Biology 1 Flashcards
What is a heterotroph
something that is dependent on outside sources for food
What is the heterotroph hypothesis
- salts, methane, ammonia, water
- combined with energy from sun
- Made (sugar, amino acids, nucleotides)
- Called the primordial soup
- these combined to form macromolecules
what is a coacervate droplet
a cluster of collodial molecules surrounded by a shell of water. they could absorb and metabolize materials
what did these coacervate droplets turn into
the first primitive cells capable of reproduction
What was the problem with some of the first heterotrophs
they were using energy faster than they could get it
what are autotrophs
organisms that could provide their own energy
What did the autotrophs do to the ozone
they fixed CO2 and released O2, this changed it from a reducing atmosphere to an oxidizing one.
What is an autotrophic anaerobe
chemosynthetic bacteria
What is an autotrophic aerobe
green plants and photo plankton
What is a heterotrophic anaerobe
yeast
what is a heterotrophic aerobe
ameobas, earthworms and humans
what is the protoplasm
the important elements and minerals that make up the substance of life
What is the ratio of carbon, hydrogen, and oxygen in CARBS
1:2:1
what reactions join disaccharides
dehydration synthesis
what classifies a dehydration reaction
water leaves
what reactions break down polysaccharides
hydrolysis
What is the ratio of H:O
much more that 2:1
what types of reactions attach fatty acids to glycerol
dehydration
What is a phospholipid
a glycerol with two fatty acids a phosphate group and a nitrogen containing alcohol.
What is lecithin
a phospholipid a major constituent of cell membranes
What are some examples of phospholipids
lecithin
cephalin
What is cephalin
found in the brain, nerves, and neural tissues
What are waxes
esters of fatty acids and monohydroxylic alcohols
Where are waxes found
protective coatings of skin fur leaves of higher plants exoskeleton of many insects
What are steroids
three fused cycloheaxane rings and a cyclopentane ring
What are some steroids
cholesterol sex hormones testosterone estrogen corticosteroids
What are carotenoids
fatty acid-like carbon chains with conjugated double bonds, and carrying six membered carbon rings at each end.
What do caretenoids do
they are the pigment that produce red, yellow, orange, and brown in plants and animals
What are the subgroups of carotenoids
carotenes
xanthophylls
What are porphyrins
molecules with four joined pyrrole rings, often complexed with metal.
What is another name for porphyrins
tetrapyrroles
What is an example of a porphyrin
heme complex with Fe in hemoglobin
chlorophyll complexed with Mg
What are proteins
polymers of amino acids
What are the bonds between amino acids
peptide bonds
how are peptide bonds formed
dehydration reaction
What makes protein primary structure
the sequence of amino acids
What makes protein secondary structures
The regional folding of a polypeptide
What are examples of protein secondary structures
a helix
b sheet
What can proteins be classified by
structure
function
What are simple proteins
proteins made only of amino acids
what are albumins and globulins
globular proteins that act as carriers or enzymes
they are usually found in the serum
What are scleroproteins
fibrous proteins that acts as structural proteins
Collagen
What are conjugated proteins
they are proteins with a simple proteins portion and at least one non-protein fraction
what are lipoproteins
proteins bound to a lipid
what are mucoproteins
proteins bound to carbs
what are chromoproteins
proteins bound to pigmented molecules
what are metalloproteins
proteins complexed with a metal ion
What are nucleoproteins
proteins bound to nucleic acids (DNA/RNA)
in DNA it’s bound to histone or protamine
What are proteinhormones
proteins that acts as chemical messengers secreted into the blood
Insulin and ACTH
What are enzymes
biological catalysts that increase the rate of reaction
amylase, lipase ATPase
What are structural proteins
they participate in the physical support of cells or tissues
Extracellular (collagen, bone, tendons)
Intracellular (cell membrane proteins)
What are transport proteins
hemoglobin
cytochromes
What are antibodies
these bind to foreign bodies (antibodies) and start the chain of events to protect against them
What are coenzymes
often non protein things that help in catabolism
What is the lock and key theory of enzymes
active site is structurally complimentary to the substrate
What is the induced fit theory of enzymes
the active site has flexability of shape, as the substrate gets near the active site changes shape and accepts the substrate
Can enzymes work reversably
yep
What is the effect of temperature on enzyme action
increase in temperature increases rate of enzyme reaction
What is the optimal temperature for enzyme action
40 degrees celcius
What is the maximal pH for enzymes
7.2
what are some protein that like acidic conditions
pepsin (pH=2) stomach
What are some proteins that like basic conditions
pancreatic enzymes which work in the small intestine (pH=8.5)
What is the effect of concentration on enzymes
the higher the concentrations of Enzymes and substrates the higher the reaction rate, until it has reached Vmax
What is hydrolysis (enzyme)
reactions that digest large molecules into smaller components
What are some hydrolysis enzymes
lactase
proteasess
lipases
What is synthesis (enzyme)
enzyme reactions that build things up
What are cofactors
non-protein molecules that are required by enzymes for the enzymes to work
What are examples of cofactors
Zn, Fe
What are prosthetic groups for enzymes
cofactors that are covalently bound to the enzyme
What are nucleic acids
they are polymers of nucleotides.
DNA/RNA
What are nucleotides made up of
a base, sugar, and phosphate group
Summary of the cell theory
- all livings things are composed of cells
- cells are the basic functional unit of life
- cells arise only from pre-existing cells
- cells carry genetic info in the form of DNA, this is passed on from parent to daughter during division
- energy flow occurs within cells
what is a compound light microscope
a microscope with two lenses that is used to observe non-living specimen. (staining leads to cell death)
What is phase contrast microscopy
a type of microscope used to observe living specimen
What is an electron microscope
a way using electrons to get even higher magnification than the others. It can’t be used on living specimen either
Cell Membrane
- exhitibs selective permiability
- phospholipid bilayer
- permeable to small, non polar molecules
Nucleus
- houses DNA held by histones to form chromosomes
- nucleolus (where rRNA synthesis occurs
- surrounded b a nuclear membrane
Ribosome
- protein production
- found in the cytoplasm
- found on the endoplasmic reticulum
Endoplasmic reticulum
- Transport of materials throughout the cell
- packages materials to be secreted from the cell
- Smooth and rough (Ribosomes)
Golgi apparatus
- recieves vesicles from the smooth ER
- modifies vesicles with glycosylation, and repackages them
- pushes them to the cell surface by exocytosis
Mitochondria
1, site of aerobic respiration
- suppliers of energy
- inner and outer phospholipid bilayer
Cytoplasm
- The jelly of the cell
- most of the cells metabolic activity occurs here
- transport within the cell happens by cyclosis
Vacuole
- membrane bound sacs involved in transport of materials
- larger than vesicles
- more likely found in plant cells than animals cells
Centrioles
- microtubule involved in spindle organization during cell division
- plants don’t have them
- in animals cells they are opposite eachother in the centrosome
Lysosome
- membrane bound vesicles with hydrolytic enzymes
- break down things ingested by the cell
- cells commit suicide by rupturing the lysosome (autolysis)
Cytoskeleton
- made of microtubules, and microfilaments
- mechanical support, maintains shape
- functions in cell mobility
Do cells specialize? how?
yes they do, and it’s by changing the distribution of organelles to become more proficient at certain activities
What are the methods of transport across the cell membrane
Simple diffusion - osmosis
FAcilitated diffusion
active transport
What is simple diffusion
net movement of dissolved particles down their concentration gradient, requires no external source of energy
What is osmosis
simple diffusion of water
What is an isotonic solution
when the internal and external solutions have the same concentration of non-penetrating solutes.
what happens in an isotonic solution
the cell remains normal
what is a hypotonic solution
when the external solution is less concentrated with non penetrating solutes.
What happens in a hypotonic solution
the cell swells up because the water rushes in, it could lead to lyse (when the cell bursts)
What is a hypertonic solution
when the external soultion has a higher concentration of non-penetrating solutes than the cells internal solution
What happens with a hypertonic solution
water leaves the cell causing it to shrivel (this is called plasmolysis)
Do some organisms avoid to osmosis problem
yes, freshwater protozoa have contracting vacuoles that pump out excess water to prevent bursting
What is facilitated diffusion
another type of passive transport, movement of particles down their concentration gradient through special channels or carrier proteins
What is passive vs. active transport
passive requires no external energy, active does
What is active transport
net movement of particles against their concentration gradient with the help of transport proteins. requires either chemical energy (ATP) or an electrochemical gradient
What is circulation
the transportation of material within cells and throughout the body of a multicellular organism
what is brownian movement
the spreading movement of suspended particles throughout the cytoplasm of the cell via the kinetic energy created by collisions
What is cyclosis
also called streaming, its the circular motion of the cytoplasm around the cell transport molecules
how does the endoplasmic reticulum help with intracellular circulation
provides channels throughout the cytoplasm and provides a direct passageway from the plasma membrane to the nuclear membrane
What are the types of intracellular circulation
- brownian movement
- cyclosis
- Streaming
- Endoplasmic Reticulum
What are the types of extracellular circulation
- diffusion
2. circulatory system
What is diffusion
when cells are in direct or close contact with the external environment. can transport food or oxygen.
includes movement from the cells into the interstitial fluid
What is the circulatory system
when cells are too far from the external environment to do diffusion. usually requires vessels to transport fluid and a pump to drive the circulation.
What is the purpose of cell division for unicellular organisms
reproduction
What is the purpose of cell division for multicellular organisms
growth, development, replacement of worn-out cells
What is karyokinesis
nuclear division
what is cytokinesis
cell division
What are the phases of mitosis
- interphase
- prophase
- metaphase
- anaphase
- telophase
- cytokinesis
how much of a cells life is spent in interphase
90%
What happens during interphase
each chromosome is replicated so it can be distributed to both daughter cells upon division
What are sister chromatids
exact copies of each chromosome
where are sister chromatids held together
centromere
what is the DNA like during interphase
uncoiled and invisible (chromatin)
What is a chromosome
- a single chromatid
2. pair of chromatids attached at a centromere
what is a diploid
a cell with a pair of homologous chromosomes
What are haploids
when there is only one half of a pair of chromosomes (gametes)
What is prophase
Initiation of mitosis
- Chromosomes condense
- centriole pairs separate and move to opposite poles
- spindle apparatus forms between centrioles
- nuclear membrane dissolves
- spindles interact with chromosomes
What is metaphase
- Centriole pairs are at opposite poles
- fibers of the spindle apparatus attach to each chromatid at the centromere to align the chromosomes at the center of the cell
- This forms the metaphase plate
What is Anaphase
- Centromeres split so that each chromatid has it’s own centromere. (sister chromatids separate)
- the fibers of the spindle apparatus (microtubules) shorten and pull the sister chromatids to opposite parts of the cell
What is Telophase
- Spindle apparatus dissapears
- Nuclear membrane forms around each set of newly formed chromosomes
- Each nucleus contains the same number of chromosomes as the original parent cell
- The chromosomes uncoil
What is cytokinesis
- Cytoplasm divides into two daughter cells (each with a complete nucleas, and all organelles)
- Cleavage furrow forms and eventually pinches off to form two new daughter cells
what are the two main differences between plant and animal cells during cell division
- Plant cells don’t have centrioles, the spindle apparatus just forms from microtubule organizing centers
- Cytokinesis in plants doesn’t use a cleavage furrow, a cell plate forms (jezz ball)
What is meiosis
the creation of sex cells (gametes)
How does sexual reproduction occur
the synthesis of two gametes
What is the product of mitosis
two diploid daughter cells
What is the product of meiosis
four haploid gametes
What are the phases of meiosis
1. INterphase First Meiotic Division 2. Prophase 1 3. Metaphase 1 4. Anaphase 1 5. Telophase 1 Second Meiotic Division 6. Metaphase 2 7. Anaphase 2 8. Telophase 2
can crossing over occur in mitosis
nope
can crossing over occur in meiosis
yep
What happens in meiosis prophase 1
- Chromatin condenses into chromosomes
- spindle apparatus forms
- nuclear membrane dissapears
- Homologous Chromosomes (one from each parent coding for the same traits) come together and intertwine (Synapsis)
- Chiastima (breaks at overlapping points) can lead to crossing over
what does recombination of chromosomes in prophase 1 do
it leads to increased genetic diversity
What is a tetrad
when two homologous and duplicated chromosomes join together (there are four sets of genes that code for the same traits)
What happens in meiosis metaphase 1
homologous pairs (tetrads) align along the metaphase plate, and each one attaches to a separate spindle fiber by its kinetochore
What happens in ahaphase 1 of meiosis
- Homologous paris separate and are pulled to opposite poles of the cell (Disjuction) Maternal origin DNA and Paternal origin DNA are pulled to separate sides
What is important to remember about anaphase 1 of meiosis
each daughter cell gets a random combination of maternal and paternal DNA in it.
What happens in telophase 1 of meiosis
nuclear membrane forms around each new nucleus, and each cell still has a chromosome of paired sister chromatids joined at the centromere
What happens in the Second Meiotic division of meiosis
basically just mitosis except there is no chromosomal replication first
- chromosomes line up
- half pulled to one side, other half to other
- nuclear membrane forms
- cytokinesis
How many of the 4 haploids produced by meiosis become functional gametes in human females
1
What are the requirements of sexual reproduction
- production of functional sex cells (gametes) by adult organisms
- Union of these cells (fertilization or conjugation) to form a zygote
- Development of the zygote into another adult
What are gonads
organs that produce gametes
What is a hermaphrodite
species that have both male and female reproductive parts
What are two examples of hermaphroditic species
hydra
earthworm
What is spermatogenesis
sperm production
where does spermatogenesis occur
seminiferous tubules of the testes
What is the process of spermatogenesis
- Diploid cells (spermatogonia) undergo Meiosis to make four haploid cells (sperm)
What are the parts of a mature sperm
head
tail
neck
body
What does the head of a sperm consist of
almost entirely the nucleus containing the parental genome
What is another name for the tail of the sperm
flagellum
What does the tail of the sperm do
propels the sperm
What is in the neck and body of the sperm, and what do they do
mitochondria, they provide energy for the cell
What is Oogenesis
the production of female gametes
Where does Oogenesis occur
in the ovaries
what is the process of oogenesis
one diploid primary female sex cell undergoes meiosis and produces a single mature egg (Ovum)
What is a biproduct ofeach meiotic division of the female sex cell
a polar body
What is a polar body
a single cell that contains a little more than the nucleus
What is the Ovum (egg)
A large cell containing most of the cytoplasm, RNA, organelles, nutrients that are needed by a developing embryo
What happens to the polar bodies produced by oogenesis
they rapidly degenerate
What are the differences between oogenesis and spermatogenesis
- sperm - creates 4 haploid cells, oog - creates 1 haploid cell
- Sperm - no polar bodies, oog - polar bodies
- sperm - never ending process, oog - females only have a certain number of eggs
What phase are female eggs frozen in before ovulation
prophase of meiosis 1
When are the meiotic divisions for eggs completed
meiosis 1 is completed at ovulation
meiosis 2 is completed at fertilization
What is fertalization
the union of the egg and the sperm
What is formed from fertilization
a zygote with a diploid number of chromosomes
What are the two types of fertilization
internal and external
when does external fertilization happen
only occurs in vertebrates that reproduce in water.
what happens in external fertilization
females deposit their eggs into the water and males deposit sperm in the vicinity. The sperm then use their tails to swim through the water to the eggs
What happens to chance of fertilization via external fertilization
the chances of fertilization decrease, that is why many many eggs are laid.
When is internal fertilization used
in terrestrial vertebrates
What happens in internal fertilization
the male deposits semen into the female
What happens to the chance of fertilizaiton via internal fertilization
the chances are increased
What happens when you have higher probability of fertilzation
females produce fewer eggs
What else besides an increased probability of fertilization can cause fewer eggs produced in females
early development of offspring occurs outside the mothers body = more eggs are laid to increase chances of survival
More parental after birth = fewer eggs produced
How can you remember the pathway of sperm
SEVEN UP Semeniferous tubules Epididymis Vas deferens Ejaculatory duct (nothing) Urethra Penis
What else do the testis produce
testosterone
What does testosterone do
regulates secondary male characteristics
- facial and pubic hair
- voice changes
What are the parts of the female reproductive system
Ovaries Fallopian tubes Uterus Cervix Vagina
What does the ovary consist of
thousands of follicles
what are follicles
multilayered sacs of cells that contain, nourish, and protect the immature ovum
What prodcues estrogen
the follicle cell
What happens to immature ovum once a month
they are ejected into the oviduct (fallopian tube)
what is the site of sperm deposition
vagina
What are the hormones produced in the ovaries
estrogen and progesterone
What kinds of hormones are the ovarian hormones
steroid hormones
What do estrogens do
- stimulate the development of the female reproductive tract
- contribute to female secondary sex characteristics
- contribute to sex drive
- thicken the endometrium
What do estrogens do to the uterine wall (endometrium)
cause it to thicken
What is the endometrium
uterine wall
What things secrete estrogens
the ovarian follicles and the corpus leteum
When and from where is progesterone secreted
it is secreted by the corpus luteum during the luteal phase of the menstrual cycle
What determines the secretion of estrogen and progesterone
LH and FSH (ant. Pit. Hormones) those are regulated by GnRH
what hormonal secretions play important roles in the menstrual cycle
- ovarian
- hypothalamus
- anterior pituitary
What are the phases of the menstrual cycle
- Follicular Phase
- Ovulation
- Luteal Phase
- Menstruation
What starts the follicular phase
the cessation of the menstrual flow from the previous cycle
What are the levels of reproductive hormones like during the start of the follicular phase
they are at their lowest, which means there is almost no negative feedback to the hypothalamus
What happens when there is no more negative feedback to the hypothalamus during the follicular phase
the hypothalamus can secrete GnRH (gonadotropin-releasing hormone)
What does GnRH do during the follicular phase
it stimulates the release of FSH (follicle stimulating hormone)
What does FSH do during the follicular phase
promotes the development of the follicle in the ovary, which causes it to grow
What happens when the follicle is stimulated by FSH in the follicular phase
the follicle grows and secretes Estrogen
What is ovulation
the bursting of a mature ovarian follicle, which causes the release of the ovum, that is captured by the oviduct.
What causes ovulation
a surge in LH (leiutinizing hormone)
What preceeds and partially causes the peak in LH levels that causes ovulation
an increase in estrogen that is being produced by the mature follicle
When does the luteal phase begin
when the follicle is ruptured by the increase in LH creating the corpus luteum
What does the corpus luteum do
secretes estrogen and progesterone
What does progesterone do in the luteal phase
it causes the glands of the endometrium to mature and produce secretions that prepare the uterus for implantation of the embryo.
How can you remember the pathway of sperm
SEVEN UP Semeniferous tubules Epididymis Vas deferens Ejaculatory duct (nothing) Urethra Penis
What else do the testis produce
testosterone
What does testosterone do
regulates secondary male characteristics
- facial and pubic hair
- voice changes
What are the parts of the female reproductive system
Ovaries Fallopian tubes Uterus Cervix Vagina
What happens in the place of menstruation if the ovum is fertalized
- the developing placenta implants produces hCG (human chorionic gonadotrophin)
- hCG maintains the corpus luteum
- Corpus luteum secretes estrogen and progesterone, which maintains the uterus and endometrium
- Eventually the placenta takes over the production of estrogen and progesterone
what are follicles
multilayered sacs of cells that contain, nourish, and protect the immature ovum
What prodcues estrogen
the follicle cell
What is the gametophyte generation like
- the haploid gametophtye generation produces gametes by mitosis.
- Fertalization by the male and female gametes restores the diploid sporophyte generation
what is the site of sperm deposition
vagina
What are the hormones produced in the ovaries
estrogen and progesterone
What kinds of hormones are the ovarian hormones
steroid hormones
What do estrogens do
- stimulate the development of the female reproductive tract
- contribute to female secondary sex characteristics
- contribute to sex drive
- thicken the endometrium
What do estrogens do to the uterine wall (endometrium)
cause it to thicken
What is the endometrium
uterine wall
What things secrete estrogens
the ovarian follicles and the corpus leteum
When and from where is progesterone secreted
it is secreted by the corpus luteum during the luteal phase of the menstrual cycle
What determines the secretion of estrogen and progesterone
LH and FSH (ant. Pit. Hormones) those are regulated by GnRH
what hormonal secretions play important roles in the menstrual cycle
- ovarian
- hypothalamus
- anterior pituitary
What are the phases of the menstrual cycle
- Follicular Phase
- Ovulation
- Luteal Phase
- Menstruation
What starts the follicular phase
the cessation of the menstrual flow from the previous cycle
What are the levels of reproductive hormones like during the start of the follicular phase
they are at their lowest, which means there is almost no negative feedback to the hypothalamus
What happens when there is no more negative feedback to the hypothalamus during the follicular phase
the hypothalamus can secrete GnRH (gonadotropin-releasing hormone)
what is the anther
a terminal sac of the stamen that produces haploid sportes that develop into pollen grains
What does FSH do during the follicular phase
promotes the development of the follicle in the ovary, which causes it to grow
What happens when the follicle is stimulated by FSH in the follicular phase
the follicle grows and secretes Estrogen
What is ovulation
the bursting of a mature ovarian follicle, which causes the release of the ovum, that is captured by the oviduct.
What causes ovulation
a surge in LH (leiutinizing hormone)
What preceeds and partially causes the peak in LH levels that causes ovulation
an increase in estrogen that is being produced by the mature follicle
When does the luteal phase begin
when the follicle is ruptured by the increase in LH creating the corpus luteum
What does the corpus luteum do
secretes estrogen and progesterone
What does progesterone do in the luteal phase
it causes the glands of the endometrium to mature and produce secretions that prepare the uterus for implantation of the embryo.
Together progesterone and estrogen are essential for the maintenance of the endometrium
uh huh
When causes menstruation occur
- the ovum in not fertilized
- the corpus luteum atrophies
- This causes a drop in estrogen and progesterone levels
- so the endometrium sloughs off
- this gives rise to the menstrual flow (menses)
what is another name for menstrual flow
menses
What happens in the place of menstruation if the ovum is fertalized
- the developing placenta implants produces hCG (human chorionic gonadotrophin)
- hCG maintains the corpus luteum
- Corpus luteum secretes estrogen and progesterone, which maintains the uterus and endometrium
- Eventually the placenta takes over the production of estrogen and progesterone
What is the life cycle of plants like
sporophyte (2n) –> Spore (1n) –> Gametophyte (1n) –> Gametes (1n) –> fertalization –> Sporophyte
What is the female gametophyte in flowering plants
embryo sac
What is the gametophyte generation like
the haploid gametophtye generation produces gametes by mitosis.
How do gametophytes reproduce
sexually (male and female gametes fertalize to produce the sporophtye
How do sporophytes reproduce
asexually
What is an example of a species with the gametophyte as the dominant generation.
Mosses (in this case the sporophyte is a smaller short-lived organism that depends on the gametophyte for energy and nutrients)
What is the sporophyte generation like
- the diploid sporophyte produces a haploid (monoploid) spore my meiosis
- The spore then divides by mitosis to produce the haploid gametophyte generation
What is an example of a species with the sporophyte as the dominant generation
Ferns
What is an angiosperm
a flowering plant that has gametophytes consisting of a few cells that last for a very short time
What is an example of an angiosperm
woody flower plants
What is the reproductive structure of angiosperms
flower
do some species have male and female flowers
yep, some are both in one
what is the male part of the flower
stamen
what is the female part of the flower
pistils
what is fission
a simple form of asexual reproduction seen in prokaryotic organims
what are the parts of the stamen
the filament and the anther
what is the filament
a thin stalk like thing that hold up the anther
what is the anther
a terminal sac of the stamen that produces haploid sportes that develop into pollen grains
What is the pistil
the female organ of the flower that has three parts: stigma, style, and ovary
What are the parts of the pisitl
the stigma, style, and ovary
What is the stigma
the sticky-top part of the pistil that catches the pollen
What is the style
the tube like structure that connects the stigma to the ovary
what is the ovary
the enlarged base of the pistil, it has one or more ovules, and each ovule contains a monoploid egg nucleus.
What are the petals of the flower
they are specialized leaves surrounding and protecting the pistil.
What is the purpose of scents and colors of flowers
they attract insects which transfer pollen between plants to allow for fertalization
What are the sepals
green leaves that cover and protect the flower bud early during development. they may remain after the flower blooms
What are the parts of the flower
stamen
pistil
petals
sepals
What is the male gametophyte in flowering plants
the pollen grain
what makes up the pollen grain
a tube nucleus, and a generative nucleus
what happens when the pollen grain gets to the stigma
the generative nucleus divides to form sperm nuclei
what is the male gamete in flowering plants
sperm nuclei
What does the embryo sac contain
two polar nuclei (endosperms) and an egg nucleus
When does fertalization in flower plants occur
when the sperm nuclei enter the embryo sac.
What happens upon fertalization in flowering plants
one sperm nuclei fuses with the egg nucleus to form the diploid zygote. The other sperm nuclei fuses with the polar bodies (2) to form the endosperm (triploid, 3n)
What does the endosperm do in flowering plants
Provides food for the embryonic plant
what happens to the endosperm in dicotyledonous plants
the endosperm is absorbed by the seed leaves (cotyledons)
What is asexual reproduction
reproduction without fertilization
How does asexual reproduction happen
a single parent cell divides into a new organism
what is special about offspring from asexual reproduction
they are identical to the parent cells genetically. (except for random mutations)
What are the types of asexual reproduction
Fission
Budding
regeneration
parthenogenesis
How do prokaryotes reproduce
asexually
among animals what kinds reproduce asexually
invertebrates
do all plants use asexual reproduction
yep, in some form
what is fission
a simple form of asexual reproduction seen in prokaryotic organims
what kind of reproduction do prokaryotes do
binary fission (asexual)
what happens in fission
- DNA replicates
- New plasma membranes and cell walls grow inward along the midline of the cell
- the cell divides into two equal sized cell with a duplicate of the parent chromosome
for what organisms does fission occur
in single celled organisms amoebae paramecia algae bacteria
What is budding
replication of the nucleus followed by unequal cytokinesis
What are the steps of budding
- Nucleus and DNA replicates
- cell membrane pinches off replicated nucleus forming a smaller but genetically identical cell
- sometimes they stay attached, sometimes they seperate immediately
When does budding occur
in hydra and yeast
What is regeneration
regrowth of a lost or injured body part
How is regeneration done
by mitosis
What are some unique examples of regeneration
a Starfish can lose an arm and regrow it, it can ever regrow it’s body if the arm has a part of the central disk
What does the regeneration of body parts depend on
the extent of nerve damage to the severed body part
What is parthenogensis
the development of an unfertalized egg into an adult organism
What are some example of parthenogenesis
bees and ants (the males develop from unfertalized eggs)
the females and the queen come from fertalized eggs
What are some examples of artificial parthenogenesis
eggs of frogs and rabbits can be stimulated to develop with stimulation or a pinprick
What is alternation of generations
all plants exhibit it, it is when a diploid generation is succeeded by a haploid generation
What is the process of spore formation
the diploid sporophyte generation produces haploid spores that develop into the haploid gametophyte generation
What is the outside of spores like
they have hard coverings that prevent the loss of water
What is vegetative propogation
when undifferentiated tissues in plants provide a source of cells that can develop into an adult plant
What are the tissues in plants that allow them to participate in vegetative propogation
Meristems
What are the two types of vegetative propogation
natural and artificial
What are the advantages of vegetative propogation
- It introduces no genetic variation
2. it is a rapid form of reproduction
What are 4 examples of natural vegetative propogation
Bulbs
Tubers
Runners
Rhizomes
What plants naturally do vegetative propogation by bulbs
tulips and daffodils
the bulbs split to form several bulbs
What plants do natural vegetative propogation by tubers
potatoes
the eye of the potato can develop into adult plants
What are tubers
underground stems with buds (potatoes)
What are runners
stems running above and along the ground extending from the main stem. they can produce new roots and upright stems
What are some examples of plants that do natural vegetative propagation by runners
strawberries and lawn grass
What are Rhizomes (stolons)
woody underground stems that can develop into upright stems
what are some plants that do natural vegetative propagation by rhizomes
ferns and iris plants
What are the two ways that artificial vegetative propagation can be done
- a cut piece of stem can develop new roots in water or moist ground
- (Blackberries and Strawberries) stems that are bent to the ground and covered with soil can take root
What is the process called when you bend down plants (blackberries and strawberries), bury them and they take root
layering
What is the synthetic hormone called that can be used to accelerate root formation
auxins
What is the basic unit of heredity
the gene
What are genes composed of
DNA
where are genes located
on the chromosome
What are the alternative forms of a gene called
alleles
What is someones genetic makeup called
genotype
what is the physical manifestation of their genetic makeup
phenotype
Are all phenotypes the manifestation of one genotype
no, they can be, or they can be the manifestations of multiple genotypes
Who developed the basic principles of genetics by the garden pea
Gregor mendel
How did mendel get to the basic principles of genetics
he crossed pea plants and studied the statistical inheritance of traits
what is mendels first law
the law of segregation
What are mendels four principles of inheritance
- Genes exist is alternative forms (alleles)
- An organism has two alleles (one from each parent) for each inherited trait,
- the two alleles segregate during meiosis resulting in gametes that carry only one allele for each trait
- if two alleles in an organism are different only one will be expressed. Expressed is dominant, recessive is silent
What is a monohybrid cross
when you cross two true breeding plants for a single opposing trait.
What does the F in F generation stand for
filial
What is the result of a monohybrid cross of a PP purple flower and a pp white flower
all plants are heterozygous Pp with a purple flower
What is the ratio when you self cross the F1 generation from the monohybrid cross
1:2:1
PP:Pp:pp
3 purple to 1 white
What is a testcross in genetics
when an organism with an UNKNOWN dominant phenotype is crossed with a true breeding recessive plant.
What are the possible results of the testcrosss (Ax) (aa)
If the unknown dominant phenotype is AA then all of the F1 generation will be purple (Aa)
if the unknown dominant phenotype is Aa then half of the F1 generation will be purple (Aa) and half will be white (aa)
What is mendels second law
independent assortment
What is a dihybrid cross
When you are observing two traits and you cross two heterozygotes for each Trait (AaBb) (AaBb)
What is the law of independent assortment
it means that different traits assort independently, they don’t go to the same gamete consistently
What is a problem in independent assortment
genes on the same chromosome will stay together (violating the law of independent assortment) unless they are exchanged with crossing over
How are the (AaBb)’s obtained that are used in a dihybrid cross
when you cross two true breeding plants for each trait (AABB) (aabb)
What is the results from a dihybrid cross (AaBb) (AaBb)
heterozygous purple tall plants
9:3:3:1 9 purple tall plants 3 purple short plants 3 white tall plants 1 white short plant
What do the ratios 3:1 and 9:3:3:1 from monohybrid and dihybrid crosses tell you
the phenotypic ratio, not the genotypic
What does the ratio 1:2:1 tell you
genotypic ratio.
What are some Non-Mednelian Inheritance patterns
incomplete dominance
Codominance
What is incomplete dominance
when the heterozygous genotype produces a mixture of the two phenotypes.
when the heteozygous phenotype is an intermediate of the two homozygous phenotypes
what is an example of incomplete dominance
snapdragons, when a dominant red is mixed with a recessive white, a PINK flower is formed.
What is codominance
When multiple alleles exist for a gene, and more than one of them is dominant
What happens with codominance
each dominant allele is completely dominant when combined with a recessive allele, but when combined with another dominant allele they are both expressed simultanioulsy
What is an example of codominance
ABO blood groups in humans
How does blood typing work
type A and B and dominant and O is recessive. AB alleles = AB blood OO alleles = O blood AO alleles = A blood BO alleles = B blood AA = A blood BB = B blood
What is an autosome
a Chromosome in sexually differentiated species that doesn’t determine sex
how many autosomes do humans have
22
What are the two types of human chromosomes
autosomes
Sex chromosomes
what causes the 50 percent likely hood of males and females in reproduction
fertilization being an independent event
What are genes called that are located on the sex chromosomes
sex linked genes
What is an example of a y linked genes
hair on the outside of the ears
What happens in males and females when there is an X linked recessive gene
males will always exhibit the trait because they don’t have another allele
females will only exhibit it when both x linked alleles are recessive
(these are far more common in men)
What are some examples of X-linked recessive genes
hemophilia
color-blindness
What are some features of X-linked recessive gene inheritance
- Males only and always pass it to their daughters
- females only exhibit the gene when the father has it and the mother passes it on
- 1/2 of the sons of daughters of a male with the disoder will express it
features of X linked recessive traits
- generally only in males
- they can’t be passed from father to son
- can be passed from grandfather to son via a (mother/daughter) who is a carrier
What is Drosophilia Melanogaster
A Fruit fly
What are the reasons that the fruit fly is such a good study object
- it reproduces often (short life cycle)
- it reproduces in large numbers (large sample size)
- its chromosomes are large and easily recognizable in size and shape
- its chromosomes are few (4 pairs, 2N = 8)
- mutations occur relatively frequently
What is one important thing they have found out by studying Drosophilia melanogaster
how genes expressed early in development can affect the adult organism
What can environmental factors do in genetics
they can often affect the expression of a gene. environmental interaction + genotype = phenotype
what are some examples of environmental factors working with genotype to change phenotype
fruit flies with a given set of genes have crooked wings at low temperatures, but straight wings at high temperatures
The himalayan hare will have white hair on the warmer parts of its body and black hair on the colder parts. if the naturally warm parts are cooled, the hair will grow in black
What are the three types of genetic problems
- Nondisjunction
- Chromosomal breakage
- mutation
What is nondisjunction
either
- failure of homologous chromosomes to seperate properly during meiosis 1
- failure of the sister chromatids to seperate properly during meiosis 2
What are the possible results of nondisjunction
a zygote having 3 copies of a given chromosome (trisomy)
a zygote having 1 copy of that chromosome (monosomy)
What is a case of trisomy
Down Syndrome (trisomy of Chromosome 21)
What happens in the case of most monosomies and trisomies
they are usually lethal and cause the embryo to abort early in pregnancy
Can nondisjunction happen with the sex chromosomes too
yep, this results with people having an extra or missing an X/Y chromosome
What happens when nondisjunction happens at meiosis 1 vs. meiosis 2
meiosis 1
- results in 2 (N +1) and 2 (N-1) gametes
Meiosis 2
- results in 2 normal gametes, 1 (N+1) and 1 (N-1) gametes
What things can cause Chromosomal Breakage
mutagenic agents
X-rays
or it can happen spontaneously
What is said of the chromosome that loses a fragment in chromosomal breakage
it has a deficiency
What are mutations
changes in the genetic information of a cell, coded in the DNA
What can mutations in somatic cells lead to
tumors
What can mutations in sex cells (gametes) lead to
they will be transmitted to the offspring
Where do most mutations in DNA occur
in the regions that do not code for proteins and are silent (not expressed in the phenotype)
What happens with most mutation that do occur in the coding region of DNA and change the AA sequence
most of them are recessive and deleterious
What are things that can cause mutations called, and what are some examples
Mutagenic agents
cosmic rays, X-rays, ultraviolet rays, and radioactivity
chemical compounds like colchicine or mustard gas
what does colchicine do
inhibits spindle formation, causing polyploidy
Are mutagenic agents generally carcinogenic too
yep
What are the three types of gene mutation
addition
deletion
substitution
how do mutations of the genes cause different phenotypes
they can cause the altering of AA sequence which causes changes in the protein
Are mutations permanent changes in the DNA sequence of a gene that alter the AA sequence
nope, they are permanent changes to the DNA sequence of a gene, but they may or may not alter the AA sequence
What is PKU, and what causes it
Phenylketoneuria, a genetic disorder caused by the inability to produce the enzyme for metabolism of the AA phenylalanine.
What does PKU lead to
a loss of the enzyme for Phenylalanine causes it to get degraded to phenylpyruvic acid and its accumulation causes problems
What is sickle-cell anemia
a genetic disorder where red blood cells become crescent shaped because they have defective HGB (it is misshapen and can’t carry as much O2)
What causes sickle-cell anemia
a substitution of valine (GUA or GUG) for glutamic acid (GAA or GAG) in the gene coding for HGB
What is the basis of heredity
DNA
What is the basis for evolution
that changes in DNA are stable and can be passed from generation to generation
What is the basic unit of DNA
the nucleotide
what is a nucleotide made up of
Deoxyribose (sugar) bonded to a phosphate group and a nitrogenous base.
what are the two types of nitrogenous bases
purines and pyrimidines
What are the purines
Adenine and Guanine
What are the pyrimidines
Cytosine, Uracil, and thymine
What are the ways to remember what is a purine and what is a pyrimidine
PUR (purines) As (Adenine) Gold (Guanine)
CUT (cytosine, Uracil, thymine) the PY (pyrimidines)
What pairs with what
T-A
C-G
what does DNA look like
the sugar and phosphate form a backbone with the bases in the middle. two chains are hooked together by bonding between the bases, and the chain coils up making a double stranded helix
how does T bind to A
with 2 hydrogen bonds
how does C bond to G
with 3 hydrogen bonds
What is our understanding of the structure of DNA referred to as
the watson-crick model
What happens to DNA when there is a higher CG content
it will be stronger because of the additional hydrogen bonds are holding the two strands together tighter
What are the steps of DNA replication
- Helicase ang gyrase enzymes unwind the DNA
- RNA primer is added to the 5’ end of the new strand
- DNA polymerase starts adding Nucleotides to both sides simultaneously
In what direction doe DNA polymerase add Nucleotides
5’ - 3’
What are the two strand types called in DNA replication
leading strand and the lagging strand
What does the 5’ - 3’ addition of bases cause
the leading strand is continuously added to, the lagging strand is made in fragments
what are the fragments of the lagging strand of DNA replication called
okazaki fragments
What happnes to the okazaki fragments
They are later joined together by DNA ligase
How is DNA a semiconservative process
Each strand of double stranded DNA acts as a template in the synthesis of 2 daughter strands.
Each new double stranded helix has a new daughter strand bound to a parental strand of DNA.
Two double strand that are identical to the original are formed
What makes up the genetic code
Four letters (ATCG) 20 words (AA's)
What is transcription
DNA code is read to produce an mRNA nucleotide transcript
What is Translation
the mRNA being read to produce proteins
What are codons
a series of triplet codes on mRNA
Is the genetic code universal for all organisms
it’s universal for almost all organisms
What is the degeneracy of the genetic code
that there are 64 different codons, and only 20 Amino acids. so many AA’s have more than one codon specific to them
what is the redundancy of the genetic code
that there are 64 different codons, and only 20 Amino acids. so many AA’s have more than one codon specific to them
so each codon represents only one AA but each AA can be coded for by multiple Codons
yep
What is the start codon
AUG (Met)
What are the stop codons
UAA
UAG
UGA
What is the differences between RNA and DNA
it’s sugar is ribose instead of deoxyribose
it contains uracil instead of thymine
it is usually single stranded instead of double
it can move through the nuclear pores to the cytoplasm
where can RNA be found
both the cytoplasm and inside the nucleus
What are the three types of RNA
mRNA, tRNA, rRNA
What is mRNA
messenger RNA
what does mRNA do
carries the compliment of the DNA sequence and transports it from the nucleus to the ribosome for protein synthesis
is the mRNA strand complimentary to, or the same as the sense strand of DNA
complimentary
what does monocistronic refer to
one mRNA codes for one polypeptide
What types of organisms are monocistronic
eukaryotes
what does polycistronic refer to
one mRNA codes for more than one polypeptide
what types of organisms are polycistronic
prokaryotes
What is tRNA
transfer RNA, small RNA found in the cytoplasm
What does tRNA do
it brings amino acids to the ribosome during protein synthesis.
How many tRNA are there
at least one type of tRNA for amino acid (approximately 40)
what is rRNA
ribosomal RNA, a structural component of ribosomes
what is the most abundent type of RNA
rRNA
Where is rRNA synthesized
in the nucleolus
What are the three parts of transcription
initiation
elongation
termination
What happens in the initiation phase of transcription
- RNA polymerase must recognize the promoter indicating where transcription will begin
- DNA must be unwound by helicase and gyrase
What is the promoter also known as
TATA box
What happens in the elongation phase of transcription
- RNA polymerase add nucleotides to the RNA transcript in the 5’ - 3’ direction
- Transcription factors help with the process
What causes the termination of transcription
when RNA polymerase recognizes a particular sequence on the new transcript.
What is an example of a transcription terminating region
the GC rich hairpin loop in prokaryotes
What is needed to be done for prokaryotic mRNA after transcription before translation
nothing
what is needed to be done for eukaryotic mRNA after transcription and before translation
it is actually called hnRNA right after transcription, and it must undergo post-translational processing
what is post translational processing of hnRNA
- the removing of introns (non-coding sequences)
- the the splicing of exons (coding sequences)
- adding of a 5’ cap
- adding of a poly A tail
Why are 5’caps and poly a tails added to mRNA
in order to protect them from the harsh cytoplasmic environment
Where does translation occur
in the cytoplasm
what are the two binding sites of tRNA and what do they do
AA binding site (recognizes AA)
Codon binding site (recognizes the codon specific to that AA)
What is the codon binding site called
the Anticodon
What is an aminoacyl-tRNA synthase
an enzyme that binds both the AA and it’s corresponding tRNA. forming the aminoacyl-tRNA complex
how specific are the aminoacyl-tRNA synthases
each AA has its own
What are ribosomes
enzymes composed of two units (large and small) that bind together during the initiation of protein synthesis
How many binding sites do ribosomes have and what are they
3
A, P, E
What is the function of the A site on ribosomes
It binds the incoming aminoacyl-tRNA complex
What is the function of the P site on ribosomes
it binds to the tRNA attached to the growing polypeptide chain
What is the function of the E site on ribosomes
it holds the uncharged tRNA as it exits, it is where the mRNA is bound
What does the p stand for in ribosomes binding sites
peptidyl-tRNA binding site
What does the A stand for in ribosome binding sites
aminoacyl-tRNA binding site
What are the three stages of polypeptide synthesis
initiation
elongation
termination
What initiates polypeptide synthesis
- the binding of the ribosome to the mRNA near the 5’ end
- the ribosome scans the mRNA until it binds to the start codon AUG
- the initiator aminoacyl-tRNA complex (methionine-tRNA) base pairs to the start codon
What is the anticodon of the initiator aminoacyl-tRNA complex (methionine-tRNA)
3’-UAC-5’
What happens during elongation of polypeptide synthesis
- hydrogen bonds form between the mRNA codon and the tRNA anticodon in the A site
- a peptide bond forms between the amino acid in the A site and the one in the P site
- the ribosome moves the unchared tRNA to the E site, the one from the A site to the P site, and a new one is brought in
What is the cycle of adding one more AA to the ribosome called
transolcation
what is translocation (ribosomes)
when the ribosome moves three nucleotides in the 5’ to 3’ direction along the mRNA, allowing another AA to enter
What causes the termination of polypeptide synthesis
when one of the three termination codons (UAA, UAG, UGA) reaches the A site of the ribosome
How do the stop codons cause the termination of polypeptide synthesis
they don’t code for amino acids
What is a polyribosome
when there are multiple ribosomes translating the same mRNA strand simultaneously
What is the order of events in polypeptide synthesis
- Small unit binds the mRNA
- when the small unit finds AUG, the met-tRNA binds with its UAC anticodon
- The large unit binds with met-tRNA in the P site
- another tRNA enters the A site
- peptide bond is formed
- tRNA’s shift over
What happens to the protein after it is released by the ribosome
it folds up
can disulfide bonds on proteins be both inter and intra molecular
yep
What is cytoplasmic inheritance
Heredity that comes from the DNA that is found in chloroplasts, mitochondria and other cytoplasmic bodies
can cytoplasmic genes interact with nuclear genes
yep, that is how they help determine characteristics of their organelles
what are cytoplasmic rings of DNA that regulate drug resistance in many organisms
plasmids
how many genes do plasmds contain
one or more
What is the bacterial genome like
a singular circular chromosome located in the nucleoid region of the cell
What is the nucleiod region of a bacteria cell
it’s basically the nucleus without a membrane
Do bacteria also contain plasmids along with their bacterial genome
yep
What are episomes
plasmids that are capable of integration into the bacterial genome
How does bacterial DNA replication go
it starts at a unique origin of replication (ORI) and proceeds in both directions simultaneously.
What direction does DNA synthesis go in bacteria
5’-3’ (just like eukaryotes)
how do bacterial cells reproduce
binary fission and do so very rapidly in good conditions
how do bacteria increase genetic variance of a population since binary fission is asexual
Transformation
conjugation
transduction
What is transformation of bacteria
the process by which a foreign chromosome fragment (plasmid (episomes)) are incorparated into the bacterial chromosome via recombination
What is conjugation of bacteria
sexual mating between bacteria
genetic material is transferred from one bacteria to another temporarily joined to it
how does conjugation in bacteria occur
a cytoplasmic conjugation bridge is formed
genetic material is transferred from the + male to the - female
What must be contained by bacteria if they want to participate in cojugation
Sex factors, without them, no conjugation
What is the sex factor in E.Coli
F factor
what are ecoli cells with the F factor called, and those without it?
F+ cells with it
F- cells without it
What is the exact process of conjugation between ecoli
F+ cells form a conjugation bridge with F- cells
F+ replicates its F factor and gives it to the F- cell
What else can happen with the bacterial chromosome during conjugation
it can begin to replicate and try to move across the conjugation bridge
What happens if the bacterial chromosome doesn’t get all the way across the conjugation bridge before it closes
part of the chromosome goes across into the other cell, there they can recombine with the bacterial genes already there
What are Hfr cells
bacteria with sex factor integrated into the genome that have a High Frequency of Recombination
What is transduction in bacterial cells
when fragments of the bacterial chromosome become packaged into viral progeny made during viral infection
What happens in bacterial transduction
- virus infects a bacterial cell
- virus captures some of the bacterial genome
- virus takes and injects that bacterial genome into a new cell
- that DNA recombines with the new DNA
what affects the probability of recombination between two genes
the more similar they are the more likely they are to transduce
What about transduction allows geneticists to map genes to a high degree of precision
the similarity of genomes dictates the likelyhood of transduction
How do bacteria control their metabolism
by regulating their gene expression
What is bacteria gene expression regulation based on
the access that RNA polymerase has to the genes being transcribed
what is bacterial regulation directed by
the operon
What are the parts of the operon
the operator gene
the promotor gene
What do structural genes od bacteria do
they code for proteins
What is the operator gene
nontranscribable bacterial DNA that is the repressor binding site
What is the promotor gene
noncoding sequence of DNA that serves as the initial binding site for RNA polymerase
what is the regulator gene of BActerial DNA
it codes for the synthesis of the repressor molecule
What does the repressor do
it binds to the operator gene to block RNA polymerase from transcribing the structural gene
What are the two types of regulation for bacterial gene transcription
inducible systems
repressible systems
What are inducible regulation systems
when they need a substance called an inducer for transcription to occur
what are repressible regulation systems
they are in constant state of transcription unless a corepressor is present to inhibit transcription
What happens when RNA polymerase binds to the promoter
structural genes are transcribed
what happnes when the repressor binds the operator
RNA polymerase is blocked = notranscription
What happens when the inducer binds to the repressor
no binding to operator = transcription
how does the inducer casuse transcription to occur in inducible systems
the inducer binds to the repressor, making it so it can’t bind the operator
What kind of systems often use the inducible regulation systems
enzymes (the inducer is a substrate of the enzyme) so when the substrate is present the enzyme is made, when it is absent no enzyme is made
what are the four parts of DNA that affect the transcription
- Regulator (makes repressor)
- Promoter (binds RNA polymerase to begin)
- operator (binds repressor to stop transcription)
- Structural (codes for proteins)
what happens in a repressible regulation system of bacterial transcription
the repressor is inactive until it binds the corepressor, once it has formed the repressor/corepressor complex it can bind the operator and block transcription
what kinds of things often make corepressors for repressible systems
the end products of the biosynthetic pathways they control
what is a constitutive operon
when an operon has mutations that don’t allow repressors to bind and thus are always synthesizing enzymes
What is a bacteriophage
a virus that infects its host bacterium by attaching to it, boring a hole through the bacterial cell wall, and injecting its DNA.
What happens to the protein coat of the bacteriophage after it’s DNA is injected into the bacterial cell
it is left attached to the cell wall
What happens when the bacteriophage has entered the cell
it begins its lytic cycle or its lysogenic cycle
What is the lytic cycle
When the bacteriophage DNA takes control of the bacteria’s genetic machinery and manufactors numerous progeny. then the bacterial cell bursts and realeses new virions. (a process of virus replicaiton)
What are bacteriophages that replicate via the lytic cycle called
virulent
what happens if the infection of a virulent bacteriophage takes place on a bacterial lawn (plated culture)
a plaque or clearing in the lawn will occur where the lysed bacteria used to be.
What is the lysogenic cycle
the bacteriophage doesn’t lyse it’s host cell and becomes integrated into the bacterial genome in a harmless form (prophage) for one or more generations
What can happen once the bacteriophage has entered in the lysogenic cycle
it can remain dormant, replicating with the bacterial genome, or it can re-emerge and enter the lytic cycle
What can cause the re-emergence of the bacteriophage from the lysogenic cycle to the lytic cycle
can happen spontaneously or by
radiation, UV light, chemicals
what is a possible benefit of bacteria containing prophages
they can’t be further infected (superinfection) by similar phages
What is gel electrophoresis for
separate molecules of different sizes using a charge gradient
What is an agarose gel for
seperating DNA molecules on different sequence lengths
what is a polyacrylamide used for
to separate proteins of various amino acid lengths
When is blotting used
it is used to detect molecules and preserve the sample for future use
what is southern blotting
it allows for the detection of a specific sequence in a sample of DNA.
how is southern blotting done
the DNA is cleaved into small fragments by restriction endonucleases
the fragements are then seperated using gel electropresis
the seperated fragments are then moved to an inert membrane using blotting techniques
the desired sequence is located by exposing the blot to a radioactively labeled probe.
What is northern blotting
blotting used for the detection of RNA
what is western blotting for
blotting used for the detection of proteins
How is DNA amplification done
by PCR polymerase chain reaction
What are the three steps of PCR
- denaturation
- primer annealing
- primer extensions
How is DNA denatured in PCR
HEAT, which separates the strands so you can get the desired sequence
What happens in the annealing step of PCR
complimentary nucleotides called primers attach to the single stranded templates, then DNA polymerase EXTENDS THE PRIMER by attaching the rest of the complimentray bases
What is a second way to amplify genes (besides PCR )
cloning
how is DNA cloning done
The DNA sequence of interest is joined to vectors (self replicating phages or plasmids) via DNA ligase
Then that is inserted into a bacterial strain through transformation.
Then the bacteria will produce copies of the DNA using its own natural processes
What is the most popular way to sequence DNA
chain termination method
how does chain termination method of DNA sequencing work
it uses dideoxynucleotides (ddNTP’s) in replication reactions and then separates the resulting single-stranded DNA molecules by gel electrophoresis
What do dideoxynucleotides do (ddNTP’s)
they are nucleotides that have been modified to prevent the addition of more nucleotides
WHat is used to analyze DNA for the presence of disease genes
Restriction fragment length polymorphisms (RFLP’s)
What is RFLP
restriction enzymes bind to and cut the double stranded DAN at specific sequences.
How do you know if an RFLP has shown you that there is a disease in the DNA
if there is a variation in the fragment length when there is a difference in that specific sequence.
What do you need to know well for an RFLP to help you identify disease
you need to know the restriction enzyme habits, and the size of fragments they should make for that gene
