bio lab test 

Steps of Scientific Method

  • Ask a question

  • Do research

  • Conclude a hypothesis

  • Do an experiment

  • Analyze the data and draw a conclusion

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Null hypothesis-  a statement that proposes that there is no difference or relationships between variables.

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Alternative hypothesis- is a statement that proposes that there is a difference or relationships between variables. In other words, the alternative hypothesis is what is proposed to be true if the null hypothesis is false.

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Hypothesis- is a testable scientific idea that can be supported or refuted with the collection of data.

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Independent variable - variable that is manipulated or controlled

Example- A scientist wanted to determine the color flower that bees are most attracted to. She placed different colors of the same type of flower near each other and counted the number of bees that visited the flower. What is the independent variable? A- color of flower

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Dependent variable- which may change due to the independent variable (is being measured)

Example- Scientists wanted to determine the levels of pollution that a fish could withstand. They placed fish in tanks with differing pollution levels and timed how long they could live under those conditions. What is the dependent variable? A- Amount of time before death

The x-axis of a graph is always your independent variable, and the y-axis is the dependent variable.

Control group- The group that is used as the basis for comparison and is not subject to the experimental treatment.

Example: a plant set in a room with no light bulb

Experimental group-  is subject to the experimental treatment

Example: a plant set in a room with 10 light bulbs \n Controlled Experiment - compares an experimental group with a control group

Inductive Reasoning - We go from specific to general

Example- Harold is a grandfather. Harold is bald. Therefore, all grandfathers are bald.

Deductive Reasoning-  Prediction produced from a general statement; usually “if-then” form

Example- All humans are mortal. (premise) John Smith is human. Therefore, John Smith is mortal

List the proper order for bringing an object into focus with the compound light microscope

  • Turn on the light source and adjust the brightness

  • Put the objective on 4x objective

  • Adjust ocular lenses to view one image

  • Turn the fine adjustment and coarse adjustment  knob so that you can see the object clearly

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Describe how the letter e appears and moves as visualized by the compound light microscope

  • When we put the e on the stage it will flip the e upside down and backward. When we move the stage it will go in a different direction instead of going right when u moved it right it will go left

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Identify the substance, indicator, and color change of different qualitative tests of macromolecules

Starch using iodine - yellow orange= negative black= positive

Protein using Biuret- lavender = positive  blue= negative

Glucose using  benedict- light blue = negative yellow orange = positive

Chlorine using Silver Nitrate - white precipitate

Sulfate using Barium Chloride- milky white

Dehydration reaction-

Starch - Glycosidic Linkage

Protein - peptide bond

Glycosidic linkage- a covalent bond formed between two monosaccharides by dehydration reaction \n

polypeptide -many amino acids linked by peptide bonds

Primary Structure - Linear sequence of amino acids.

Secondary Structure- Coils and folds because of the hydrogen bonds between the repeating polypeptide backbone.

Tertiary Structure Bonds stabilizing tertiary structure between side groups:

Quaternary Structure Protein structure contains more than one amino chain

Facilitated diffusion- passive transport that allows substances to cross membranes with the assistance of special transport proteins

Simple diffusion- the movement of a solute from an area of high concentration to an area of low concentration

Passive transport- The movement of materials through a cell membrane without using energy

Active transport- the movement of materials through a cell membrane using energy

Hypertonic- Having a higher concentration of solute than another solution.

Isotonic- Having the same solute concentration as another solution.

Hypotonic- Having a lower concentration of solute than another solution

Turgid plant cell- A cell that is swollen with water (hypotonic)

plasmolyzed plant cell- hypertonic solution

red blood cells in isotonic- do not change

hypertonic blood cells- shrivel up as water diffuses out of them

hypotonic blood cells- swell up as water diffuses into them

Protein and Starch- substances that can't diffuse through cell membranes

ester linkage- the bond between a fatty acid and glycerol that forms a lipid

Osmosis- Diffusion of water through a selectively permeable membrane

the characteristics of enzymes-

Are not used up in a reaction

Combine with substrates

Speed up the rate of a reaction

Substrate -reactant of an enzyme-catalyzed reaction ex- hydrogen peroxide

Enzyme- a protein that acts as a biological catalyst

Product in a reaction- the new important substance formed by a chemical reaction

How do enzymes work -

  • Enzyme is the lock, and the key is the substrate. Keys are substrates that fit into the lock and then react.
  • Active Site – where substrates bind and react. This is where catalysis occurs
  • Enzymes are flexible. They go under a significant change in shape when reactant molecules bind to the active site. This change is known as the induced fit.
  • Activation energy- the minimum amount of energy required to start a chemical reaction

Cofactor – atoms or molecules that are not part of the enzyme’s structure but are non-protein helpers needed for the enzyme to function normally for catalytic activity.

They can be: -metal ions ex. Zinc or Magnesium

Coenzymes - non-protein and organic molecules which bind temporarily or permanently to enzyme near active site

Describe how low and high temperatures and pH affect the shape of a protein and the rate of an enzymatic reaction

  • High Temperature = Speed of enzymatic reaction drops sharply.

Losses its shape

  • Low Temp= molecules move slower,  decrease collisions

Flexibility is lost

  • Ph = will affect the charges on the amino acid molecules.
  • At low pH H+ ions interfere with bonds that maintain the enzyme’s shape • At high pH OH ions interfere with the enzyme’s shape

Why did we use guaiacol as a substrate to measure turnip root peroxidase?

  • It indicates that peroxide is broken down to → H2O.
  • Peroxidase enzyme catalyzes turning brown also indicates enzyme activity. –When guaiacol is acted on by the enzyme it changes colors to brownish as it is oxidized.

Why did turnip peroxidase increase in activity from 0° to 37 ° Celsius?

-At higher temperatures, there is an increase in kinetic energy, fast molecular collisions, and more changes for the enzyme to collide with a substrate and react with each other.

Why did turnip peroxidase decrease in activity above 37° Celsius?

  • Because after 37° it comes denatured.