces the levels of glucose in the blood
114
Where is glucagon produced
By the pancreas
115
What does glucagon do
Causes the liver to convert the storage carbohydrate glycogen to glucose and therefore increases the levels of glucose in the blood
116
Upper epidermis function
A transparent layer which allows sunlight to pass through to the cells blow
117
Palisade mesophyll function
Closely packed cells which contain many chloroplasts the main site of photosynthesis
118
Spongy mesophyll function
A lawyer of cells that contain may airspace’s where water gets evaporated
119
Stomata function
Pores on the underside of the leaf which allow gas and exchange and escape of water Vapor
120
Guard cell function?
2 cells which control the opening of the stomata
121
Vein function?
Contains xylem and phloem for water and sugar transport
122
What is a cell that has 2 matching sets of chromosomes called
Diploid
123
What are sex cells called
Gametes
124
How many sets of chromosomes do gametes have
1 (haploid)
125
How do plants like flowers reproduce
The pollen is produced in the anther and the ovule is produced in the ovary they meet and reproduce
126
What are the 2 gametes in humans called
Sperm
Egg
127
What is fertilisation
The fusion of the nuclei of the 2 haploid gametes to produce a diploid zygote which divides into an embryo
128
What is variation
Differences that can be seen between individual members of a species
129
Describe continuous variation
Range of values between a minimum and a maximum
Controlled by more than one gene (polygenic)
130
Describe discrete variation
Measurements fall into distinct groups
Controlled by a single gene
131
What is an alleles
A different form of gene
132
What is a genotype
The alleles that you have for different characteristics
133
What is a phenotype
The outward physical appearance and depends on your genes type
134
Describe homozygous
Individuals that have 2 of the same alleles for a gene
135
Describe heterozygous
Individuals that have 2 different alleles for a gene
136
population
number of organisms of one species in an area
137
producer
green plants that make its own food using light energy by photosynthesis
138
consumer
eats other organisms to obtain energy
139
herbivore
only eats plants material
