Topic 6 cont'd - smtaylor

triteritzyBiotechnology

Dec 14, 2012 (4 years and 8 months ago)

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The Living Environment

Regents Review

Topic 1: Similarities & Differences
Among Living Organisms

Organelle

Function

Human System

Nucleus

Control center

Nervous & endocrine

Mitochondria

Aerobic respiration

Circulatory, digestive,
respiratory

Ribosome

Protein synthesis

Digestive, circulatory

Cytoplasm

Holds organelles,
transport

Circulatory

Vacuole

Storage of wastes

Excretory

Lysosome

Intracellular digestion

Digestive, immune

Cell membrane

Regulates passage of
substances in and out of
cell

Immune system

Topic 1 cont’d


Transport


Cell membrane is a lipid bilayer (two layers of lipids with proteins in
between
-

some acting as channels and receptors)


Concentration gradient (when a difference in the amount of a particular
substance exists across a barrier such as the cell membrane)


Passive transport (diffusion)
-

substances move along concentration
gradient (from high concentration to low) WITHOUT the use of energy


Ie. O
2,
, CO
2

& H
2
O (osmosis)


Saline solution (water moves out of cells


dehydrate)


Distilled water (water moves into the cells


swell & potentially
burst)


Active transport
-

substances move against concentration gradient
WITH the use of energy in the form of ATP


Na+ and K+ are kept at high levels in and out of the cell to
maintain a gradient for nerve impulses (sodium/potassium pump)

Osmosis

Red onion cells in
concentrated salt
solution (osmosis
out of cell)

Red onion cells in distilled
(100% water) (osmosis into
the cell)

Topic 1 cont’d


Cell receptors


Extend off of cell membrane


Have a specific shape


Only recognize certain substances to
allow in or out of the cell


Neurons (nerve cells) have receptors
for specific chemicals
(neurotransmitters)


Certain cells have receptors for
certain hormones as the hormones
travel throughout the circulatory
system to reach target cells


Antibodies


Proteins produced by B cells in
immune system (white blood cells)


Specific in shape for particular
pathogens


They isolate pathogens for
destruction by other white blood cells

Topic 2: Homeostasis in Organisms

Process

Location

Raw
materials

Products

Role in
homeostasis

Photosynthesis

chloroplast

CO
2

& H
2
O

Glucose,

O
2
, & H
2
0

Provides
food (simple
sugars) for
producers

Respiration

mitochondria

Glucose &
O
2

(aerobic)

ATP, CO
2
& H
2
O

Releases energy
from chemical
bonds of
glucose to the
usuable form of
ATP

Topic 2 cont’d


Enzymes:


Proteins


Specific shape so that they
only fit with a certain
substrate


Enable (allow) reactions to
occur faster and with less
energy (organic catalysts)


Have optimal pH and
temperature (if outside of
optimal range the enzyme can
be denatured (change shape)
and be unable to function
properly

Topic 2 cont’d


Feedback mechanisms


Most common type in the human body is negative feedback


Something is off unless activated, once its job is completed
it is deactivated


Comparable to a thermostat (it only signals the oil burner to
turn on when the temperature drops below predetermined
level
-

once temp. is restored a signal is sent to turn off the
oil burner)


Our hormones typically work in this fashion


Insulin is produced by the pancreas in response to an increase in
blood sugar levels


the sugar is taken in by the liver and converted to the
polysaccharide glycogen


once levels are low enough a signal is sent to the liver to stop
insulin production

Topic 2 cont’d


Guard cells and feedback:


Guard cells are
specialized cells found
mainly in the lower
epidermis of a leaf


They regulate an opening
called a stomate, which
allows gases such as CO
2
,
H
2
O & O
2

in and out as
needed by the plant


The guard cells keep the
stomate closed unless the
plant needs gases to enter
or leave

Guard cells w/
open stomate
(top view)

Cross section of leaf
epidermis w/ guard
cells & stomate

Topic 3: Genetic Continuity


DNA= deoxyribonucleic acid


Nucleic acid


Double helix


Building blocks = nucleotides


Sugar (deoxyribose)


Phosphate


Nitrogen base (A,T,C,G)


A
-
T & C
-
G


RNA = ribonucleic acid


Nucleic acid


Single stranded


Building blocks = nucleotides


Sugar (ribose)


Phosphate


Nitrogen base (A,U,C,G)

Topic 3 cont’d


DNA replication


Unwinds


Unzips between bases


Two identical molecules are created


Occurs prior to mitosis


Protein synthesis


DNA has instructions for a particular protein


The portion needed unwinds and unzips


mRNA is created from the DNA template to carry code from nucleus to
ribosome (transcription)


At the ribosome the mRNA is read in groups of three bases (codons)


tRNA delivers the appropriate amino acids over to the codons on
mRNA and then leaves


Peptide bonds join the amino acids together to create a polypeptide
(protein)

Topic 3 cont’d


Genetic engineering:


Gene splicing
-

restriction enzymes used to cut out
desired gene from DNA


Desired gene from one organism is inserted into the
DNA of another organism


The gene for human insulin has been successfully
inserted into a plasmid (circular portion of DNA) of
bacteria


bacteria produce human insulin and pass this
trait onto their offspring


Genes for herbicide resistance, frost resistance, nutrient
content etc. have been inserted into plant DNA (crops
such as corn, rice, tomatoes)

Chromatography Gel Electrophoresis

Topic 3 cont’d


Selective breeding:


Farmers have been doing this for
years


Select seeds from desirable
plants (biggest corn, juicy
tomato etc.) and only grow the
seeds from those plants


This is also done with livestock,
racehorses and dogs


Certain individuals are
chosen to mate so that their
desirable traits are passed on
to offspring


Decreases biodiversity


Recessive traits (such as
diseases) can become more
prominent

Topic 4: Reproduction &
Development


Meiosis


cuts chromosome number in half in the
creation of gametes (egg and sperm
-

contain
monoploid/haploid (n) amount of chromosomes)


Crossing over and genetic shuffling increase variety
in gametes


Meiosis occurs in the gonads or sex organs (ovaries
& testes)


Fertilization is the union of egg and sperm to restore
diploid number (2n) of chromosomes to create a
zygote


Cleavage or mitosis in a zygote increases the number
of identical cells


Stages of cleavage

Topic 4 cont’d


Differentiation is the process by which cells are given specific
instructions through the activation of certain portions of their
genetic code


Fertilization occurs in the fallopian tube of a human female
(oviduct)


The zygote implants in the uterus and a placenta develops
from the uterine wall for the transport of nutrients and wastes
between mother and fetus


Feedback is involved in regulating the menstrual cycle
involving the pituitary gland in the brain, the ovary and the
uterus

Topic 4 cont’d


Reproductive technology:


IVF
-

egg and sperm are harvested from parents and united
in a petri dish


Cloning
-

a nucleus from a body cell of the organism to be
cloned is put into an empty egg


The egg with the transplanted nucleus is treated with growth factors


When the zygote has divided (morula stage) it is put in a surrogate
for gestation


Screening:


Amniocentesis
-

amniotic fluid is sampled to screen for genetic
disorders


Karyotype
-

chromosomes in amniotic fluid are harvested and
arranged in order from # 1


23 to screen for chromosomal
disorders such as Down Syndrome


Ultrasound

Normal Karyotype

Karyotype of Individual withDown
Syndrome

Topic 4 cont’d


Mitosis: involved in asexual reproduction


IPMAT:


Interphase
-

majority of the lifespan of a cell (all life
functions and chromosomes replicate)


Prophase
-

chromosomes become visible and nuclear
membrane begins to break down


Metaphase
-

double
-
stranded chromosomes line up at the
middle


Anaphase
-

chromatids separate toward poles of the cell


Telophase
-

nuclear membrane reappears around each set
of chromosomes and the cell membrane begins to pinch
in (or in a plant cell a cell plate forms from the inside
out)

Topic 4 cont’d


Types of asexual reproduction:


Binary fission (equal cytoplasmic division)
-

bacteria


Budding (unequal cytoplasmic division)


yeast
(unicellular) and hydra (multicellular)


Vegetative propagation


part of a plant is used to grow an
exact copy of that plant (leaves, stems etc.)


Regeneration


a part of the organism can be replaced or an
entire organism can be created from that piece (starfish,
lizard tail)


Budding in yeast

Unicellular Bud

Multicellular
bud

Budding in hydra

Topic 5: Evolution


Natural selection (Charles Darwin)


Overproduction = more offspring produced than can
possibly survive


Competition (struggle for survival)
-

there are limited
resources


Variation
-

some will have a particular trait or set of traits
that are favorable while others will not


Survival of the fittest
-

those with the favorable trait will be
more likely to survive reproduce and pass the trait on to
their offspring


** Over time the population SHIFTS to CONSIST of
mostly those with the favorable trait (
DO NOT

SAY
BECOME RESISTENT ETC.!!!!!!!)**

Topic 5 cont’d


Evidence of evolution:


Homologous structures



similar in origin and layout but
may be different in function
and appearance (suggest a
common ancestor)


Comparative embryology
,
cytology and biochemistry are
all types of molecular evidence
based on DNA and are
therefore more reliable than
physical evidence

Topic 5 cont’d


Adaptations = favorable traits for a particular
environment at a particular time that increase chances
of survival


Selecting agents (an environmental factor such as
food source that determines which traits in a
population are favorable)


Speciation


creation of a new species as the result of
accumulating enough different adaptations from the
main population to be able to successfully reproduce
fertile offspring


Reproductive and geographical isolation contribute to this


Adaptive radiation


development of several new species
from a single common ancestor (finches)

Variation in shell
coloration/pattern

Overproduction of
clownfish eggs

Topic 6: Ecology


Levels of organization:


Biosphere


biomes

ecosystem

community

population (greatest
biodiversity to least amount of biodiversity)


Abiotic = all nonliving factors in an ecosystem (ie. Carbon
dioxide, water, sunlight, temperature, pH)


Biotic= all living factors in an ecosystem (algae, trees, frogs,
minnows, foxes, sharks etc.)


Food webs provide illustrations of all possible pathways of
energy/nutritional relationships in an ecosystem (more stable)


Food chains indicate one pathway of energy/nutritional
relationships in an ecosystem


Topic 6 cont’d


Producers are always found at the base in an
ecosystem/foodweb/foodchain/food pyramid because
they contain the most available energy


Energy CANNOT be recycled in an ecosystem and
must be constantly SUPPLIED for it to remain stable


Materials such as carbon dioxide, water, oxygen,
nitrogen must be RECYCLED by decomposers such
as bacteria and fungi for an ecosystem to remain
stable

Topic 6 cont’d


Nutritional Relationships/trophic levels


Producers/autotrophs convert light energy into chemical
energy in organic compounds (glucose)
-

a.k.a
-

make their
own food (inorganic raw materials


organic product)


Primary consumers (herbivores)
-

consume only producers


Secondary consumers (can be omnivores or carnivores)
-

consumer other consumers and sometimes some producers


Teriary consumers (typically carnivores) consume
primarily other consumers


Scavengers consume dead organisms (turkey vultures,
hyenas, raccoons)


Decomposers break the remains of dead organisms (and
their wastes) down to recycle their nutrients back into the
ecosystem

Topic 6 cont’d


Symbiotic relationships:


Mutualism (both benefit: +,+) (ie. Remora
cleaning parasites off of a shark)


Parasitism (one harmed, one benefits:
-
,+) (ie.
Ticks and dogs, tapeworm and human)


Commensalism (one benefits, one unaffected: +,0)

(best example is barnacles on a whale)

**Predator/prey is NOT a symbiotic relationship
because it is short term
-

once the prey is caught the
relationship is over


Barnacles on a whale

A remora and a shark

Tick on a dog

Topic 6 cont’d


A habitat is where an organism lives and its niche is its role in that habitat
(ie. What it consumes)


Competition results over limited resources as there can only be one species
per niche in an ecosystem


Limiting factors help keep populations in an ecosystem in check: ie.
Predators keep their prey populations in check and visa versa, light
intensity controls where plants can grow, temperature, pH (they can be
biotic or abiotic)


Carrying capacity = the amount of a particular population that can be
maintained indefinitely in an ecosystem (determined by limiting factors)


Ecological succession (due to natural disaster such as a volcanic eruption or
forest fire)


Pioneer organisms are the first to show up and can survive harsh conditions (ie.
Lichens, grasses, mosses)


Climax community is the final, stable, self
-
sustaining stage that can last until a
major disruption


Each stage paves the way for the next, making them self
-
sacrificing

Carrying Capacity Graphs

Topic 7: Human Impact


Global Warming


Cause
-

excess greenhouse gases in atmosphere trap heat


Carbon dioxide is the most common greenhouse gas
released


Burning fossil fuels and deforestation are two major
sources of increased atmospheric carbon dioxide


Cleaner fuel sources such as solar power, wind etc. are
ways to reduce greenhouse gas emissions


Reforestation is another way as trees take in CO
2

from the
atmosphere for photosynthesis


Burning fossil fuels also releases sulfur dioxide which can
cause acid rain!

Topic 7 cont’d


Ozone depletion:


Cause is CFCs from coolants in refrigerators, ACs, and in
aerosols


Montreal Protocol banned CFCs however older appliances
if disposed of improperly can release CFCs into the
environment


Not all countries adhere to this ban, thus some CFCs are
still used in products globally


The ozone protects organisms from more harmful UV rays
getting through, but the thinner it is the more rays can
enter,
increasing

the incidence of
skin cancer


Laws must be enforced globally banning CFCs and there
must be stricter penalties for improper disposal

Topic 7 cont’d


Biological Controls:


Pesticides can harm species other than those that are being
targeted


Biological controls are natural remedies for pest control
and include natural predators of pest species and sterilizing
individuals to prevent reproduction


Advantages = target pest populations only, can be cheaper


Disadvantages= the natural predators may begin to
consume native species or compete for a niche with a
native species


Biomagnification = greater quantities of pollutants are
found in top level consumers as each successive level
consumes more of the previous level (ie. DDT still found in
fatty tissue of humans)


Topic 7 cont’d


Deforestation


Leads to loss of habitat


Decreases biodiversity


Medicines and other medical advancements may
go undiscovered


Increases carbon dioxide in atmosphere as there
are less trees to take it in for photosynthesis


Stricter laws should be passed to limit and
reforestation can reverse the effects as long as it is
done at a rate to compensate

Topics 8&9:

Lab Skills and Scientific Method


Scientific Method
-


Problem: Phrased as a question


Ie
. How does pH affect petal color?


Hypothesis: Phrased as a statement


Ie
. It is hypothesized that an acidic pH will produce flowers with
red petals, while a basic pH will produce flowers with white petals


Design a controlled experiment:


Only one variable (
ie
. pH level) = INDEPENDENT


DEPENDENT VARIABLE relies on independent
ie
. Growth relies
on or depends on the pH, temperature, amount of sunlight etc.


Other factors remain the same (constants) (
ie
. Plant species, amount
of water, sunlight, temperature)


Collect measurable data (
ie
. Number of plants with red petals and
number of plants with white petals in each group)


Topics 8&9 cont’d


Organize data into a table with headings and units and create an
appropriate graph with an even scale and labels


Large sample size (the more specimens in each group the more
reliable the data
-

accounts for variety)


Draw a conclusion (state whether or not the hypothesis was
supported and provide data from the experiment to support)
(ie. Out of 50 plants in the acidic pH 45 of them had red
petals, while in the basic pH 49 of the 50 plants had white
petals, therefore the hypothesis that flowers grown in acidic
soil will have red petals was supported)


Future research


explain how the experiment could be
improved in the future or expanded upon


Topics 8&9 cont’d


1cm = 10 mm


1mm = 1000
µm


Microscope:


Coarse adjustment (only under low power)


Fine adjustment (for both)


Eyepiece (ocular) typically 10x


Objectives (low typically 10x, high typically 40x)


Total magnification = eyepiece x objective


Images appear upside down and backwards and appear to
move in opposite direction


High power has a SMALLER field of view and is
DARKER than low power!!

Topics 8&9 cont’d


Chromatography
-

separates pigments into color
components (those that are more water soluble travel
further up the paper)


Gel electrophoresis
-

restriction enzymes cut DNA
from each individual into fragments of various sizes


The DNA of each individual is loaded into a separate well
in the gel


The gel is hooked up to a current (negative at the top and
positive at the bottom) as DNA has a negative charge it is
drawn toward the bottom toward the positive charge


A banding pattern is created as the larger fragments settle
toward the top and the smaller ones toward the bottom


Both techniques are used to determine
evolutionary relationships (common ancestry)



Topics 8&9 cont’d


Indicators:


Starch indicator (Lugol’s iodine)
-

goes from an amber/gold
color to a deep blue/purple in presence of starch






Glucose indicator (Benedict’s solution)
-

goes from a pale
blue to an orange/green color in the presence of glucose
WHEN HEATED!