MODULE 4 Flashcards
the basic unit of life
Cell
smallest structure that exhibits almost all known properties or
attributes of being alive
cell
cells arise from the
division of other pre-existing cells
cell theory
two cell cycle
mitosis and meiosis
process where cell grows, synthesize
mRNA and proteins
Gap phase 1 (G1)
DNA synthesis occurs
S (synthesis) phase
cell continues to grow further; makes proteins and organelles (i.e.
centrosomes); cell reorganizes its contents as
preparation
G2 phase
DNA wraps around
histones to develop a more compact
shape
chromosome
same
genetic information
sister chromatids
useful for equal
separation
kinetochore
holds the sister
chromatids together
centromere
produces microtubules
centrosome
DNA starts to condense; from chromatins into
chromosomes and centrosomes extend their microtubules
Prophase
late prophase
prometaphase
nuclear envelope starts to break apart;
extending microtubules attaches to the kinetochore
prometaphase
chromosomes lines up in the middle along the mitotic plate
metaphase
chromosomes move apart;
each sister chromatid have the same genetic information content;
resulting chromatids, now called chromosomes, move at the end of each pole
anaphase
chromosomes pulled to the opposite ends of the cell
telophase
chromosomes decondense; mitotic spindle breaks
down, nuclear membranes reform
telophase
nucleus is formed
telophase
cleavage furrow separates the cell into two daughter cells
cytokinesis
overlaps with anaphase and telophase
cytokinesis
resting phase
G0 phase
cellular state outside the repetitive cell cycle;
cells no longer need to divide or have not
received any signals that they must divide
nerve cells and heart cells no longer need to
divide again
G0 phase
produce 2 identical daughter cells
mitosis
cell divides twice to produce four
cells containing half the original amount of
genetic information
meiosis
destined to be sex cells/gametes/sperm and egg
meiosis
chromosomes undergo synapsis - chromosomes
from mother and father are coming together,
wrapping around each other
prophase 1
crossing over occurs - the lined up
chromosomes exchange some segments of their
chromosomes
prophase 1
homologous chromosomes line up in the middle
metaphase 1
homologous chromosomes line up in the middle
metaphase 1
mitotic spindle attaches to the centromere of the
homologous chromosomes
metaphase 1
chromosomes are pulled apart; migrate to opposite
poles
anaphase 1
new nuclei are formed in each side of the pole; whole cell is fully divided
telophase 1 and cytokinesis
chromosomes condense again
nuclear membrane breaks down
new set of mitotic spindle forms; no crossing over
prophase 2
four haploid cells created
nuclear membrane reforms; spindle fibers
disappear
telophase 2 and cytokinesis 2
division of body cells
mitosis
division of sex cells
meiosis
division of cell occurs once
mitosis
division of cell occurs twice
meiosis
two daughter cells are produced
mitosis
four daughter cells are produced
meiosis
daughter cells resulting from mitosis
diploid
daughter cells resulting from meiosis
haploid
daughter cells produced are genetically identical
mitosis
daughter cells produced are genetically diverse
meiosis
difference between mitosis and meiosis
Mitosis involves the division of body cells, while meiosis involves the division of sex cells.
The division of a cell occurs once in mitosis but twice in meiosis.
Two daughter cells are produced after mitosis and cytoplasmic division, while four daughter cells are produced after meiosis.
Daughter cells resulting from mitosis are diploid, while those resulting from meiosis are haploid.
Daughter cells that are the product of mitosis are genetically identical. Daughter cells produced after meiosis are genetically diverse.
first possible error occurs in meiosis 1
when homologous chromosomes
fail to separate; one cell is produced with both
homologs; results in trisomy and monosomy
second possible error in meiosis 2
if a sister chromatid fails to
separate
results to 2 abnormal cells
observed in green algae
haplontic life cycle
haplontic life cycle is called
zygotic meiosis
Fusion of gametes to produce the diploid zygote
haplontic life cycle
observed in humans and seed bearing plants; majority plants and animals
diplontic life cycle
what is haploid
contains a single set of chromosomes
what is diploid
two sets of chromosomes
zygote grows by mitosis to form a fully functional multicellular organism
diplontic life cycle
a gamete can unite with another one and form a diploid zygote
diplontic life cycle
Alternation of generations
haplodiplontic or diplohaplontic life cycle
diploid zygote grows by mitosis to become the multicellular sporophyte
sporophytic generation
asexual phase of haplodiplontic cycle
sporophytic generation
sexual phase of haplodiplontic cycle
gametophytic generation
produces gametes by mitosis -> fuse to form diploid zygote
gametophytic generation
“The only method that will allow a co-evolving species to maintain its own share of the resources is to also continually improve its fitness”
red queen hypothesis
units of information about specific traits; segment of DNA that codes for a particular trait
genes
different molecular forms of a gene/sequence
alleles
usually masks a recessive allele that is paired with it
dominant allele
will only manifest if in the
homozygous condition
recessive allele
having 2 identical alleles at a locus (BB or bb)
homozygous
having 2 different alleles at a locus (Bb)
heterozygous
particular genes in individual carriers; genetic information
genotype
individual’s observable traits
phenotype
an individual inherits a unit of information (allele) about a trait from each parent
mendel’s principle of segregation
genetic mix between two F1 heterozygotes
monohybrid cross
between individuals that are homozygous for different versions of two traits
dihybrid cross
the random orientation of homologous chromosome pairs during metaphase I (this is only true for genes that are on different chromosomes)
mendel’s principle of independent assortment
two true-breeding parents crossed to produce an intermediate offspring (also known as heterozygous)
incomplete dominance
the variants (alleles) are not expressed as dominant or recessive; rather, the dominant allele is expressed in a reduced ratio
incomplete dominance
Two alleles (IA and IB) are codominant when paired
codominance
Single gene may have phenotypic effects (sickle cell diseases caused by an allele at the gene for hemoglobin)
pleiotropy
dili sya completely makadominate; ang offspring is mixed
incomplete dominance
mushow sila both
codominance
1 gene equals to many trait
pleiotropy
many genes interact with each other and with the environment to influence a single trait
polygenic inheritance
entirely linked on the x or y chromosome
sex-linked genes
if female, dapat both dominant pala mushow; if male, kahit usa ra ang dominant mushow ghapon
sex influenced traits
affect the shape of the red blood cell, this defect causes physical weakness, heart failure, impaired mental function, pneumonia, rheumatism, and kidney failure
pleiotropy
the greater the number of genes and environmental factors that affect a trait, the more continuous the variation in versions of that trait
polygenic inheritance
many influencers to a single trait
polygenic inheritance
some human traits occur as a few discrete types
human variation
traits whose genes are found in the X or Y chromosome only
sex linked genes
a serious X-linked recessive condition - inability of the blood to clot because the gene does not code for the necessary clotting agents
hemophilia A
genes found only on the Y chromosome
y-linked (holandric)
will manifest only in males since they are the ones with the Y chromosome
y-linked (holandric)
Traits can be expressed genotypically in the homozygous or heterozygous conditions but the expression of dominance is affected by the sex of the individual involved
sex influenced traits
offspring will have hereditary material uniform with the hereditary material of the parent organism - will be genetically alike unless mutation occurs
asexual reproduction
a new duplicate plant or animal begins to form at the side of the parent and enlarges until an individual is created
budding
the ability to restore lost or damaged tissues, organs, or limbs
regeneration
a type of cell division where one organism becomes 2 complete organisms (binary and transverse)
fission
An unfertilized egg develops into an adult animal
pathogenesis
Asexual plant propagation methods that produce new plants from the vegetative parts of the original plant, such as the leaves, stems, and roots
vegetative propagation
Parent plant produces hundreds of tiny spores which can grow into new organisms
spore formation
Widespread occurrence ranging from the simplest to the most complex of organisms
sexual production
hermaproditic
monoecious reproduction
both male and female gonads can be found in only one organism
monoecious reproduction
fusion of gametes
fertilization
an organism have the male and female reproductive organs in separate individuals
dioecious reproduction
gametes meet outside the parent’s body with or without physical contact; gametes are released into the water simultaneously
external fertilization
union of egg and sperm occurs within the body of the female
internal fertilization
protandrous species develop first as males but could become females
gender bending
sex reversal
gender bending
sequential hermaproditism
gender bending
COURTSHIP FOR SUCCESSFUL MATING
Visual and ritual displays, bringing gifts, fighting for the female
Certain ecological principles govern the growth and sustainability of all populations including human population
population ecology
a group of individuals of the same species occupying a given area
population
size or count of the population
population in terms of numbers
no. of individuals/area
population in terms of density
spatial relationship between members of a population within a habitat
distribution or dispersion
proportionate numbers of people in different age categories for a defined time
age structure
number of individuals added through reproduction
natality
the study of the size and distribution of biodiversity over space and time
biogeography
the study of the vital statistics that affect population size
demography
births per 1000
crude birth rate
average number of children born alive per woman in her lifetime
total fertility rate
death per 100
crude death rate
number of individuals removed through death
mortality
Number of individuals in a specific area (or volume) of habitat (i.e. individuals/km km2; individuals/ml)
density
involves no further clarifications, no idea how many males or females; no info on how many are in the pre-reproductive category
crude density
the most common type where more individuals will be present in areas that are favorable to them
clumped
May happen when there is competitive interactions between individuals
uniform
Occurs when there is less competition due to availability of resources
random
limiting factors become more intense as population size increases; usually biological in nature
density dependent
factors unaffected by population density; usually physical in nature
density independent
population size increase
through births (B) and immigration (I)
population size decrease
through deaths (D) and emigration (E)
No. of years by which a population doubles; calculate the doubling time for a population in years
rule of 70
Result of interaction between natality (birth) and mortality (death) showing the population profile–growth or decline in populations in various age classes
population age structure
intrinsic rate of increase (r) is the rate at which a population would grow if it had unlimited resources (maximum rate of increase per individual under conditions with no environmental pressures to the population)
biotic potential
K = max number of individuals that can be sustained in a particular habitat
carrying capacity
give 5 environmental resistance
Decreasing O2 supply
Lack of food, water, suitable habitat
Adverse weather conditions
Disease, Predators, parasites, competitors
Patterns of timing of reproduction and survivorship
survivorship curves
survivorship curve from late loss
type 1
survivorship curve from early loss
type 3
survivorship curve from constant loss
type 2
Rectangular survivorship on semilogarithmic plot:
little mortality until old age, then fairly steep
mortality
type 1
Diagonal line: relatively constant death rates
with age
type 2
Inverse hyperbolic: extremely steep juvenile
mortality, then relatively high survivorship
afterward
type 3
discrete heritable units that are
passed on from parent to offspring
genes
alternative forms of the same
gene; found in chromosomes
alleles
has no noticeable effect in the presence of the dominant
allele
recessive allele
have short stature, with an average adult
height of 4 feet, 3.8 inches for males and 4
feet, 0.6 inches for females
Achondroplasia
a congenital physical anomaly in humans, dogs, cats and having supernumerary fingers or toes
polydactyly
the complete set of genetic
information contained within the
individuals in a population
gene pool
a real population must be compared with an
idealized population where the allelic frequencies do
not change
hardy-weinberg principle
implications of hardy-weinberg law
A population CANNOT evolve if it meets the Hardy-Weinberg assumption
when a population is in HWE, the genotypic frequencies are determined by the
allelic frequencies
assumptions
- diploid organism
- sexual reproduction
- non-overlapping generations
- random mating
- large population size
- equal allele frequencies in the sexes
- no migration
- no mutation
- no selection
real populations are rarely at Hardy-Weinberg equilibrium, so their allele frequencies change, which lead to evolution
- mutation
- genetic drift
- migration
- natural selection
- non-random mating
may be neutral, detrimental or advantageous,
depending on the environment (environmental
changes may favor different alleles than those
previously favored)
mutation
when the frequency of an existing gene variant in the population changes due to
random chance
genetic drift
Factors that Cause Genetic Drift
bottleneck effect and founder effect
a drastic reduction in population (caused by volcanic eruptions, earthquakes,
landslides, etc.)
bottleneck effect
occurs when a new colony is started by a few members of the original population
founder effect
gene movement and is referred to as gene flow
migration
two major effects on a population of gene flow
- May introduce new alleles to a population
- When migrants have different allelic frequency than recipient population, allelic
frequencies will be altered in the recipient population
Success in reproduction based on heritable traits
results in selected alleles being passed to
relatively more offspring (Darwinian inheritance
natural selection
effects over vast spans of time, can produce
new species from ancestral species
natural selection
when a particular phenotype is preferred in mates, genotype frequencies will be affected
non-random mating
mating occurs when
individuals with similar phenotypes mate
preferentially
positive assortative
mating occurs when
phenotypically dissimilar individuals mate
preferentially
negative assortative
occurs when closely related individuals
mate with each other
inbreeding
