Bio BME Flashcards
(128 cards)
1
Q
What are the two names bases are divided into and what bases go with these names
A
Bases are divided into purine and pyrimidine.
Purine: A and G
Pyrimidine: T C U
2
Q
What is a nucleoside
A
Base and sugar with no phosphate group
3
Q
How does polarity arise in DNA
A
Due to phosphodiester bond which offers directionality/polarity of the molecule.
4
Q
What are chromatids made of
A
Made of solenoids which are composed of nucleosomes
5
Q
What is a nucleosome
A
Part of the structure of chromosomes where DNA is wrapped around his tone proteins
6
Q
Define transcription
And the steps
A
First step of gene expression we where DNA is copied into RNA
Consists of initiation, elongation and termination
7
Q
what is the primary structure of the protein
A
AA are linked by peptide bonds and resultant polypeptide chain has an N terminus and C terminus which coincides with their amino and carboxyl ends
8
Q
what is the secondary structure of a protein
A
carboxy and amino group are highly polar thus gives C-N bond a slight double bond character allowing H-bond=>linear polypeptide chain able to fold to certain structures ie alpha helix or beta pleated sheet
9
Q
what is collagen
A
fibrous protein with triple helix (intertwined of 3 polypeptide chains)
10
Q
what does haemoglobin have in terms of structure
A
2 alpha globin & 2 beta globin chain
11
Q
explain quaternary structure
A
protein structure made of 2 more polypeptides chains forming oligomers *(few subunits)-> subunits can be same(homomers) or diff (heteromers)
12
Q
what do lipoproteins do
A
carries dietary fats in blood
13
Q
what is the function of albumin
A
one major protein carrier molecule in blood that bind to drugs, allergens etc
14
Q
what is one of the function for collagen and fibrin
A
critical role in wound healing and hemostasis
15
Q
Define mutation
A
Alteration in DNA sequence which can result form chemicals, irradiation, lack of repair of replication mistakes
16
Q
What are viruses that infect bacteria called
A
Bacteriophages
17
Q
What main process does viruses lack
A
Homeostasis-> capacity tor emulate and sustain internal environment
18
Q
What is nucleocapsid in virus
A
Is the genome and the capsid together
19
Q
What are oncoviruses
A
Viruses linked with the development of cancer-> produce proteins that inhibit or deteriorate the function of TSG which play key role in cell division
Inactive TSG= cell grow uncontrollably therefore tumour forms
20
Q
How is HIV caused
A
Retrovirus that causes severe dampening of immunity by depleting T-lymphocytes=> opening sufferer to opportunistic infections
21
Q
What is cancer (human papilloma virus)
A
Cervical cancer is induced by oncogenic proteins produced by special types of human papilloma virus
22
Q
What is virion
A
The complete infective form of a virus outside a host cell with core of RNA and capsid
23
Q
Define virulence
A
Degree of pathology caused by pathogen
24
Q
What are the ways prokaryotes reproduce (4)
A
Binary fission
Transduction
Transformation
Conjugation
25
What is a capsule on a prokaryotic cell
Polysaccharide that aid prokaryotes such as bacteria to adhere to surfaces and to each other also prevent desiccation of microbe
26
What is appendages on prokaryotic cells
prokaryotic cells contain a few appendages which are protrusions on the cell surface such as fimbriae, pili and flagella.
27
What are fimbriae, pili and flagellum
- Fimbriae are thin filaments that aid adhesion.
- Pili are longer structures that play a role in conjugation and in some cases movement, whilst
- flagellum is a structure that helps the cell to move around.
28
what are peroxisome in the eukaryote cell
aids in metabolizing waste
29
define binary fission
process of asexual reproduction that bacteria uses to divide creating 2 identical daughter cells
30
define conjugation
direct contact used to transfer genetic material between bacteria
31
define transformation
exogenous DNA transferred into host
32
define transduction
process virus transfer genetic material between bacteria-> performed by bacteriophages
33
what is secondary active transport
example of coupled transport which utilized electrochemical potential difference established by the movement of ions for transport ie H pumps create electrochemical gradient which can be used via electron transport chain for cellular respiration in mitochondria
34
what is pinocytosis and what is it
cellular drinking
plasma membrane creates channel allowing dissolved substances to enter cell
35
what is phagocytosis
cellular eating
36
what is a pinosome
fluid filled vesicle within a cell
37
what is the enzyme oxidoreductases
and the 6 groups
what are the 6 groups
enzymes involved in oxidation and reduction
categorised into 6 main groups: oxidases(O as hydrogen or e- acceptor), dehydrogenase(oxidize substrates by transferring 1 or more hydride ions), oxygenase(incorporate O into organic substrate), hydroxylases(add hydroxyl group to substrate), hydro peroxidases(reduce of hydrogen peroxide and hydroperoxide) and reductases(catalyze reduction)
38
where does glycolysis occur
anaerobic reaction that occur in cytosol
39
what are the two types of metabolism and describe them
catabolism: breakdown of molecules ie glucose to pyruvate in glycolysis
anabolism: synthesis of compounds and molecules ie protein synthesis
40
define cytosol
intercellular fluid-liquid compartment of the cell
41
define muscular cramps
involuntary muscle contraction which causes significant pain and paralysis like immobility of the affected muscle usually due to lactic acid build up in muscle
42
what is the tumour suppressor protein in G2 phase in the cell cycle
p53
one of mainstays of cancer is mutation of p53= cause uncontrollable cell division
43
describe prometaphase
chromosomes led by their centromere align in centre of cell at right angle to centrosomes
spindle fibres bind to kinetochore, chromosome's continue to condense
44
describe metaphase
chromosomes attach to metaphase plate of mitotic spindle
45
describe anaphase
centromere divide and sister chromatid are separated to opposite ends of cell by mitotic spindle pulling on kinetochore
46
what is metaphase plate
plane in equatorial region of spindle in dividing cells, along which chromosome's become arranged during metaphase
47
what is a kinetochore
protein structure that forms on chromatid during cell division and allows to attach to spindle fibre on chromosome
48
what are the 4 steps in DNA replication in prokaryotes
initiation
unwinding
elongation
termination
49
describe initiation of DNA replication in prokaryotes
Initiation: The origin for DNA replication in E. coli is known as oriC, this genetic
locus contains the binding site for the initiator protein DnaA, single stranded binding
protein (5sb) holds the DNA bubble open allowing DnaB protein to bind! DnaB is a
helicase which uses ATP to melt double stranded DNA
50
describe unwinding of DNA replication in prokaryotes
Unwinding: After DNA helicase travels along the template strand and opens it for
copying, supercoiling is prevented by DNA gyrase (type Il topoisomerase). DNA Eyrase lessens supercoiling (relaxes tension) which builds up during DNA unwinding
preventing DNA breakage,
51
describe elongation in DNA replication in prokaryotes
Elongation: leading and lagging strand primers are elongated by the DNA polymerase
Ill holoenzyme, the subunit is a dimer, the leading and lagging strands are synthesized
simultaneously. The leading strand is made as a continuous piece (5-3 direction)
whilst the lagging strand is made in fragments (okazaki) in a 3-5 direction (see fig 1),
The looping of the lagging strands makes the process possible, DNA polymerase I fills
in the gaps once the primers are removed, DNA ligase makes the final phosphodiester
bond between the fragments.
52
describe termination in DNA replication in prokaryotes
Termination: the 2 replication forks meet 180 degrees opposite orC, these forks
are arrested by binding the tus gene product at termination sites around this region.
Topoisomerase IV unlinks the interlinked product which can now be separated into
the 2 daughter cells.
53
define OriC
the site of initiation of bacterial chromosomal replication
54
what is DNA gyrase
type of topoisomerase ll which reduces supercoiling of DNA, under winds DNA molecule (negative supercoiling)
55
what is DNA polymerase lll
what is DNA polymerase l
enzyme utilized in prokaryotic DNA replication for the leading and lagging strand
enzyme utilized tor remove RNA primer and replace it with nucleotides which allows connection of okazaki fragments. Also have DNA repair function
56
what is folic acid deficiency
folic acid is made from folate (vitamin B9) deficiency leads to anaemia
Folic acid utilised in synthesis of DNA
57
what are the 3 steps of transcription
Initiation: RNA polymerase binds to double stranded DNA and initiates transcription
at regions called promoters, where DNA unwinds (hydrogen bonds are broken), the
enzyme aids RNA synthesis (see fig 1). RNA polymerase and its cofactor are known as
the transcription complex. No primers are required.
Elongation: RNA polymerase locally unwinds the DNA strand as it adds on
ribonucleotides to the growing 3'end of the RNA strand. Thymine is exchanged for
uracil in a RNA molecule.
Termination: begins with the dissociation of the transcription complex which occurs
at the terminator site (specific DNA sequence). These terminator sites usually have
hairpin or stem loop structures which ceases transcription. This process may be rho-
dependent or rho-independent. Initiation: RNA polymerase binds to double stranded DNA and initiates transcription
at regions called promoters, where DNA unwinds (hydrogen bonds are broken), the
enzyme aids RNA synthesis (see fig 1). RNA polymerase and its cofactor are known as
the transcription complex. No primers are required.
Elongation: RNA polymerase locally unwinds the DNA strand as it adds on
ribonucleotides to the growing 3'end of the RNA strand. Thymine is exchanged for
uracil in a RNA molecule.
Termination: begins with the dissociation of the transcription complex which occurs
at the terminator site (specific DNA sequence). These terminator sites usually have
hairpin or stem loop structures which ceases transcription. This process may be rho-
dependent or rho-independent. The RNA transcript undergoes modification such as
3' polyadenylation, 5' capping, RNA splicing to prevent molecular degradation, then it
enters the cytoplasm via the nuclear pores. The RNA transcript undergoes modification such as
3' polyadenylation, 5' capping,, RNA splicing to prevent molecular degradation, then it
enters the cytoplasm via the nuclear pores.
58
what are the 3 types of modification pre mRNA go through
The RNA transcript undergoes modification such as
3' polyadenylation, 5' capping, RNA splicing
59
apart from mRNA what are the other other products of transcription
microRNA
transfer RNA
small nuclear RNA
riboenzyme
60
what are retroviruses
RNA virus which utilise RNA dependant DNA polymerase to replicate the RNA genome through a DNA intermediate (reverse transcription)
61
what is a transcription complex
consists of RNA polymerase and transcription factors this complex usually initiates transcription
62
what is hairpin in transcription
site that can terminate transcription= allows release of transcript
63
what is polyadenylation
poly-A tail that stabilizes mRNA and prevents degradation= also allows export of mRNA from nucleus
64
what is capping
stabilizes mRNA protects it from degradation from phosphatases, nucleases and halps initiate transcription
65
Describe the intimation step in proteins synthesis
Initiation: The main aim of this step is to assemble a ribosome molecule onto the
start/initiation codon (AUG) of an mRNA molecule. The components of this first stage
are the large and small ribosomal units, mRNA, tRNA, initiation factors and GTP. The
initiation factors bind to ribosome, together they recognize ribosome binding site
(BS) on the mRNA molecule, initiator tRNA binds to the P site by base pairing with
its anticodon to the codon on the mRNA. There are 2 sites for tRNA binding sites on
the ribosome (Aminoacyl and peptidyl sites) (see fig 1). AUG encodes methionine.
66
Describe the elongation step in protein synthesis
Elongation: This stage begins when the 50S subunit of the ribosome binds forming
the 70S complex; there are 3 main steps in this stage, amino-acyl-tRNA delivery,
peptide bond formation and translocation. Subsequently after amino-acyl-tRNA
delivery, A and P sites are filled and peptidyl transferase activity of the 50S subunit
forms the peptide bond between the 2 amino acids. Discharged tRNA moves on
to the exit site and is ejected when the next aminoacyl-tRNA (see fig 1). Eukaryotic
mRNA translation usually involves a 80S ribosome and occurs in the cytosol
67
Describe the termination set in protein synthesis
Termination: Cycle is repeated until one of the three termination codons (UAA,
UAG, and UGA) is encountered. Release factors aid the release of the polypeptide
chain. If a base is damaged or no encountered stop codon, a ribosome may stall on
an mRNA. The newly made polypeptide chain usually undergoes further processing
in the Golgi apparatus after which it may be stored or released.
68
What regions of the mRNA translate into a protein
And what are the untranslated regions called
Region between initiation and the termination condon
Upstream and downstream
69
What is the aminoacyl site
Binding site for charged tRNA molecules during protein synthesis. First site tRNA binds to on ribosome
70
What is the peptidyl site on the ribosome
SND binding site for tRNA on ribosome at which tRNA holding growing polypeptide chain bind unto
71
what is the law of dominance suggested by mandel
What is the law of segregation
What is the law of independant assortment
Law of Dominance: between 2 different alleles, the dominant one usually masks the other.
Law of Segregation: chromosomes segregate into gametes in order to pass on genetic information.
Law of independent assortment: alleles on different chromosomes are randomly distributed into individual gametes.
72
Define sexual reproduction
Complex process where 2 haploid gametes fuse to form a diploid cell
A new individual is formed by combination of sex cells from parents thus producing a new combination of genes
73
What are allosomes
Sex chromosomes
74
What is lyonization
X-inactivation which leads to formation of Barr body
One X chromosome in every cell in female is randomly inactive in early development
75
What is skewed inactivation
Preference to which X chromosome is inactivated in all cells
76
Define Barr body
Inactivated X chromosome
77
What is muscular dystrophy
Muscles degenerate and affected body’s are weak and immobile bc mutated dystrophin protein which provides structural support to muscle allowing withstand physical stress of contraction
78
How does Color blindness occur
Mutation in gene that encode ops in= visual pigment in cone cells of retina
79
What is hemophilia
Hemophilia: 2 forms of hemophilia are X-linked; hemophilia is bleeding disorders, hemophilia A is due
to mutation of factor 8 whilst hemophilia B is due to mutation of factor 9. These factors play a vital role in the clotting and hemostasis.
80
What is azoospermia
Azoospermia: cause of male infertility, there are no sperm cells in the semen produced.
81
What is fragile X syndrome
Fragile X syndrome: learning disabilities, cognitive impairment and mental retardation due to mutation in the fragile X mental retardation 1 (FMR1) gene
82
What is Alpert’s syndrome
Alport's syndrome: a triad of eye problems, kidney and ear issues, and sufferers can have blood in the
urine. Mutation in a gene that encodes collagen.
83
How does the body correct errors in DNA and explain it
Via base excision repair mechanisms= process utilised to repair damaged DNA removes helix distorting base pairs in DNA molecule
84
How can aneuploidy occur
Loss or gains of chromosomes and may also involve autosomes and allosomes
Arises form non disjunction (failure to separate) during meiosis leading to monosomy, trisomy and tetrasomy (examples of conditions being Down syndrome(trisomy of chromosome 21) etc )
85
What is translocation of chromosome
And what is fusion protein
Portion of chromosome has been transferred to another chromosome that can be reciprocal(balance exchange between homologous chromosome thus no genetic material lost) or robertsonian (entire chromosome attaches to another via centromere) => can lead to fused genes which produce fusion proteins
Products of fusion gene= 2 genes joined together
86
What is ring chromosome
Chromosome ends fuse together forming ring=> may arise due to radiation
87
What’s is polymorphism
Variegation in genteric material which is common in population >1%
88
What is monosomy
What is trisomy
What is tetrasomy
Loss of a set of chromosomes-> individual has only 1 set
3 sets of chromosome instead of 2
Having double the normal set so 4 instead of 2
89
What is UV radiation
Invisible ray of energy form sun (3 types UVA, B and C)
90
What is prader willi
Condition linked with imprinting-> usually inherit silenced maternal copy of prader willi gene and functional paterna gene . Condition arises form mutated paternal copy
91
How does angelman syndrome occurs
Maternal copy of gene is nonfunctional due to mutation whilst paternal copy is imprinted earlier in embryonic development
92
What is the overview process of human cycle starting
1. Starts with meiosis to form gametes
2. Fertilisation
3. Mitosis to from new individual
93
How long does it take for spermatogenis to occur and where does it occur and what happens here
70 days
Seminiferous tubules= diploid germ cell undergoes mitosis forming type A and B cells which later differentiates into primary spermatocytes
94
Way happens to the primary spermatocytes
Undergoes first round of meiosis to form 2 haploid secondary spermatocytes
These then divide mitotically into 4 haploid spermatids by meiosis ll
95
What are Sertoli cells
Nurse cells that aid spermatogenesis by providing nourishment and their junctions form blood testis barrier
96
Why do testicles hang lower in male bodies
Spermatogenesis requires cooler temp and core body temp
97
Label this diagram
98
What are the last steps of spermatogenesis (4)
1. After formation of spermatids cells undergo spermiation where they are released into the lumen of the seminiferous tubules prior to their transport to epididymis
2. In epididymis sperm is stored and undergoes final stage of maturation
3. Semen produced during ma,e ejaculation contains sperm and secretion form prostate, seminal vesicles and bulbourethral glands aiding sperm cell to overcome unique environment of female reproductive tract
4. Once semen introduced into female reproductive tract capacitation occurs allowing sperm to fertilise egg cell
99
What is oogenesis
Process where meiosis leads to formation of egg cell (gamete)
100
Describe stages of when an ovum forms
1. primary oocytes are
arrested in prophase I until the female reaches puberty.
2. During each month,
one oocyte resumes meiosis (ovulation) where a secondary oocyte which receives the
majority of the cytoplasm and a polar body forms.
3. The haploid secondary
oocyte initiates meiosis I however this halted at metaphase Il until fertilization, therefore if the egg is not fertilized the cell never becomes an ovum and its shed via
menstruation.
4. If fertilization occurs then meiosis I commences forming an ootid and
another polar body, ootid eventually matures into an ovum.
5. Polar bodies
form to discard extra sets of chromosomes ensuring the final egg cell is haploid.
101
Describe stages of fertilisation (6)
1. This is the union between the egg and sperm cell nucleus. This process produces a zygote which is the initial cell of the foetus/baby which eventually divides via mitosis
to form an embryo.
2. Capacitation occurs as the sperm swims through the uterus into the oviduct, only a capacitated sperm cell can partake in fertilization. 3. Capacitation is the process
whereby the membrane over the sperm's acrosome is weakened due to chemical changes; enzymes are released from the capacitated sperm which then clears a path
through the zona pellucida of the egg cell.
4. Only one sperm cell fuses with the oocyte, once this occurs, rapid chemical changes take place across the cell membrane of the oocyte preventing more sperm entry.
5. Fusion with sperm allows maturation of oocyte into an ovum and a polar body.
6. The formed zygote has 46 chromosomes, 23 from each parent.
102
Way this the epididymis
Structure choose to testicle where sperm cells are stored and undergo maturation
103
What is the menarche
First menstrual period
104
Wha this oogonium
An immature female reproductive cell that gives rides to primary oocytes by mitosis
105
What is a primary oocyte
Gives rise to secondary oocyte and polar body after meiosis l
106
What is Ootid
Wha this ovum
What is polar body
Ootd : an egg cell that results from the second meiotic division of an oocyte and that develops into a
mature egg
Ovum: after fertilisation the ootid goes through its final stage of maturation and becomes an ovum, a
fully mature human egg cell.
Polar body: a structure utilised to dump genetic material, formed during oogenesis
107
What is prostate gland
What is seminal vesicle
What is the bulbourethral gland
Prostate gland: gland just under the bladder that contribute substances to semen
Seminal vesicles: a structure that produces the bulk of semen
Bulbourethral glands: glands that also contribute substances found in semen. Also known as cowper's
gland
108
Define immunity
Body’s capacity to resist and combat infections
109
Label names that act these process’s
110
Explain process of each
111
112
How does adaptive immunity recognise self vs non self
Major histocompatibility complex (MHC) is a protein marker on the body cell surface which are recognised by T cells
113
What are the 5 classes of antibodies and each of their functions
IgM: are the first antibodies secreted during immune responses
IgG: are efficient in activating complement proteins, neutralizing toxins, they also indicate previous
infection.
IgA: are the most abundant antibodies in secretions (tears, saliva, and breast).
IgD: are part of the B cell receptor and aid the activation of B cell
IgE are anchored to the surface of mast cells, eosinophils and basophils which induce degranulation of these cells when bound to antigen.
114
115
Wha this complement cascade
Part of immune system that enhances (complements) ability of antibodies and phagocytes cells too clear microbes and damage cells from an organism, promote information, and attack the pathogen cell membrane
116
What are cytokines
Category of signalling molecule that mediate and regulate immunity, information on hematopoiesis (blood cell manufacturing)
117
What are T-Regulatory cells
 have a role in regulating or suppressing of the cells in the mean system
118
What is an anaphylactic shock
An allergic reaction, including the most extreme form that occurs because the body immune system reacts inappropriately in response to a substance that is wrongly perceived as a threat
119
 What is inflammation and common causes
Physiological response to tissue injury which can be due to embedded foreign inanimate object, chemical agents, physical trauma, a pathogen
120
How is inflammation categorised
Increased blood flow leading to fundamental signals which includes temperature pain redness swelling and possible loss of function of affected area
121
What is Involved in the process of inflammation
Many cells i.e. neutrophils, macrophages, mast cells etc and mediators i.e. histamine, serotonin, cytokines, prostaglandins, Leukotrienes
122
Describe acute inflammation (2)
And what is the outcome of acute inflammation
1. Involves vasodilation which is a process that increases blood flow to area, walls of blood vessels become Permeable to clotting factors, white blood cells whose aim is to reduce spread of microbe.
2. Histamine and nitric acid is primary mediators that induce vasodilation and increased vascular permeability after the neutrophils are recruited via chemotaxis, monocytes which eventually turn into macrophages engulf debris
Outcome: resolution, fibrosis, abscess formation or chronic inflammation
123
What is the main aim of inflammation
To clear initial cause of injury, remove necrotic cells and damaged tissue and initiate tissue repair
124
125
what are 3 process that promote evaluation
Natural selection, adaption and genetic drift
126
What is speciation
When a population cant interbreed successfully due to acquisition of many genetic differences thus making the 2 diff species
127
Waht is extinction and what are causes
Inability for an organism to evolve and so can lead to disappearance of an entire species
Competition between species, inability to adapt to their ever evolving environment, human activity (ie hunting, global warming)
128
Define primates
Define manual dexterity
What are homo Neanderthals
What are homo erectus
- Primates: any member of the biological order Primates, the group that contains all the species
commonly related to the lemurs, monkeys, and apes, with the latter category including humans
- Manual dexterity: ability to use hands in a skillful manner, precise and grasping movements.
- Homo neanderthals: Species of primitive human beings that lived between 28,000 and 300,000 years
ago
- Homo erects: extinct species that gave rise to humans whose teeth were larger and brain was smaller.
