Biology - Assesment #1

independent variable 

what is being manipulated (x axis)

ex: amount of light (hours per day)

what you changed

dependent variable

effect/result due to the manipulation (y axis)

ex: plant growth (cm)

what you measured

Purpose of constants

factors you control or hold constant so that they can’t influence the experiment.

Control variables are important because:

• They make it easier to reproduce the experiment.

• The increase confidence in the outcome of the experiment.

• allow only IV to affect DV

ex: water, soil, temp, day/night time

Constant meaning

What doesn’t change in the expirement (constant = control) 

p-value

Low p = Legit (real effect)

•  (usually < 0.05)

High p = Happens by chance

•  (usually > 0.05)

standard error

how much smth varies around x average

• Short error bars → data is more reliable (less spread out).

• Long error bars → data is less reliable (more spread out).

• If error bars from two groups don’t overlap, the difference is probably real.

• If they do overlap, the difference might just be chance.

error bars = show how much we trust the average. ( +/-2SE)

open ended questions

multiple answers / needs explations

closed ended questions

can be answered w/ a single word [yes/no]

hypothesis

A hypothesis is a theory about what will concur in an experiment.

• If… → you say what you are changing (independent variable).

• Then… → you say what you think will happen (dependent variable).

• Because… → you explain why you think it will happen.

Describe the special bonding properties of carbon that allow it to form an endless variety of organic molecules.

Carbon can form an endless variety of organic molecules because…..

1. Tetravalent

   • Carbon has 4 electrons in its outer shell, so it can form 4 covalent bonds with other atoms (including other carbons).

2. Bonds with Many Elements

   • Carbon can bond with many elements

   • This variety creates diverse organic molecules like sugars, fats, proteins, and DNA

3. Single, Double, and Triple Bonds

   • Carbon can form single (C–C), double (C=C), or triple (C≡C) bonds, giving different shapes and reactivity.

4. Carbon atoms can bond to each other in long chains, branched chains, or rings.

   • This property allows the formation of huge molecules like polymers and macromolecules.

Because of these bonding properties, carbon is the backbone of life

Compare a dehydration reaction to a hydrolysis reaction.

Monomers (amino acids) are linked together to form polymers (protein consisting of multiple monomers) by removing a water molecule through a process called dehydration synthesis. To break down those polymers into monomers by adding a water molecule, a process called hydrolysis occurs. 

Compare the structures and roles of monosaccharides, disaccharides, and polysaccharides in living organisms. Give examples of each.

monosaccharides

• single sugar carbohydrates

structures: straight-chained/ ring-shaped

• quick energy source & can act as building blocks for carbs

examples: glucose 

disaccharides

structures: 2 monosaccharides linked together by a bond 

• essential for photosynthesis in plants & nourishment in mammals

examples: lactose

polysaccharides

structures: multiple monosaccharide units bound together (more complicated/harder to break up)

• large carbs polymers that serve as energy storage

example: cellulose 

Describe the unique properties of lipids

• lipids = hydophobic (phospholipid bilayer example w/ tails)

• energy: 1b of lipids has nearly 2x energy as an lb of carbs (fuel for the body)

• structure: form in long chains of fatty acids (twists/straight)

Compare the structure and properties of saturated and unsaturated fatty acids.

Unsaturated:

• shape: bent by double bond → create kinks in chain

• fatty acids (found in nuts)

Saturated:

•  straight (no double bonds)

• can be long/short

Distinguish between steroids and anabolic steroids, and explain how the use of anabolic steroids can be dangerous to a person’s health.

steroids (natural)

• lipids containing 4 fused rings

• cholestrol (common in cell mebrane) used as starting material for steroids

anabolic steroids (synthetic ver of testrone)

• buildup of muscle + bone mass

• smaller testicles

• infertility

Describe the structure of proteins, and explain how the structure of a protein relates to its function.

structure: chain of animo acids strung together → as protein develops can begin to devlop folds which tranform it into 3 types of structures: secondary, tertiary, or quaternary ( hemoglobin: a quaternary structure that carries oxygen)

function: as it grows it need to be able to help transport proteins + send protein signals throughout the body