Bio 4A exam 1

Biology is

The study of life

There are four important biological molecules

Lipids, protein, carbohydrates, and nucleic acid. These four make up all living organisms

Describe the biological hierarchy of organization from smallest to largest

It goes from atom to molecule to cell to tissue to organ to organ system to organism to population to community to ecosystem and lastly biosphere

Atom

Smallest unit of an element

Molecule

When two atoms are chemically bonded or more atoms

Cell

Basic unit of life

Tissue and it’s four major categories

Group of similar cells with common structure and function working together. The four major categories are nervous, muscle, connective, and epithelial

Organ

Multiple tissues working together at a common task. Tissues are connected together to form an organ

Organ system

Multiple organs working together

Organism

An individual living thing

Population

Individuals that interact and integrate with each other. They can grow and shrink. Think of a population of humans for example, it’s just humans

Community

Involves all living organism, the biotic factors. Plants, animals, humans

Communities are found in unique locations known as

Ecosystems which contain all non living things (abiotic factors) like temperature

We reside in a particular ecosystem because we have certain adaptations and all different ecosystems make a

Biosphere

What is the lowest level of organization that possesses all attributes of life

Cells, they are the smallest level that can independently carry out the characteristics of life

All cellular life is divided into three domains

Bacteria, archaea, and eukarya

Examples and characteristics of bacteria

E.coli, Cyanobacteria are some examples

They are prokaryotic, have no nucleus, and usually unicellular

Examples and characteristics of archaea

Methanogens, halophiles, and thermophiles are examples

They are prokaryotic, no nucleus, and often live in extreme environments

Eukarya examples and characteristics

Animals, plants, fungi, protists

They are eukaryotic, have a nucleus, and have membrane bound organelles

Where would you find archaea and what do they do

Since I said found in extreme environments some examples could be very hot places, very salty environments like salt lakes, very acidic environments, and oxygen free environments

They are often called extremophiles because they can survive conditions that would kill most organisms

It’s not that they can only live in extreme environments, they can also live in ordinary environments such as soil and oceans

They drive global nutrient cycles like nitrogen and carbon, they produce methane and more

What does it mean to form domain of life

A domain of life is the highest most broad rank used to classify all living organisms on earth

What are the 7 attributes of life

Order, reproduction, growth and development, energy processing, response to environment, regulation/ homeostasis, and evolutionary adaptation

Order

Living organisms have a highly organized structure because life isn’t random, and biological structures are organized in ways that allow them to function

Reproduction

Organisms produce new organisms. There are two major types, asexual and sexual. Reproduction allows life to continue across generations

Sexual vs asexual reproduction

Sexual reproduction is meiosis while asexual reproduction is mitosis

Asexual is one parent to offspring or single celled producing two genetically identical daughter cells

Mitosis or asexual reproduction is exact copies of cells and producing genetically identical offspring

Common example of mitosis is growth, repair, and replacement of cells

Meiosis or sexual reproduction involves genetic material from two parents . It produces four genetically unique gametes or sex cells. Passing down genetic info means undergoing meiosis

Produces genetically different offspring and it’s important to evolution because it increases genetic variation which gives natural selection more variation to act upon

Growth and development

Organisms increase in size and undergo change during their life. It’s important because cells divide, grow, specialize and change according to genetic instructions

Energy processing

Living organisms acquire and use energy. Plants use photosynthesis and human cellular respiration.

Ultimate source of energy for planet is sunlight, it comes down to earth which humans can’t use directly but plants capture light and convert it to usable chemical energy and we eat plants or animals that have eaten plants

What is metabolism, and catabolism vs anabolism

Metabolism is all the chemical reactions we have in our body, there are two types of metabolic reactions

Anabolism build larger molecules from smaller molecules and usually requires energy. A common example is growth, repair, and replacement of cells. You can also think amino acids to protein

Catabolism is the breakdown of larger molecules into smaller molecules, it often releases energy. Common example Is digestion or protein to Amino acids

Response to the environment

Organisms detect and respond to changes in their environment

Like when you touch something hot and pull your hand away

Responding to the environmental changes increase an organisms ability to survive

Regulation/ homeostasis

Homeostasis is organisms maintaining a constant internal environment despite environmental changes

Like your body maintaining a relatively stable temperature

It’s important because cells function best within certain ranges of temperature, pH, water balance and more

How maintaining homeostasis works

A stimulus occurs which is any detectable change in an organisms internal or external environment that disrupts the body’s stable state. Sensors then send data to your control center, like your CO2 levels. Our control center gives a direct response to the stimulus and there’s an effect. Either negative or positive feedback and return to normal

Positive vs negative feedback

Negative feedback is when the response counteracts the original change

It helps maintain homeostasis

An example is body temp. Our body temp rises. Our brain detects the increased temperature. Sweating increases. Heat is lost. Temperature decreases towards normal

Change to response to reverse change

Positive feedback amplifies the original change

During childbirth the baby pushes against crevice, a hormone called oxytocin is released, there are now stronger contractions, more pressure on the cervix, more oxytocin is released, now even stronger contractions until baby comes out

Change then response then increased change

Positive feedback doesn’t mean good and negative feedback bad

how are proteins made

The chain goes from DNA to RNA to protein known as central dogma

Step 1 is transcription which is DNA to mRNA. A gene in DNA is copied into messenger RNA which occurs in the nucleus of eukaryotic cells

Step 2 is translation which is mRNA to protein. The ribosome reads the mRNA and uses that information to assemble amino acids into proteins. This occurs at the ribosome

Our genetic code is very universal if your take a gene out of one organism and stick it into another it should be able to make that gene

What is the seventh characteristics of life

It is evolutionary adaptations which means a population changes over generations as organisms with advantageous heritable traits become more common.

Example is bacteria becoming resistant to antiobiotics

Evolution explains how populations become better suited to their environment over generations

Evolution

The genetic makeup of population changing over time

It is the population that evolves not individual organisms

Natural selection

Occurs when individuals with certain heritable traits survive and reproduce more successfully than others

If a population of insects has brown and green insects, and birds can easily see the green insects but have difficulty seeing the brown ones the brown insects will survive and reproduce more often and over generations brown coloration becomes more common

Genotype vs phenotype

Genotype is the organisms genetic makeup like BB, Bb, or bb

Phenotype is the organisms observable characteristics like brown eyes and height

Think DNA TO RNA TO PROTEIN TO TRAITS

your dna contains genes and genes are expressed through RNA and proteins which proteins contribute to traits THEREFORE GENOTYPE + ENVIRONMENT = PHENOTYPES

PHENOTYPE ISNT ALWAYS DETERMINED BY GENOTYPE ALONE AND ENVIRONMENTAL FACTORS CAN AFFECT PHENOTYPE

What determines which members in the population have better phenotypes

Environment

what is central dogma and define each part

DNA to rna to protein to phenotype

DNA stores genetic info

RNA carries and uses the genetic info

Protein performs many functions and contributes to traits

Phenotypes are observable characteristics

What is differential reproduction

Some individuals leave more offsprings than others as they have certain traits that may have greater reproductive success

Evolutionary fitness refers to reproductive success not simply strength, size, or intelligence

What is selective pressure

Any environmental factor that alters the behavior and fitness of living organisms. It acts as a filter as organisms with advantageous traits survive the pressure and pass those winning genes to their offspring while others die or fail to reproduce

Selective pressure acts on phenotype

Natural vs artificial selection

Natural selection is when the environment determines which traits result in greater reproductive success

Artificial selection is when humans determine which organisms reproduce based on desired traits

What are adaptations

Specific physical or behavioral traits that help a living thing survive in its environment

Variations in a population could be the result of a…

Mutation. They are changes in the genetics of an individual that could be good, bad, or have no change

Bacteria have —- in their small circular pieces of DNA called —- that allows them to be more —-

Genes, plasmids, resistant

There are 5 important points to know about the cellular basis of life

1) all organisms are composed of one or more cells

2) the cell is the basic unit of life

3) all cells come from preexisting cells

4) cells contain hereditary information known as DNA

5) cells carry out the basic processes necessary for life

What is the cell theory

1) all living organisms are made of cells

2) the cell is the basic unit of life

3) all cells come from preexisting cells

How are cells categorized

They are divided into prokaryotic and eukaryotic

Prokaryotic are like bacteria and archaea:

They have no nucleus, DNA is not enclosed in a nucleus, no membrane bound organelles , smaller and simpler

Eukaryotic cells are Animals, plants, fungi, and protists:

They have a nucleus, have membrane bound organelles, generally larger and more complex

How do humans fit in the natural world

Humans are part of nature not separate from it.

We are organisms, eukaryotes, animals, and mammals

We depend on the ecosystem for food, water, oxygen, and energy

We also affect the ecosystem through agriculture, pollution, deforestation, climate change and more

Does science have social responsibilities

Yes, science is a way of acquiring knowledge about the natural world. It has a responsibility to make sure the info we’re acquiring can be spread down to others

Scientists have a responsibility to consider how scientific knowledge and technologies affect human health, society, environment, and future generations

While science provides evidence, scientists and society must consider the ethical consequences like medical research and pollution

How have humans influenced the ecosystem

Positively we have restored damaged habitats, conserved water, used renewable resources, reduced pollution, replanted forests, and protected endangered species

Negatively we overhunt, cause pollution, destroy habitats, cause deforestation, reduce biodiversity

We modify the ecosystem for our own purposes and as we modify it we create a lot of destruction by decreasing biodiversity

What is biodiversity

It is the variety of life, number of different organisms living in a specific area.

As we try to expand biodiversity we end up with habitat loss causing climate change which causes extinction

Changes in human behavior and use of new technologies can result in new diseases

Biodiversity can be considered at several levels like genetic diversity is the variation in genes within a species. Or species diversity is variety of species in an ecosystem

Scientific method

1) make an observation 2) ask a question 3) form hypothesis that answers the question 4) make predictions based on hypothesis 5) design an experiment to test the prediction 6) analyze the results 7) hypothesis is correct or incorrect 8) report results

Science is —— it’s nots simply question to experiment to done. Results can lead to new questions and hypotheses

Iterative

What is a hypothesis?

Hypothesis is an educated guess and it makes it educated because you have background research on it. Your hypothesis is a tentative explanation that is testable for your observation. It is falsifiable. Tentative means something that is not fully worked out

No versus alternative hypothesis

Alternative hypothesis also known as Ha is when there is an effect or difference and relationship

Example is when plants are exposed to more light they will grow taller than plants exposed to less light

Null hypothesis is when there’s no effect or differenceThe symbol is Ho

Example is when there’s no difference in plant growth between the two light conditions

In science, you never prove a hypothesis —- you either support it or fail to support it

True

What is deductive reasoning?

Deductive reasoning often follows if to then

You start with a hypothesis and make a specific prediction

For example, your hypothesis is light increases plant growth. Then your prediction is IF light increases plant growth THEN plants exposed to more light to grow taller than plants exposed to less light.

HYPOTHESIS IS AN EXPLANATION WHERE PREDICTION IS AN EXPECTED RESULTS

Qualitative versus quantitative

Qualitative is descriptive and non-numerical so color or height

Quantitative is numerical like a plant is 15 cm tall or 72 cell were counted

How do scientists develop hypothesis?

They develop hypothesis based on observations, existing knowledge, previous research, patterns, and data and scientific literature. Then they create a hypothesis that can be tested and potentially falsified.

Predictions tells scientist what should —- if their hypothesis is —- it gives you something specific to test. For example if the hypothesis is that fertilizer increases plant growth then the prediction is plants receiving fertilizer will have a greater average height after four weeks then plants not receiving fertilizer. The —- allows you to compare the actual results to the expected results.

Happen, correct, prediction

Why are controls used?

A control provides a baseline for comparison

It helps to determine whether the experimental treatment caused the observed effect

For example, if you wanna know whether a drug lowers blood pressure, you could have an experimental group with the drug and a control group with no drug so if blood pressure decreases significantly more in the drug group, you have evidence that the drug may have caused the effect

Without a control, you may not know whether the change was caused by your treatment, natural variation, time,environment, and another variable

Is sample size important

Yes, larger sample sizes generally make results more reliable because they reduce the influence of random variation. Better represent the population, increase statistical power, and make it easier to detect real effects.

Sample size is supposed to be representation of the population

What does statistical analysis test for?

statistics helps determine whether an observed difference is likely due to a real effect, or could reasonably be explained by random variation

What is a T test?

A t-test compares means between groups and conditions

Unpair test is used when comparing to independent groups

For example, group one has the drug and group 2 has the placebo different individuals are in each group

Paired t test is used when observations are paired and dependent

An example is when you measure the same people before and after the treatment so that means they’re the same groups

What is a P value?

A p value helps a evaluate the null hypothesis

If P is smaller than 0.05 we say it is statistically significant, reject the null hypothesis and evidence supports a difference

If P is bigger than 0.05 We say it is not Statistically significant, Fails to reject the null hypothesis. There’s insufficient evidence for A difference

Difference between one tailed hypothesis and two tailed

One tailed Is for example, when you only care whether the drug changes blood pressure in one specific direction

Two tailed is when you care whether the drug causes any difference regardless of direction so it increases or decreases blood pressure

A one tail hypothesis predicts a specific direction of the effect like greater than or less than. Two tailed hypothesis does not predict a specific direction. You only predict that the group will be different.

A p value tells you how surprising your observed results would be if the null-hypothesis were true so one tailed P value looks at one side of the distribution a two tailed P value considers both sides of the distributions

Suppose you’re given a T test with P equals 0.03 if your hypothesis is treatment a is different from treatment B that’s a — tailed hypothesis

Two

X axis is the —- Variable and —- variable is the Y axis. X axis is usually the thing you —- and Y axis is the thing you —-

Independent, dependent, change, measure

What graphs should you use for different situations?

For comparing groups and categories use A bar graph

For continuous measurement, overtime use a line Graph

For relationships between two continuous variables, use a scatter plot. Relationship between two continuous variable means you have two numerical measurements and you want to see whether they are related to each other. Continuous variable is a numerical measurement that can have many possible values And you’re trying to ask when one measurement changes does the other measurement tend to change to?

Blind versus double blind studies

Blind study is when the participants do not know which treatment or group they are receiving which reduces participant bias

Double blind study is when neither the participants nor the researchers directly interacting and evaluating them know who receive which treatment during the study this reduces both participant bias and researcher bias

Is it easy to get research published?

No researchers send their manuscripts to an academic journal, which is a very rigorous process. You always need background like getting your PhD or masters and once you finish research, you write it up and submit it to a journal.

Before the scientist, review your paper a journal editor check that your paper meets basic quality standards

Then a group of 2 to 3 scientists review your paper known as peer review they don’t know who you are and you don’t know who they are kind of like a blind study

Based on this review, you’ll get the first decision which is rejected, major revision, minor revision, or accepted. It’s very rare to get accepted on your first submission

Then once you revise it, you might have to collect more data, conduct new analysis, and lots of writing, you will resubmit. The average paper goes through two rounds of review.

After publication your paper get cited by other researchers

Vast majority of research is collaborative and true seeking

Natural selection is a — that causes evolution and when an individuals are selected the — evolve

Mechanism, populations

What types of bonds can be found in water molecule

Polar covalent bonds

Within one H2O molecule the oxygen and hydrogen atoms share electrons so the bond is covalent

Oxygen pulls the electrons towards itself more strongly than hydrogen does so electrons are shared unequally

The bond becomes polar with oxygen being slightly negative and hydrogen is slightly positive

Inside one water molecule is polar covalent bonds

What types of bond is found between water molecules

Hydrogen bond

Slightly positive hydrogen of one water is attracted to slightly negative oxygen of another water molecule.

Inside H2O polar covalent and between H2O molecules are hydrogen bonds

Don’t say water molecules are held together by covalent bonds, covalent bonds hold the H and O atoms together within one molecule

What are the 4 important properties of water

The four properties you should know

1) cohesion

2) moderation of temperature

3) lower density upon freezing

4) water is a versatile solvent

These properties are a result of waters polarity and hydrogen bonding

What is cohesion

Attraction between molecules of the same substance

For water it’s water to water

Water molecules stick to each other because of hydrogen bonds

Cohesion helps water move as a continuous column through plants

What is adhesion

Attraction between different substances

Example is water to glass

Adhesion contributes to capillary action, helping water move through narrow spaces such as plant vessels

Cohesive properties lead to water having —- tension, which is ability to —- breaking or stretching which is acting like tight skin. importance of cohesiveness is water transport in —- because plants absorb water via their roots and so water travels in small little vessels called —- inside the xylem‘s water stick to each other, and they also stick to the wall of the xylem on surface of leaves are tiny little pores that allow for gas exchange so CO2 comes in and O2 leaves and water also leaves the pores, causing more water to be pulled up to the roots by this xylem

Surface, resist, plants, xylems

Cohesiveness also has drawbacks As premature babies are under —- distress due to cohesiveness because When babies are 37 weeks type two alveolar cells produces substance called —- which helps break up surface tension, and the cohesive property. If you didn’t have surfactant, your lungs wouldn’t be able to inflate when born.

Another drawback of cohesiveness is that the —- attraction between water molecules can make water resistance to being separated, so it takes a lot of —- to overcome the —- bonding

Respiratory, surfactants

Strong, energy, hydrogen

Temperature is measure of —- kinetic energy, which is —- energy. heat is ability of energy to —- between two different systems. the higher the temperature of something, the more —- energy, the faster things move. when bonds form heat —-and when bonds break, heat is absorbed

Mean, motion, pass, kinetic, releases

What is high specific heat

water requires a large amount of heat energy to change its temperature

Water has high specific because hydrogen bonding allows water to absorb a lot of energy without a temperature changing rapidly

This is important because your body contains a lot of water so water helps prevent your body temperature from changing too quickly

It’s important to the environment because oceans and lakes, absorb large amounts of heat and help moderate earths climate

The drawbacks are that water also take a lot of energy to heat up or cool down so it does not change temperature quickly when you want to

So significant is moderate and stabilizers environment and prevents drastic change in temp

What does it mean that water has unusual high specific heat?

More heat is required to raise the temperature of water

How many calories does it take to change 1 g of water by one Celsius?

1 Calorie, which is the amount of heat required to raise 1 g of water by 1°C. You could also say 1000 kcal.

Example to raise 5 g of water by 2°C you would multiply 5 g x 2° times 1 cal which is 10

Memorize 1 g water +1°C equals 1 cal

What is heat of vaporization and how is it a property of water?

Heat of vaporization is the specific amount of energy needed to turn a given quantity of a liquid into a gas at a constant temperature and pressure

For water it’s a significant amount of heat because at 100°C it is the boiling point of water

The significance of heat vaporization is evaporative cooling, which is water absorbing a large amount of heat from its surroundings as it turns into vapor which cools living bodies and helps maintain stable internal temperature

Water shows high cohesion and surface tension and can absorb large amounts of heat because of large numbers of

Hydrogen bonding

Density of water

most substances become denser when they become solid, but water is unusual when water freezes it expands the hydrogen bonds arrange water molecules into a more open structure. This makes solid ice less dense than liquid water therefore ice floats.

The significance of ice being less dense than water is very important for aquatic ecosystems imagine a lake during winter if I were denser than liquid water ice would sink and more water would freeze eventually much of the lake could freeze solid. This would make survival extremely difficult for aquatic organisms instead the ice floats on top forming an insulating layer in the water underneath remains liquid.

The drawbacks or is that water can cause physical weathering so water enters cracks in rocks. It freezes and expands , and pressure is placed on the rock. So water expanding when it freezes can cause damage to structures like cracked roads

Water as a versatile solvent

Water is a very effective solvent because it is polar. It has a slightly negative oxygen and a slightly positive hydrogen and these partial charges allow water to interact with ions and polar molecules. Take away is that water can dissolve ionic and polar molecules very easily.

A solute is a substance being —-, a solvent is a substance — the dissolving a solution is a —- mixture of solute and solvent. An aqueous solution is when water is the —-

Dissolved, doing, homogenous, solvent

Why can water dissolve ionic compounds?

Consider NaCl that has Na and Cl ions. Water has partial charges the slightly negative oxygen is attracted to Na. The slightly positive hydrogen is attracted to Cl Water molecule surround the ions and help separate them therefore, water can dissolve many ionic compounds

Why can water dissolve polar molecules?

Polar molecules have partial positive and negative regions and because water is also polar water can form favorable interactions with them and remember the general rule that like dissolved like

While water being a versatile solvent is good because it allows many substances to move through organisms and participate in chemical —- so it allows biological reactions and transport to occur. It also has drawbacks because water dissolve so many substances it can also dissolve —- substances like toxic chemicals, allowing contaminants to spread through water and potentially enter organisms and ecosystems.

Reactions, harmful,

The biggest Takeaway of what causes water to have these unique properties is that water is —- and water molecules form —- bonds with one another the hydrogen bonding contributes to cohesionm high specific heat , and ice unusual density and water’s polarity allows it to interact with ions and attract with polar molecules and act as a versatile solvent

Polar, hydrogen,

What does pH measure?

pH is a measure related to the concentration of hydrogen ions in a solution

The more hydrogen ions pH decreases

The less hydrogen ions pH increases

Remember it as a inverse relationship

You can calculate pH by negative log and then in the parentheses the concentration of hydrogen ions

What is an acid and base? What is a buffer?

An acid increases the concentration of hydrogen ions in a solution. They donate hydrogen.

A base decreases hydrogen concentration often by accepting them so it raises the pH

A buffer is a system that resist changes in pH. It doesn’t prevent pH from changing instead of reduces the magnitude of the pH change. proteins are the biggest buffers we have in our body so either buffers except hydrogen ions when there’s too much or they can also donate hydrogen ions when there’s not enough.

Because the pH scale is a log scale, between each value is a factor of — for example if grapefruit juice is a three on the pH scale and tomato juice is 4 grapefruit. Juice has 10 times more —- ions or tomato Juice has 10 times more —- ions.

Another example is lemon. Juice is a two on the pH scale and tomato juice is a four so lemon juice has —- times more hydrogen ions because we don’t add we multiply by 10.

Last example is comparing acidic solution at pH 5 to a basic solution at pH eight so the difference is three meaning there are —- times less hydrogen ions in the basic solution

10, hydrogen, hydroxide

100

1,000

Let’s say you have a beaker that goes from 0 to 7 to 14. Arrow A is from 7 to Arrow b is from 7 to 14 arrow C is from 0 to 7 And Arrow D is from 14 to 7

if you’re progressing from A weak acid to a strong acid which arrow would that be?

If you’re progressing from a weak base to a strong base, which arrow is that

Which arrow is the result of adding more hydrogen to a solution?

A, B, A and D

What is the carbonic acid bicarbonate buffer system?

The reaction is carbonic acid arrow on both sides, hydrogen plus bicarbonate

The reaction can move in either direction

What happens when blood becomes too acidic or basic?

Two acidic means hydrogen ions is too high, and the buffer system can use bicarbonate to remove some of the excess hydrogen ions by binding to Them and creating Carbonic acid, then be carbonic acid can ultimately be converted into carbon dioxide and water

The lungs can exhale carbon dioxide, so blood becomes acidic, hydrogen ion. Concentration rises then bicarbonate binds to the hydrogen ions and carbonic acid is formed. Carbon dioxide is produced when weak carbonic acid dissociates. The carbon dioxide is exhaled hydrogen ion decreases, and pH move towards normal.

When blood becomes too basic hydrogen ion, concentration is low carbonic acid can dissociate into hydrogen ions and bicarbonate, which increases the H plus so pH again moves towards normal

The normal blood pH is 7.4+ -0.05

How is the carbonic acid bicarbonate system a negative feedback mechanism

If blood becomes to acidic the body responses to decrease hydrogen ions and pH returns towards normal, so the response counteract the original change

If blood becomes too basic the body response to increase hydrogen ions and the pH returns towards normal so again the response counteract the original change