life science exam Flashcards

1
Q

cell theory

A
  1. all cells come from pre-existing cells
  2. cells are the basic unit of life
  3. all organisms are composed of one or more cells
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2
Q

prokaryote only

A
    • no nucleus
    • plasmids
    • no membrane-bound organells
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3
Q

eukaryote only

A
    • has a nucleus

- - contains membrane-bound organells

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4
Q

both prokaryote and eukaryote

A
    • contain DNA
    • contain ribosomes
    • cytoplasm
    • cell membrane
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5
Q

cell wall

A

protects the cell –> plant only

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6
Q

large vacuole

A

stores water, nutrients, and waste –> plant only

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7
Q

chloroplast

A

site of photosynthesis –> plant only

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8
Q

nucleus

A

controls cell activity and contains DNA

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9
Q

smooth ER

A

produces lipids

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10
Q

rough ER

A

transports proteins, protein synthesis

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11
Q

ribosomes

A

protein synthesis

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12
Q

mitochondria

A

produces ATP, cellular respiration (the squiggly one)

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13
Q

golgi apparatus

A

stores, modifies, and transports protiens

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14
Q

cell membrane

A

allows for certain substances to enter and exit the cell

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15
Q

cytoplasm

A

provides structure and holds organelles in place

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16
Q

lysosome

A

digests and recycles waste –> plant only

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17
Q

DNA

A

deoxyribonucleic acid: chemical component found in the nucleus that stores coded instructions. Has the code for different proteins and cells

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18
Q

structure of DNA

A

DNA is a double helix and is said to be anti-parallel. Held together by hydrogen bonds between base pairs

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19
Q

nucleotides

A

the basic structure of DNA

  1. deoxyribose sugar (the pentagon)
  2. phosphate (the small circle, LINK phosphate cycle)
  3. nitrogenous bases (rectangle)
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20
Q

chromosome

A

a thread like strand of DNA that is encoded with genes. humans have 46 chromosomes in each cell (23 pairs)

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21
Q

homologous chromosomes

A

similar in length, centromere position, banding pattern. one is inherited from mother, and one from father

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22
Q

karyotype

A

a picture of homologous chromosomes arranged from largest to smallest

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23
Q

down syndrome

A

three chromosomes at number 21

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24
Q

turners syndrome

A

only one sex chromosome

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25
Q

kleinfelters syndrome

A

three sex chromosomes

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26
Q

gene

A

a section of DNA containing instructions and codes which produce specific proteins

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27
Q

RNA

A

ribonucleic acid

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28
Q

characteristics of RNA

A
    • single stranded
    • contains uracil (U)
    • ribose sugar
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29
Q

characteristics of DNA

A
    • double-stranded
    • contains thymine (T)
    • deoxyribose sugar
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30
Q

transcription

A

occurs in the nucleus

  1. DNA unwinds to expose bases
  2. Free mRNA strands bind following complimentary base pairing rules
  3. mRNA strand is produced
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31
Q

translation

A

occurs in the cytoplasm

  1. mRNA attaches to a ribosome in the cytoplasm
  2. tRNA brings specific amino acids to the ribosome
  3. amino acids are joined together via a peptide bond and a protein is formed.
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32
Q

importance of the cell cycle

A

important for growth, repair, development, maintenance of cells

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33
Q

mitosis

A

1 cell division, 2 daughter cells, one parent cell, 46 chromosomes, diploid, somatic (body) cell, genetically identical

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34
Q

meiosis

A

2 cell divisions, 1 parent cell, 4 daughter cells, 23 chromosomes, haploid, gamete, genetically different

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35
Q

genotype

A

genetic makeup of an individual

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36
Q

phenotype

A

physical expression of a geneotype within an environment

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37
Q

apoptosis

A

programmed cell death

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38
Q

interphase

A

DNA replicates, chromosomes are not visible, longest stage of the cell cycle

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39
Q

prophase

A

chromosomes condense, spindle fibres form, nuclear membrane breaks down

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40
Q

metaphase

A

chromosomes line up along the midline of the cell

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41
Q

anaphase

A

sister chromatids separate to opposite ends of the cell

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42
Q

telophase

A

new nuclear membrane forms, spindle fibres disappear, chromosomes decondense

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43
Q

cytokinesis

A

division of cytoplasm into 2 genetically identical daughter cells.

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44
Q

allele

A

different versions of the same gene

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45
Q

homozygous

A

two of the same alleles of a gene eg bb or BB

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46
Q

heterozygous

A

two different alleles of the same gene eg. Bb

47
Q

dominant

A

trait will always be expressed

48
Q

recessive

A

traits will only be expressed if there is two

49
Q

codominance

A

when two alleles are equally expressed

50
Q

sex linked genes

A

carried on the X and Y chromosomes. Most traits are on the X chromosome as it is much larger.

51
Q

steps to looking at a pedigree

A
  1. is the trait dominant or recessive?
    – do all affected individuals have at least one affected parent
    yes = dominant
    no = recessive
  2. is the trait sex-linked or recessive?
    – DOMINANT: do all affected males have affected mothers and all affected daughters?
    —- yes = X linked dominant
    —- no = autosomal dominant
    – RECESSIVE: do all affected females have affected fathers and all affected sons?
    —- yes = x linked recessive
    —- no = autosomal recessive

OR: autosomal = number of males and females affected is similar
X linked dominant = greater number of females effected
X linked recessive = greater number of males affected.

52
Q

mutation

A

changes that occur at the DNA level that are inheritable. Caused by chance, cell division error, or from a mutagen

53
Q

mutagen

A

chemical or physical agents that can cause a mutation to DNA

54
Q

gametic mutation

A

occurs in testes and ovaries. it is inherited and can be passed to offspring

55
Q

somatic mutation

A

occur in body cells. they are not inherited but may affect the person during their lifetime

56
Q

gene mutations

A

occur when nitrogenous base is inserted, deleted, or rearranged

57
Q

point mutation

A

one base is substituted for another. codes for the wrong amino acid resulting in a faulty protein

58
Q

frameshift mutation

A

a base has been inserted or deleted. results in a non-functional protein

59
Q

chromosomal mutations

A

occur due to non-disjunction –> when chromosomes don’t separate correctly during meiosis.

60
Q

natural selection

A

selects for adaptations that allow for an organism to survive and reproduce

61
Q

natural selection steps

A
  1. there is variation among species
  2. not all of the population survived (who did)
  3. those that survived reproduced
  4. overtime genes are passed to offspring
62
Q

selection pressures

A

predators, food source, climate

63
Q

gene pool

A

all of the different genes in a population

64
Q

variation

A

within a species, there is variation in the gene pool. Individuals have the same number of genes but different alleles. variation (new alleles) arise from mutations

65
Q

speciation

A

the process of forming a new species

66
Q

steps in speciation

A
  1. species are isolated
  2. populations face different selection pressures and have adapted through natural selection
  3. become reproductively isolated from each other and are considered separate species
67
Q

allopatric speciation

A

populations become geographically isolated and each population faces different natural selection pressures

68
Q

geographical isolation

A

a geographical barrier that stops gene flow between isolated populations

69
Q

temporal isolation

A

species mate at different times

70
Q

behavioural isolation

A

animals have different mating behaviours

71
Q

mechanical isolation

A

animals have different sized body parts = no gene flow = no babies

72
Q

divergent evolution

A

when two or more species sharing a common ancestor become less alike overtime

73
Q

homologous structures

A

structures evolved from a common ancestor but now perform different functions

74
Q

convergent evolution

A

unrelated organisms independently evolve similarities when adapting to similar environments

75
Q

analogous structures

A

animal structures that perform similar functions but arent closely related

76
Q

artificial selection

A

selects adaptations or traits for the benefit of humans

77
Q

fossils

A

remains / traces of an organism embedded into the earth. for a fossil to be formed, it must first be buried before it decomposes. bones are the most common thing found in fossils as they take the longest to decompose

78
Q

transitional fossil

A

shows the intermediate state between ancestral form and that of the decendents

79
Q

comparing DNA

A

organisms closely related have a higher percentage of DNA / genes in common

80
Q

Comparing proteins

A

comparing the sequence of amino acids in a protein. can show the evolutionary relationship between species.

81
Q

comparing embryology

A

study of the development in the structure and function of embryos

82
Q

comparative anatomy

A

comparing physical structures found in organisms

83
Q

vestigial structures

A

functionless structures found in organisms eg. wisdom teeth

84
Q

biogeography

A

the study of how continents move and the impact on the location of organisms

85
Q

lithosphere

A

describes the rocks, minerals, and molten magma found on earth

86
Q

hydrosphere

A

all water on earth

87
Q

atmosphere

A

the layer of gases surrounding the earth.

88
Q

biosphere

A

composed of all organisms on the planet

89
Q

oxygen cycle

A

oxygen is essential for life. It is produced by photosynthesis and is a reactant in cellular respiration –> used to create ATP.

90
Q

photolysis

A

UV light splits water into hydrogen and oxygen (in the atmosphere

91
Q

nitrogen cycle

A

a part of RNA, DNA and proteins.

92
Q

nitrogen fixation

A

some bacteria convert nitrogen into nitrates or nitrites which is a usable form of nitrogen. Lightning can also fix.

93
Q

phosphorus cycle

A

important for DNA, RNA, ATP.

94
Q

eutrophication

A

dishwashing detergent and soil from farms contain phosphorus. run off from drains and farmlands increase the level of phosphorus within waterways. Increased phosphorus causes algal blooms, which block sunlight and halt photosynthesis. It also increases the levels of bacteria that take all of the oxygen from marine animals.

95
Q

water cycle

A

essential for photosynthesis and cellular respiration and all living things need water. water cycles between the four spheres

96
Q

transpiration

A

water is transferred from below the ground to the air by plants

97
Q

carbon cycle

A

keeps carbon levels naturally balanced. earth would become inhabitable without it. Removed by photosynthesis and released by cellular respiration, fossil fuels, decomposition etc.

98
Q

carbon sinks

A

where carbon is stored away from the atmosphere

eg. forests, oceans, rocks, organic matter in soil

99
Q

the greenhouse effect

A

natural phenomena critical for life on earth. Some solar energy from the sun is trapped by gasses in the atmosphere and some is radiated into space = ideal temperature on earth.

100
Q

greenhouse gases

A

help to retain heat on the earth

101
Q

enhanced greenhouse effect

A

increased level of global warming caused by the increase of greenhouse gases in the atmosphere, trapping more heat energy

102
Q

pollution

A

the addition of a substance into an environment by human activity, at a rate greater than can be rendered harmless by the environment and the organisms that live in it

103
Q

contamination

A

where an external mixture gets mixed with the original matter. may be chemical, biological, or radioactive in nature. may or may not be harmful to the environment.

104
Q

pollution vs contamination

A

pollution is harmful, contamination is not. You can have a contaminated environment without it being polluted, but it cannot be polluted without being contaminated. pollutants can be either foreign substances or a component of the original substance that has exceeded the harmless level.

105
Q

waste

A

a material, substance, or by-product eliminated or discarded as it is no longer useful or required.

106
Q

air pollution

A

harmful compounds get mixed with the atmosphere leading to depletion of the ozone layer and respiratory problems

107
Q

water pollution

A

discharge or spillage of waste into different bodies of water

108
Q

soil pollution

A

pesticides get mixed with soil and lessens its fertility

109
Q

light pollution

A

bright lights result in astronomical interference and over-illumination

110
Q

noise pollution

A

harmful noise may result in auditory problems as well as psychological issues

111
Q

point source

A

able to point directly to the source of pollution

– a factory releasing mercury into a river

112
Q

non-point source

A

no single location is the point of origin

– runoff of stormwater containing fertiliser

113
Q

coral bleaching

A

where coral dies as protists living inside them can no longer perform photosynthesis = loss of colour and the coral’s death. warmer conditions make the coral stressed and they release the protists living on them.

114
Q

gel electrophoresis

A
  1. DNA is collected and isolated
  2. DNA is fragmented into short lengths
  3. DNA is inserted into the gel with a micropipette
  4. electric current is run through gel
  5. DNA moves toward the positive electrode
  6. smallest fragment moves furthest away from well
  7. DNA pattern is compared with other samples.