life science exam Flashcards
(114 cards)
1
Q
cell theory
A
- all cells come from pre-existing cells
- cells are the basic unit of life
- all organisms are composed of one or more cells
2
Q
prokaryote only
A
- no nucleus
- plasmids
- no membrane-bound organells
3
Q
eukaryote only
A
- has a nucleus
- - contains membrane-bound organells
4
Q
both prokaryote and eukaryote
A
- contain DNA
- contain ribosomes
- cytoplasm
- cell membrane
5
Q
cell wall
A
protects the cell –> plant only
6
Q
large vacuole
A
stores water, nutrients, and waste –> plant only
7
Q
chloroplast
A
site of photosynthesis –> plant only
8
Q
nucleus
A
controls cell activity and contains DNA
9
Q
smooth ER
A
produces lipids
10
Q
rough ER
A
transports proteins, protein synthesis
11
Q
ribosomes
A
protein synthesis
12
Q
mitochondria
A
produces ATP, cellular respiration (the squiggly one)
13
Q
golgi apparatus
A
stores, modifies, and transports protiens
14
Q
cell membrane
A
allows for certain substances to enter and exit the cell
15
Q
cytoplasm
A
provides structure and holds organelles in place
16
Q
lysosome
A
digests and recycles waste –> plant only
17
Q
DNA
A
deoxyribonucleic acid: chemical component found in the nucleus that stores coded instructions. Has the code for different proteins and cells
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
19
Q
nucleotides
A
the basic structure of DNA
- deoxyribose sugar (the pentagon)
- phosphate (the small circle, LINK phosphate cycle)
- nitrogenous bases (rectangle)
20
Q
chromosome
A
a thread like strand of DNA that is encoded with genes. humans have 46 chromosomes in each cell (23 pairs)
21
Q
homologous chromosomes
A
similar in length, centromere position, banding pattern. one is inherited from mother, and one from father
22
Q
karyotype
A
a picture of homologous chromosomes arranged from largest to smallest
23
Q
down syndrome
A
three chromosomes at number 21
24
Q
turners syndrome
A
only one sex chromosome
25
kleinfelters syndrome
three sex chromosomes
26
gene
a section of DNA containing instructions and codes which produce specific proteins
27
RNA
ribonucleic acid
28
characteristics of RNA
- - single stranded
- - contains uracil (U)
- - ribose sugar
29
characteristics of DNA
- - double-stranded
- - contains thymine (T)
- - deoxyribose sugar
30
transcription
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
31
translation
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.
32
importance of the cell cycle
important for growth, repair, development, maintenance of cells
33
mitosis
1 cell division, 2 daughter cells, one parent cell, 46 chromosomes, diploid, somatic (body) cell, genetically identical
34
meiosis
2 cell divisions, 1 parent cell, 4 daughter cells, 23 chromosomes, haploid, gamete, genetically different
35
genotype
genetic makeup of an individual
36
phenotype
physical expression of a geneotype within an environment
37
apoptosis
programmed cell death
38
interphase
DNA replicates, chromosomes are not visible, longest stage of the cell cycle
39
prophase
chromosomes condense, spindle fibres form, nuclear membrane breaks down
40
metaphase
chromosomes line up along the midline of the cell
41
anaphase
sister chromatids separate to opposite ends of the cell
42
telophase
new nuclear membrane forms, spindle fibres disappear, chromosomes decondense
43
cytokinesis
division of cytoplasm into 2 genetically identical daughter cells.
44
allele
different versions of the same gene
45
homozygous
two of the same alleles of a gene eg bb or BB
46
heterozygous
two different alleles of the same gene eg. Bb
47
dominant
trait will always be expressed
48
recessive
traits will only be expressed if there is two
49
codominance
when two alleles are equally expressed
50
sex linked genes
carried on the X and Y chromosomes. Most traits are on the X chromosome as it is much larger.
51
steps to looking at a pedigree
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
mutation
changes that occur at the DNA level that are inheritable. Caused by chance, cell division error, or from a mutagen
53
mutagen
chemical or physical agents that can cause a mutation to DNA
54
gametic mutation
occurs in testes and ovaries. it is inherited and can be passed to offspring
55
somatic mutation
occur in body cells. they are not inherited but may affect the person during their lifetime
56
gene mutations
occur when nitrogenous base is inserted, deleted, or rearranged
57
point mutation
one base is substituted for another. codes for the wrong amino acid resulting in a faulty protein
58
frameshift mutation
a base has been inserted or deleted. results in a non-functional protein
59
chromosomal mutations
occur due to non-disjunction --> when chromosomes don't separate correctly during meiosis.
60
natural selection
selects for adaptations that allow for an organism to survive and reproduce
61
natural selection steps
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
selection pressures
predators, food source, climate
63
gene pool
all of the different genes in a population
64
variation
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
speciation
the process of forming a new species
66
steps in speciation
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
allopatric speciation
populations become geographically isolated and each population faces different natural selection pressures
68
geographical isolation
a geographical barrier that stops gene flow between isolated populations
69
temporal isolation
species mate at different times
70
behavioural isolation
animals have different mating behaviours
71
mechanical isolation
animals have different sized body parts = no gene flow = no babies
72
divergent evolution
when two or more species sharing a common ancestor become less alike overtime
73
homologous structures
structures evolved from a common ancestor but now perform different functions
74
convergent evolution
unrelated organisms independently evolve similarities when adapting to similar environments
75
analogous structures
animal structures that perform similar functions but arent closely related
76
artificial selection
selects adaptations or traits for the benefit of humans
77
fossils
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
transitional fossil
shows the intermediate state between ancestral form and that of the decendents
79
comparing DNA
organisms closely related have a higher percentage of DNA / genes in common
80
Comparing proteins
comparing the sequence of amino acids in a protein. can show the evolutionary relationship between species.
81
comparing embryology
study of the development in the structure and function of embryos
82
comparative anatomy
comparing physical structures found in organisms
83
vestigial structures
functionless structures found in organisms eg. wisdom teeth
84
biogeography
the study of how continents move and the impact on the location of organisms
85
lithosphere
describes the rocks, minerals, and molten magma found on earth
86
hydrosphere
all water on earth
87
atmosphere
the layer of gases surrounding the earth.
88
biosphere
composed of all organisms on the planet
89
oxygen cycle
oxygen is essential for life. It is produced by photosynthesis and is a reactant in cellular respiration --> used to create ATP.
90
photolysis
UV light splits water into hydrogen and oxygen (in the atmosphere
91
nitrogen cycle
a part of RNA, DNA and proteins.
92
nitrogen fixation
some bacteria convert nitrogen into nitrates or nitrites which is a usable form of nitrogen. Lightning can also fix.
93
phosphorus cycle
important for DNA, RNA, ATP.
94
eutrophication
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
water cycle
essential for photosynthesis and cellular respiration and all living things need water. water cycles between the four spheres
96
transpiration
water is transferred from below the ground to the air by plants
97
carbon cycle
keeps carbon levels naturally balanced. earth would become inhabitable without it. Removed by photosynthesis and released by cellular respiration, fossil fuels, decomposition etc.
98
carbon sinks
where carbon is stored away from the atmosphere
| eg. forests, oceans, rocks, organic matter in soil
99
the greenhouse effect
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
greenhouse gases
help to retain heat on the earth
101
enhanced greenhouse effect
increased level of global warming caused by the increase of greenhouse gases in the atmosphere, trapping more heat energy
102
pollution
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
contamination
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
pollution vs contamination
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
waste
a material, substance, or by-product eliminated or discarded as it is no longer useful or required.
106
air pollution
harmful compounds get mixed with the atmosphere leading to depletion of the ozone layer and respiratory problems
107
water pollution
discharge or spillage of waste into different bodies of water
108
soil pollution
pesticides get mixed with soil and lessens its fertility
109
light pollution
bright lights result in astronomical interference and over-illumination
110
noise pollution
harmful noise may result in auditory problems as well as psychological issues
111
point source
able to point directly to the source of pollution
| -- a factory releasing mercury into a river
112
non-point source
no single location is the point of origin
| -- runoff of stormwater containing fertiliser
113
coral bleaching
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
gel electrophoresis
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.
