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bio questions > voice of the genome > Flashcards

voice of the genome Flashcards

1
Q

how is DNA organised in a bacterial cell?

A
  • large circular DNA
    *DNA not associated with histone proteins
  • several small plasmids
  • located in the cytoplasm
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2
Q

what are the roles of the Golgi apparatus and vesicles in the formation and transport of extracellular enzymes?

A
  • vesicles fuse w Golgi apparatus
  • modification of proteins inside Golgi apparatus
  • protein packaged into secretory vesicles
  • vesicles fuse w cell surface membrane
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3
Q

what happens to lysosomes once their contents have been digested?

A
  • lysosome fuses w cell surface membrane
  • contents of lysosome released from cell/ exocytosis
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4
Q

how can eukaryotic organisms be differentiated from prokaryotic?

A
  • membrane bound organelles
  • mitochondria, RER, SER, nucleus, Golgi, vesicles
  • larger ribosomes
  • linear DNA associated w histone proteins
  • no plasmids in cytoplasm
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5
Q

how can prokaryotic cells be identifies?

A
  • circular DNA/ plasmids
  • 70s ribosomes
  • pili/ flagellum
  • capsule/ mesosome
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6
Q

why can the nucleus not be observed at the end of prophase?

A
  • nuclear membrane is broken down
  • DNA is coiled and condensed into individual chromosomes
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7
Q

what are the functions of the Golgi apparatus?

A
  • modifies proteins
  • forms vesicles
  • removes some water from the protein
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8
Q

where does protein synthesis occur in eukaryotic cells?

A

80s ribosomes on the endoplasmic reticulum

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9
Q

where is the capsule located in some bacteria?

A

outside the cell wall

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10
Q

what is the function of plasmodesma?

A
  • cytoplasmic connection between cells
  • which allows transport/ communication between cells
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11
Q

why is HCl added to the root tip when observing cell division?

A
  • breaks down middle lamella
  • allowing cells to be separated
  • to allow light to pass through
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12
Q

why is a stain added to the root tip when observing mitosis?

A
  • makes the chromosomes visible
  • so that the stages of mitosis can be identified
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13
Q

how does the shortening of spindle fibres affect mitosis?

A
  • sister chromatids cannot be separated
  • anaphase cannot occur
  • daughter cells produced with incorrect numbers of chromosomes
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14
Q

what are the events of fertilisation that occur after the acrosome reaction?

A
  • fusion of sperm cell w egg cell membrane
  • cortical granules release contents into zone pellucida
  • contents of cortical granules react w zoned pellucida
  • zona pellucida hardens
  • fusion of sperm and egg nuclei
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15
Q

why may offspring be genetically different?

A
  • each zygote is formed from different gametes
  • each gamete contains different combinations of alleles
  • due to independent assortment/ crossing over
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16
Q

what is meant by the term sex- linked disorder?

A
  • caused by a mutated gene
  • located on the X/Y chromosome
  • more likely in one gender
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17
Q

how are vesicles involved in the successful fertilisation of an egg?

A
  • cortical granules fuse w egg cell membrane
  • releasing enzyme that hardens zone pellucida
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18
Q

how can meiosis lead to genetic variation?

A
  • independant assortment of chromosomes
  • crossing over between chromatids
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19
Q

why do some genes show linkage and others show sex linkage?

A
  • there are more genes than there are chromosomes
  • linkage relates to genes located on the same chromosome
  • sex linkage relates to genes on the same X/Y chromosome
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20
Q

what is the meaning of polygenic?

A
  • a characteristic showing continuous variation
  • caused by multiple genes at different loci
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21
Q

how can epigenetic changes affect the development of tissues in the embryo?

A
  • DNA is wrapped around histones
  • acetylation of the histone affects binding of RNA polymerase
  • methylation of DNA affects transcription of genes
  • so gene expression is altered
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22
Q

what is the difference between a tissue and an organ?

A

a tissue is made if one type of cell and an organ is made of different tissues

23
Q

what are the decisions that society has to make about the use of embryonic stem cells?

A
  • totipotent so can be used in a wider range of therapies
  • source has to be considered
  • ethical issues as the use destroys embryos
  • research establishments need to be regulated
24
Q

what is the meaning of the term totipotent cell?

A

a cell that has the ability to differentiate into all cell types

25
Q

how do cells become specialised?

A
  • chemical signals cause some genes to be activated
  • only activated genes are transcribed
  • leads to synthesis of specific proteins which cause cell modification
26
Q

why can stem cells from the heart not be used to grow cells to repair the cornea?

A
  • not totipotent
  • some genes already activated and deactivated
  • so cannot specialise into cornea cells
27
Q

why does age affect the time taken to recover from injuries?

A
  • time will increase
  • due to fewer stem cells with age
  • to replace cells in tissues
28
Q

what is meant by the term stem cell?

A
  • undifferentiated cell
  • that can give rise to specialised cells
  • that can divide to produce more stem cells
29
Q

compare and contrast the results of meiosis and mitosis in the production of gametes from stem cells

A
  • both increase the number of cells
  • mitosis produces diploid, meiosis produces produces haploid
  • meiosis produces genetically different, mitosis produces genetically identical
  • mitosis results in 2 daughter cells, meiosis 4
30
Q

why may an individual have a greater adult height than their biological parents?

A
  • height is affected by environment as well as genotype
  • eg higher protein diet
  • polygenic inheritance
  • offspring can inherit a mixture of alleles from both parents
31
Q

what is the effect of Ca+ on the acrosome?

A
  • in presence, acrosome fuses w cell membrane
  • causes acrosome reaction to take place
32
Q

What is meant by the term allele?

A

Alternative form of a gene
Found at the same locus

33
Q

Explain what is meant by an inherited recessive disorder

A

Caused by a faulty allele
That is only expressed if genotype is homo recessive

34
Q

explain why sperm cells with 2 flagella may reduce fertility

A

affect motility
may prevent sperm from reaching egg
preventing fertilisation

35
Q

describe how the acrosome is involved in the digestion of the zone pellucida

A

membrane of the acrosome fuses with the plasma membrane of the sperm cell
releasing enzymes
by exocytosis

36
Q

what is the role of the acrosome?

A

to release enzymes to digest the zone pellucida

37
Q

what are the function of amyloplasts?

A

store starch granules

38
Q

how does independent assortment over produce gametes w new combos of alleles?

A

diff combos of chromosomes

39
Q

how may crossing over differ in sex chromosomes?

A

crossovers cannot form between some sections of X and Y chromosome
not homologous
Y is shorter
alleles on X that aren’t on Y

40
Q

describe how a slide can be prepared from a root tip sample

A

stained w toluidine blue
use of HCl to prepare tissue sample
tissue heated
tissue squashed under coverslip

41
Q

what stage of interphase has the greatest increase in cell size

A

G1

42
Q

describe what happens inside a cell during prophase of mitosis

A

nucleolus breaks down
centrioles move to opposite poles of the cell
to form spindle fibres
nuclear membrane breaks down
chromosomes condense

43
Q

explain why DNA is replicated before mitosis begins

A

ensure that one copy of each chromosome in each daughter cell

ensure daughter cells are genetically identical

44
Q

explain how large numbers of cells with the same phenotype can be produces in a tissue

A

phenotype determined by genotype and effect of environment

mitosis produces cells w same genotype

45
Q

name the part of a chromosome that is occupied by a gene

A

locus

46
Q

describe how each gamete receives only one allele of each gene

A

homologous chromosomes are separated

sister chromatids separated

spindle fibres pull chromosomes to opposite poles of the cell

47
Q

give the reason for the high density of mitochondria found in the mid piece of a sperm cell

A

energy/ATP for movement of flagellum

48
Q

explain why genes found on the sex chromosome pair have a pattern of inheritance that is different from genes found on other chromosome pairs

A

X chromosome carries genes not present on the Y chromosome

males have only one copy of some genes

it will be expressed

49
Q

state how a graph provides evidence that a characteristic shows polygenic inheritance

A

shows continuous variation

50
Q

what does polygenic inheritance mean

A

controlled by more than one gene

51
Q

describe how a tissue differs in structure from a system

A

tissue contains only type of cell
system contains many diff tissues/ organs

52
Q

describe how stem cells can give rise to different types of cell

A

different stimuli activate different genes

genes activated are transcribed/ mRNA produced from active genes

mRNA translated to produce proteins

proteins determine structure/ function of cells

diff genes activated/ proteins produced result in diff types of cell being produced

53
Q

explain what is meant by the phrase: the null hypothesis was rejected at the 5% significance level for this investigation

A

there is a correlation
as there is only a 5% likelihood of these results being produced by chance

bio questions (6 decks)

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