Unfamiliar concepts - Flashcards
(111 cards)
1
Q
Waters polarity -
A
Because the negative shared hydrogen electrons are pulled towards the oxygen atom, the other side of the hydrogen is left with a positive charge.
2
Q
Why ice is less dense -
A
Hydrogen bonding
fix positions of the molecule slightly further apart, producing a giant rigid open structure (oxygen is at the centre)
3
Q
Cohesion and adhesion -
A
Cohesion (coperative) attraction between the same molecule due to its polarity
Adhesion when water molecules are attracted to other materials.
4
Q
Golgi and ER = (Cristernae or Cristae)
Mitochondria =
A
G and ER = cristernae
Mito = cristae
5
Q
Protein Production -
A
1Ribosomes come from nucleolus leave through pores as are small,
2 Pass into cristernae and packaged into transport vesicles
3 contain newly synthesised proteins which move to the cytoskeleton
4 Vesicles fuse with the cis face on the golgi, structurally modified
5 secretory vesicles fuse with the membrane exocytosis lysosomes stay inside the cell
6
Q
Flagella difference between euk and prok -
A
P - made up of protein filaments when present arranged in helix.
E - made up of microtubules proteins in a 9+2 formation
7
Q
Glucose structure -
A
Glucose = c6 h12 o6
oh and h swapped between alpha and beta
Middle swapped, outside same of OH and H groups (observe in book)
Left top CH2OH
8
Q
Glycosidic bonds are what and created how?
A
Covalent bond
Condensation
Formed by the reaction of hydroxyl groups, existing bonds are broken.
9
Q
Monosaccharide - examples
A
Glucose, fructose and galactose
10
Q
Disaccharide examples -
A
Sucrose, lactose and maltose
11
Q
Polysaccharide examples -
A
Glycogen, starch, cellulose
12
Q
Ribose structure -
A
Pentose similar structure to beta glucose
13
Q
Starch -
A
Mixture of two alpha glucose polysaccs
Amylase (UB) = 1-4 gly bonds, angle of bonds forms an insoluble helix, stabilised by hydrogen bonds, good for storage
Amylopectin (B) = 1-4, 1-6 gly bonds, two glucose molecules, giving it a branched structure, enzymes can reach the branches quicker to break down the gly bonds releasing glucose, insoluble
14
Q
Glycogen -
A
Main energy source in animals, similar structure but has way more branches that the starch one, coiling and branching = storage, end branch is free meaning glucose can be removed and added, has more branches due to metabolism, alpha glucose
15
Q
Cellulose -
A
Plant cell walls - Hydroxl groups on 1 and 4 are too far to reach, turning to a beta glucose aswell can join the reaction together.
16
Q
Lipids polar or non-polar
A
Non-polar, due to the electrons being more evenly distributed than in polar molecules meaning there is no reasons of positivity or negativity
17
Q
Lipids are large MM?
A
Macromolecules, which are not built for repeating units.
18
Q
Triglyceride formation -
A
One glycerol and three fatty acids
19
Q
Glycerol belong to which group -
A
Alcohols
20
Q
Fatty acids belong to which group -
A
Carboxylic acids
21
Q
The process of triglycerides synthesising is and how many water molecules are formed -
A
Esterification and 3 water molecules
22
Q
Saturated fatty acids -
A
Do not have double bonds present between carbon molecules, general structure is CnH (2n+1) COOH
23
Q
Unsaturated fatty acids
A
Have double bonds between carbon atoms present , one being monosaturated, you get the picture with the others. This allows the molecule to bend and be packed closely together, liquid at room temperature
24
Q
Phospholipids -
A
These are modified triglycerides, inorganic ions are found in the cytoplasm of every cell and so negatively charged makes them soluble in water. Contain two fatty acid tails
25
Phosphate heads in the bilayer -
Polar and hydrophilic
26
Fatty acids in the bilayer -
Non-polar and hydrophobic
27
Cholesterol -
A sterol and important in the phospholipid bilayer, complex alcohol molecules, its positioned between the phospholipids, adds stability and keeps fluidity at low temperatures and stops them from becoming too fluid at higher temperatures.
28
General amino acid structure -
R Variable group
A group H2N - C - COOH Carboxyl group
H
29
What catalyses the peptide bonds forming -
Peptidal transferase present in the ribosome for the site of protein synthesis (translation)
30
Value of R groups in an amino acid -
Able to interact with each other, forming different types of bonds leads to long chains of polypeptides
31
Primary structure of a protein -
Peptide bonds and the sequence of amino acids, the particular amino acids will influence how the polypeptides fold to give the final shape.
32
Secondary structure of a protein -
Hydrogen bonds begin to form changing the initial folding of the polypeptide chain, start coiling, the oxygen, hydrogen and nitrogen atoms of the amino acid interact.
33
Tertiary structure of protein structures -
Overall 3D shape and ionic bonds, results in more bonds between the polypeptide chain, coiling or folding of secondary structures brings in the R group brings it closer together. Phillic and phobic reactions between polar and non-polar R groups, ionic bonds are stronger than H bonds and form between opposite charged R groups, disulfide bridges form between opposite R groups of proteins with some atoms that contain sulfur atoms.
34
Quaternary structure of proteins -
Involves the interactions of two or more subunits of alpha or beta, interactions same as tertiary, but between different protein molecules E.G Insulin has 2 subunits and haemoglobin has 4 subunits 2 the same.
35
Globular proteins -
Compact and water soluble, roughly spherical in shape, formed when they fold into their tertiary structures. Hydrophilic R groups are pushed outwards, hydrophobic R groups are pushed inside away from the aqueous environment.
36
Insulin as a globular protein -
Regulate blood glucose, in the pancreas, soluble in the bloodstream, needs precise shape to fit receptors, contains two polypeptide chains held by disulfide bridges.
37
Conjugated proteins -
Globular proteins which contain a non-protein part attached to them called a prosthetic group. Haem groups contain Iron ions Fe 2+
38
Haemoglobin as a conjugated protein -
Quaternary, made up of 4 polypeptides, two alpha and beta subunits, the Iron Ions are able to combine reversely with oxygen molecule, enables oxygen to be transported around the body.
39
Fibrous proteins -
Long chains of insoluble molecule, keratin, elastin and collagen tend to be strong, structural and unreactive proteins, not associated with long 3D complex shapes.
40
Interphase -
Long periods of growth.
-DNA is replicated and checked for errors
-Protein synthesis in the cytoplasm
-Chloroplasts and mitochondria grow and divide, increasing in number
41
Mitosis is when what divides -
Nucleus
42
Cytokinesis is when what divides -
Cytoplasm (two cells are produced)
43
Stages of interphase -
3
G1 - first growth phase, proteins from which organelles replicate, increases in size
S - DNA is replicated in the nucleus
G2 - second growth phase, continues to increase, energy stores are increased and the DNA is checked for errors .
44
G0 -
Cell leaves the cycle for a bit or forever
May be due to differentiation - where the cell becomes specialised to carry out a function and cannot divide
May be due to damaged DNA - where the DNA can no longer divide and enters a period of permeant cell arrest.
May be due to age - growing of many senescent (they eventually stop multiplying but don't die off when they should) cells have been linked with many age related diseases like arthritis.
45
Why are checkpoints in the cell cycle needed?-
Control mechanisms of the cell cycle modify and check the cell cycle to check they have been accurately been completed.
46
G1 checkpoint -
End of G1 phase, if satisfied it triggers DNA replication, if not G0
47
G2 checkpoint -
End of G2 phase, before the start of the mitotic phase, DNA has to be checked it has been replicated without an error if fine then it signals the beginning the molecular processes of mitosis.
48
Before mitosis DNA molecules of chromosomes have been converted into .......... . These are joined to region called
Chromatids
The two chromatids are joined together at a region called the centromere.
49
Before mitosis and before interphase DNA combines with proteins to form what -
Histones and chromatin
50
Prophase -
Chromatin begin to coil and condense becoming shorter and fatter to become chromosomes, nucleolus and nuclear envelope break down and the NE begin to but will eventually.
Protein microtubules form spindle-shaped structures linking the poles of the cell, the fibres forming the spindle are necessary to move the chromosomes into correct positions
Centrioles migrate to opposite poles of the cells where the chromosomes start to move to the centre of the cell from spindle fibres which attach to specific areas on the centromeres.
51
Metaphase -
Metaphase the chromosomes move to the centre of the cell from the influence of spindle fibres, region of the metaphase plate.
52
Anaphase -
The centromeres holding the pairs of chromatids in each chromosome divide. Chromatids divide pulling to opposite ends of the cell, by shortened spindle fibres.
53
Telophase -
Chromatids have reached the poles and are now called chromosomes, the nuclear envelope reforms around them, the chromosomes start to uncoil and the nucleolus forms, allowing cytokinesis
54
Animal cells cytokinesis -
Cleavage forms around the middle of the cell, the plasma membrane is pulled inwards by the cytoskeleton until it can fuse around the middle forming two cells.
55
Plant cells cytokinesis -
Cannot form cleavage due to cell walls of the plant cells, golgi releases vesicles around where the metaphase plate was formed, the vesicles fuse with each other.
56
Meiosis in sexual reproduction, what do the sex cells-
Two sex cells (gametes) = fuse together to form a zygote a fertilised egg. Gametes must contain half of the standard number of chromosomes in a cell. The nucleus divides twice forming 4 daughter cells so the gamete contains half the number of parent cells so is haploid and meiosis is known as reduction division.
57
Homologous chromosomes -
Each nucleus of the organisms cells contains two full sets of genes, pair of genes for each characteristic, therefore each nucleus contains matching sets of chromosomes.
58
Alleles -
Different versions of the same genes, so variations
59
Meiosis 1 -
Reduction division when the homologous pairs of chromosomes are separated into two new cells. Each intermediate cell will only contain one full set of genes.
60
Meiosis 2 what happends with cell production? -
Similar to mitosis, where the chromatids present in each daughter cell are separated, forming two more cells. 4 haploid cells are produced in total.
61
Prophase 1 -
Chromosomes condense, nuclear envelope disappears and so does the nucleolus and spindle formation begins as in mitosis. The homologous chromosomes pair up forming bivalents.
62
Metaphase 1 -
Same as in mitosis but homologous pairs of chromosomes assemble along the metaphase plate instead of individuals. The orientation of each homologous pair on the metaphase plate is random and independent of homologous pair. The maternal or paternal chromosomes end up of facing either pole. Independent assortment.
63
Anaphase 1 -
As the homologous chromosomes are pulled to the opposite poles and the chromatids stay joined together. Sections on the DNA sister chromatids which become entangled break off and re-join resulting in the exchange of DNA. These may be different alleles of the same gene these may be different form the allele combination on either the original chromatids, results in genetic variation.
64
Telophase 1 -
Essentially the same as mitosis where the chromosomes assemble at each pole and the nuclear membrane reforms and chromosomes uncoil. Divides into two cells from cytokinesis and the reduction of chromosomes number from diploid to haploid is complete.
65
Prophase 2 -
Chromosomes which consist of two chromatids, condense and become visible, the nuclear envelope, breaks down and the spindle formation begins.
66
Metaphase 2 -
Differs from metaphase as the individual chromosomes line up in the centre of the metaphase like in mitosis
The chromosomes are no longer identical so there is more independent assortment and genetic variation.
67
Anaphase 2 -
Chromatids in the individual being pulled to opposite poles after the division of the centromeres
68
Telophase 2 -
The chromatids assemble at the poles, uncoil and form chromatin again, nucleolus and nuclear envelope becomes visible again
69
Cytokinesis of Meiosis 2 -
- Division of cells forming
- 4 daughter cells in total
- Haploid due to reduction division
- Genetically different from crossing-over and independent assortment
70
Specialised cells are classed as what and what does this mean?
Specialised to carry out there own function
71
Specialised animal cells (Erythrocytes) -
- Biconcave shape
- Increases S.A/V ratio
- No nucleus or other organelles to maximise the space available for haemoglobin
- Flexible and can squeeze through capillaries.
72
Specialised animal cells (Neutrophils) -
- Immune system
- Multi-lobed nucleus to reach the site of infection through small gaps
- Cytoplasm contain many lysosomes which contain enzymes which are used to attack pathogens
73
Specialised animal cells (Sperms cells) -
- Male gametes
- Deliver genetic information to the female gamete
- Flagellum and many mitochondria to supply the energy needed to swim
- The acrosome (head) contain digestive enzymes which release and digest the protective layers around the ovum allowing the sperm to penetrate and lead to fertilisation
74
Specialised plant cells (Palisade cells) -
- Found in the mesophyll
- Absorb large amounts of light for photosynthesis
- Closely packed due to their box shape
- Thin cell walls
75
Specialised plant cells (Root hair cells) -
- Long extensions of root hairs increasing surface area
- Maximises the uptake of water and minerals from soil
76
Specialised plant cells (Guard cells) is necessary for and do what?-
- Form small openings o guard cells
- Necessary for CO2 to enter
- When guard cells become less swollen due to water loss the stomata close to prevent further water loss
- Cell wall is thicker on one side so the cell does not change symmetrically as its volume changes.
77
What is a tissue and examples? (Specialised cells)
Collection of differential cells that have specialised functions, so each tissue is adapted for a particular function, 4 main: Nervous, electrical impulses, epithelial, cover body surfaces, muscle, adapted to contract, connective hold tissues together or act as a transport medium.
78
Specialised animal tissues (Squamous epithelium) -
- Very thin due to the flat cells
- Once cell thick
- It is present for rapid diffusion to take place
- Lining of the lungs to allow rapid diffusion of oxygen into the blood
79
Specialised animal tissues (ciliated epithelium) -
- Hair like structures called cilia
- Lines the trachea
- Causes mucous to be swept away from the lungs
- Goblet cells - traps any unwanted particles present in the air from secreting mucous
- Stops them from reaching the alveoli inside
80
Specialised animal tissues (cartilage)-
- Connective tissue
- Contains the fibres proteins elastic and collagen
- Firm and flexible
- Consists of chondrocyte cells embedded in the extracellular matrix
- Prevents the ends of bones rubbing together to stop causing damage, many fish have this.
81
Specialised animal tissues (muscle) -
- Must contract in order to move over bones
- Move different parts of the body
- Different types of muscle fibres.
82
Specialised plant tissues (epidermis) -
- Single layer of closely packed cells covering the surfaces of the plant
- Usually covered with a waxy, waterproof cuticle to reduce the water loss.
- The stomata is present in the epidermis allowing O2, CO2 and water in and out.
83
Specialised xylem tissue -
- Vascular tissue responsible for the movement of water and minerals
- Composed of vessel elements which are elongated dead cells
- Lignin - provide structural support for the plants which are waterproof
84
Specialised phloem tissue -
- Vascular tissue
- Transport of organic molecules of food (sucrose)
- Composed of sieve tubes separated by sieve plates
85
What is a vascular tissue?
Adapted for the transport of water and nutrients
86
Stem cells are different to specialised cells as they are classed as?
Undifferentiated
87
Stem cells are undifferentiated as?
They are specialised for any function, and have the potential to differentiate into one of a range of specialised cells.
88
What does potency mean?
A stem cells ability to differentiate into different types of cells. The greater the number of potency the greater the number of cells they can differentiate into.
89
Totipotent (stem cells) -
These are stem cells that can differentiate into any type of cell (fertilised egg or zygote). It's first few divisions are totipotent cells which are destined to produce a whole organism.
90
Pluripotent (stem cells) -
These stem cells can form all tissue types but not whole organisms, present in early embryos.
91
Multipotent (stem cells) -
These stem cells can only form a range of cells within a certain type of tissue, for example Haematopoietic stem cells in the bone marrow these give various types of blood cells inside of a certain tissue.
92
All blood cells are derived from stem cells in the?
Bone marrow
93
Differentiation in animals and plants - (read)
Multicellular organisms have evolved from unicellular organisms because groups of cells with different functions work together, this can be broad.
94
Replacement of red and white blood cells. Why is it needed?
Lack of organelles and nucleus they have a short life span, so need to be replaced constantly, the stem colonies in the bone marrow produce three billion erythrocytes per kilogram of body mass. Neutrophils are essential in the immune system and also produce large colonies of stem cells in the bone marrow.
95
Sources of animal stem cells -
Embryonic stem cells are present at very early stages of embryo development, totipotent
Tissue stem cells are present since birth, multipotent but evidence suggest they can be artificially triggered to become pluripotent.
96
Sources of plant stem cells -
Stem cells are present in the meristems in plants, located between phloem and xylem, cells from this region differentiate into different cells in both plant tissues, in this way the vascular tissue grows as the plants grow. Pluripotent stem cells in meristems.
97
Uses of stem cells -
Heart disease, type 1 diabetes - lack of insulin and is dependant in the body, Parkinson's - dopamine producing cells in the brain. Alzheimer's disease - brain cells destroyed due to the build up of abnormal proteins, drugs only alleviate the symptoms.
98
Stem cell ethics -
- Plant cells do not spark as much debate as animals cells
- Removal of stem cells from embryos can result in the destruction of embryos
- People believe that life begins at conception therefore and the destruction of embryos is murder.
-
99
Anabolic reactions - (A)
Chemical reactions required for growth (add), catalysed by enzymes.
100
Catabolic reactions -
Chemical reactions which result in many breakdown reactions. Energy is released in these reactions because of the broken bonds.
101
V - Max?
Enzymes can only increase reactions up to a give point.
102
Enzyme/substrate complex -
When active site is filled with the correct complementary pairing.
103
Enzyme/product complex -
Products/product formed due to the enzyme-substrate complex success and reaction.
104
Induced fit hypothesis -
As the active site changes shape due to the interaction of the bond between substrate and enzyme. Causes changes in the tertiary structure.
105
Intracellular and extracellular examples -
I = Catalase -turns hydrogen peroxide into water and oxygen. (Toxic gas)
E = Amylase - made in salivary glands and pancreas and moves to the saliva (produced in cells to be secreted out).
106
Temperature efficient Q10 -
A measure of reaction of how much rate of reaction increases with every 10 degrees Celsius increase.
106
Single celled organisms and there use of enzyme secretion -
Secreted into the environment and used to break down larger molecules into smaller ones to be absorbed by the cell.
107
Denaturisation of enzymes (what happens when enzymes have denatured above optimum temperature) -
The ROR is rapid and a slight change of the active site will stop many enzyme-substrate complexes. Q10 does not apply anymore. The ROR is less extreme closer to the optimum as enzymes have not fully denatured.
108
pH as a factor influencing enzyme activity -
As well a temperature and enzyme concentrations. A change in pH effects enzyme activity
A change in hydrogen ion concentration (H+) results in a change of pH concentration. Low pH = acidic and high pH means alkaline. The active site will only be right if the number of H+ are correct.
- More hydrogen ions = less pH
- Less hydrogen ions = More pH
109
Renaturation of enzyme -
If pH returns to its normal in the protein, it can catalyse reactions again.
110
