BIO Unit 1 Exam Study Guide

What are Electrons, Protons and Neutrons? What are their relative sizes and charges?

Electrons are negatively charged particles that circle outside of the nucleus. Protons are positively charged particles that are in the nucleus. Neutrons are no-charge particles in the nucleus. Protons and neutrons are approximately the same mass. Electrons are a lot lighter than protons and neutrons.

Which subatomic particle (electron, proton or neutron) defines an Atom's identity?

Protons.

How do electrons act during the chemical interactions between atoms?

They are either shared or transferred.

What is a shared electron pair? What kind of bond is made when electrons are shared? Is this bond strong or weak?

A shared electron pair occurs when atoms need to satisfy or stabilize themselves by filling up their outermost shell by sharing an electron with another atom. This is called a covalent bond and it is a strong bond.

What is a Hydrogen Bond?

A hydrogen bond is the attraction between two opposing, partially charged particles.

What is the structure of Water? Why is it Polar?

Water contains one oxygen and two hydrogens. It is polar because the oxygen is a lot more electronegative than the hydrogen, which causes the oxygen to have a partial, negative charge and the hydrogens to have a partial, positive charge.

What do the terms Hydrophilic and Hydrophobic mean?

Hydrophilic means it likes water and can dissolve in it. Hydrophobic means it hates water and can’t dissolve in it.

What is pH and how is it calculated?

pH is the measure of how acidic or basic a solution is based on the concentration of H+ ions. The lower the pH, the more acidic. The higher the pH, the more basic or alkaline the solution is. This is calculated by taking the negative logarithmic of the concentration of H+ ions.

What is Polymerization?

Polymerization is putting two or more subunits or monomers together using covalent bonds.

What is a Dehydration reaction?

When the OH and H from respective atoms are taken out as a water molecule (H2O) and the two molecules become covalently bonded.

Hydrolysis (Digestion Reaction)

A water molecule breaks the covalent bond between two molecule and separates them.

What is a Lipid?

A lipid is a biomolecule that is either hydrophobic or amphipathic.

What is the structure of a Fatty Acid? What is Glycerol? How do Fatty Acids attach to Glycerol to make Fats/Oils?

The structure of a fatty acid consists of a long hydrocarbon chain with an acidic head (carboxyl group). Glycerol is the backbone of triglycerides and membrane lipids. Fatty acids attach to glycerol to make fats/oils through a dehydration reaction.

What is required for a molecule to be polar?

To have an unequal sharing of electrons and to have a bent shape.

In most organic molecules, how many covalent bonds does carbon form with other molecules?

4

How many covalent bonds does each oxygen typically make?

2

How many covalent bonds does hydrogen typically form?

1

What is the structure of a Phospholipid?

The structure of a phospholipid contains a hydrophilic head facing the outside of the cell and a hydrophobic tail facing towards each other.

How are Phospholipids oriented in the Lipid Bilayer? Why is this a good structure for providing a boundary to the cell?

In a lipid bilayer, the hydrophilic head faces the outside of the cell while the hydrophobic tail faces towards each other to avoid water. This is a good structure for providing a boundary to the cell because it keeps most of molecules out, with only nonpolar molecules able to get in. Polar and ion molecules cannot easily cross without help.

What is the basic structure of an Amino Acid?

Amino group, carboxyl group, and R group (side group/chain) attached to a carbon.

What is meant by the “Side group” of an Amino Acid; i.e., what makes different Amino Acids different from each other? How many different Amino Acids are used to make Proteins?

The side groups of an amino acid is what makes each amino acid different from each other. There are 20 different possible side groups that gives the amino acid a unique property and identity.

What is the Plasmamembrane of a cell? Which two types of biomolecules is it made of?

The plasmamembrance of the cell is the boundary of the cell that keeps its internal contents separate from the outside world. The two biomolecules that it is made out of is proteins and lipids.

What is the subunit of DNA? What is the DNA backbone made of?

The subunit of DNA is a nucleotide. The DNA backbone is made out of alternating sugar and phosphate that is joined by a covalent bond through dehydration.

What is a DNA Base? How do the different Bases pair with each other? How does this Base-Pairing make copying the DNA possible?

A DNA base is a building block that attaches to the DNA backbone to form the genetic code for an organism. Adenine pairs with Thymine (Uracil in RNA). Guanine pairs with Cytosine. The different bases pair with each other through hydrogen bonding. This base pairing makes copying DNA possible because it allows DNA to store genetic information that can be used to make daughter cells with accurate DNA copies.

What are Monosaccharides and Polysaccharides? How do Sugars Polymerize into larger carbohydrates?

Monosaccharides are the monomers of carbohydrates. Polysaccharides are long chains of monosaccharide, basically the polymers of carbohydrates. Sugars polymerize into larger carbohydrates through dehydration, where monosaccharides form covalent bonds and soon form a long chain.

What are some of the uses for Polysaccharides in cells?

Storage like starch in plants and glycogen in animals. Builds strong structure like cellulose builds cell walls.

Which polymers are exclusively made of Glucose?

Cellulose, glycogen, starch.

The vast majority of the functions of a cell are performed by which of the four major types of biomolecules?

Proteins.

What is Cell Theory? Where do all new cells come from?

The cell theory states that all biological organisms are made up of at least one cell; cells are the basic unit of function, and that new cells come from the division of other cells.

What structure is the Boundary of the Cell?

Cell membrane.

What is a Membrane made out of? What gives a membrane its function?

A cell membrane is made out of phospholipid bilayer, which are made up of phospholipids. Proteins gives the cell membrane its function.

What are the functions of Ribosomes?

Makes proteins and helps chain amino acids.

What are the basic structures present in a Bacteria?

Cell membrance, cell wall, ribosomes, DNA.

What do the words Prokaryote and Eukaryote mean?

Prokaryote are single celled organisms that have no nucleus membrane and don’t contain all organelles. This word also means “before” “nut” AKA they existed before cells developed a nucleus. Eukaryotes are multi-celled organisms that contains all organelles. This word means “true” “nut” because it has a nucleus.

Smooth ER

in charge of making phospholipids.

Rough ER

In charge of making membrane proteins.

Golgi Bodies

Modifies, sorts, and packages proteins for delivery to other organelles.

Nucleus

Stores the cell’s DNA and controls cell’s activities by regulating gene expression.

Vesicles

Transports and stores materials within cell.

Chloroplasts

Carries out photosynthesis to produce glucose for plant.

Mitochondria

Produces ATP (energy) for the cell through cellular respiration.

What is the Endosymbiosis Theory regarding Mitochondria and Chloroplast organelles? What is the (most-likely) origin of the Mitochondria and Chloroplast organelles?

Mitochondria and chloroplasts evolved from free-living bacteria and formed a symbiotic relationship with eukaryote cells. The most likely origin of these two organelles are bacteria.

What features of Chloroplasts and Mitochondria support the Endosymbiosis theory?

Features that support this are: mitochondria and chloroplasts are only formed from division of existing M and C, both have small circular DNA chromosome with DNA sequence similar to bacteria, have bacterial-like ribosomes, and strongly resemble bacteria.

How are Chloroplasts and Mitochondria created? Do they have their own DNA?

Chloroplasts and mitochondria are created from division of existing C and M. They have small circular DNA chromosome.

What are the four types of signaling mechanisms in multicellular organisms?

1. Autocrine = the signaling molecule targets its own cell.

2. Signaling across gap junctions = the signaling molecule targets cell connected by gap junctions.

3. Paracrine = the signaling molecule targets a nearby cell.

4. Endocrine = the signaling molecule targets a distant cell through a bloodstream.

What are internal and cell-surface receptors? How are they similar and different?

Internal or intracellular receptors bind to ligands within the cell. Cell-surface or extracellular receptors bind to ligands outside of the cell. They are similar in which they both bind to specific ligands and cause a response within the cell. Internal receptors mainly focus on regulating gene expression within the cell. Cell-surface receptors focus on detecting external signals, passing it to internal part of cell, then causing a rapid response.

What is a ligand, and how does its structure affect its function?

A ligand is a small molecule, ion, or protein that binds to a receptor. The shape and structure of a ligand determines what kind of receptor they will bind to.

What are the ways that signal transduction occurs after ligand binding?

After ligand binding, the receptor changes slightly internally which then starts a signal within the cell that will eventually lead to a response.