Comprehensive Guide to Memory, Cell Structure, and Photosynthesis in Biology

What are the two main types of memory?

Short-term memory (STM) and long-term memory (LTM).

What is the duration and capacity of short-term memory?

Seconds to minutes with limited capacity (approximately 7 items).

What happens to information in short-term memory if it is not used?

It is released or forgotten.

What characterizes long-term memory?

It has infinite duration and capacity and is activated when information needs to be retained.

What is the principle 'use it or lose it' in relation to memory?

If information is not actively recalled or used, it may fade away.

What is Long Term Potentiation (LTP)?

A lasting increase in the strength of synaptic transmission that facilitates memory and retrieval.

What role do synapses play in memory formation?

Synapses change in strength or number as new memories are formed.

What is neuron plasticity?

The ability of the nervous system to modify itself after birth, enhancing learning and memory.

How does activity affect synapses?

High activity strengthens synapses, while low activity weakens or eliminates them.

What is the difference between memory and learning?

Memory is the storage of information, while learning is the application of that information to improve actions.

What is the significance of organization in memory retention?

Grouping related information (chunking) aids in memory formation.

What is the scientific method?

A systematic process of testing hypotheses to develop knowledge about the natural world.

What is a hypothesis?

A testable proposed explanation based on available data.

What is a prediction in the context of scientific inquiry?

An expected outcome when testing a hypothesis.

What is the definition of a theory in science?

A broad explanation supported by significant evidence that leads to new hypotheses and accurate predictions.

What is a scientific law?

A statement describing what always occurs under certain circumstances.

What are emergent properties in biology?

Properties that arise from the arrangement and interaction of parts within a system, where the whole is greater than the sum of its parts.

What is the unifying idea of biology according to T. Dobzhansky?

All living organisms are modified descendants of common ancestors.

What are the levels of biological organization?

Biosphere, ecosystems, communities, populations, organisms, organs and organ systems, tissues, cells, organelles, molecules.

What is the role of neurotransmitters at a synapse?

They are chemicals that transmit signals across the synapse from one neuron to another.

What happens to synapses when a memory is recalled?

The connections between neurons strengthen, which is a process known as long-term potentiation (LTP).

What is the flow of information in memory formation?

Stimulus → Neuron fires → Synapse changes → Memory → Recall → Learning.

What is the impact of practice on memory?

Regular practice strengthens synapses, leading to better memory retention.

How does the brain use long-term memory?

The brain retrieves information from long-term memory and brings it into short-term memory for use.

What is the relationship between neurons and signals?

Neurons send signals to process information, feel emotions, move, and remember.

Why is memory considered a change in synapse?

Memories are stored as patterns of stronger/weaker connections between neurons, not as static files.

What is the first step in the scientific process?

Observation & Question

What follows after generating a hypothesis in the scientific process?

Make predictions

What is the role of experiments in the scientific process?

To test the predictions

What are the main elements in biological molecules?

Oxygen (O), Carbon (C), Hydrogen (H), Nitrogen (N)

What are the subatomic particles that make up an atom?

Protons, neutrons, and electrons

What charge do electrons carry?

-1 charge (negative)

What determines the potential energy of an electron?

Its distance from the nucleus

What are valence electrons?

Electrons in the outermost shell of an atom

What is a molecule?

A compound of 2 or more atoms held together by chemical bonds

What is the chemical formula for water?

H2O (2 hydrogen, 1 oxygen)

What is electronegativity?

A measure of an atom's affinity for electrons

What type of bond involves the sharing of electrons?

Covalent bond

What is a polar covalent bond?

A bond with unequal sharing of electrons, causing partial charges

What occurs in ionic bonds?

Electrons are lost or gained, resulting in charged atoms

What are Van der Waals interactions?

Weak interactions due to electron position and motion

What is a hydrogen bond?

An interaction between a partial positive charge on hydrogen and a strongly electronegative atom

What are the emergent properties of water due to hydrogen bonds?

Cohesion, adhesion, high specific heat, expansion when frozen, and being a universal solvent

What is the significance of carbon in biological molecules?

Carbon can form four bonds, allowing for complex molecules

What is a functional group?

A specific group of atoms within a molecule that is responsible for the characteristic reactions of that molecule

What is a monosaccharide?

A single sugar molecule, the monomer of carbohydrates

What is the approximate ratio of elements in carbohydrates?

CH2O

What is the process of synthesizing a polymer called?

Dehydration reaction

What is the enzyme involved in hydrolysis?

Hydrolases

What is the role of dehydrogenases?

To synthesize polymers by removing water

What is the basic structure of an amino group?

A nitrogen atom bound to two hydrogen atoms (-NH2)

What is the function of a phosphate group in biological molecules?

It can release protons and is found in phospholipids and nucleic acids

What are polysaccharides?

Polymers of hundreds to thousands of monosaccharides connected by glycosidic linkages.

What are the two main functions of polysaccharides in cells?

Storage (e.g., starch, glycogen) and structure (e.g., cellulose, chitin).

What are lipids and how do they differ from other macromolecules?

Diverse, hydrophobic molecules that are not polymers and do not dissolve in water.

What are the three main families of lipids?

Fats, phospholipids, and steroids.

What is the structure of fats?

Composed of glycerol and 1, 2, or 3 fatty acids.

How much energy do fats provide?

9 calories per gram, compared to 4 calories per gram for carbohydrates and proteins.

What is the structure of phospholipids?

Glycerol, 2 fatty acids, and a phosphate group, making them amphipathic.

What is the basic structure of amino acids?

Central carbon, hydrogen atom, amino group, carboxyl group, and a variable R group.

How are amino acids linked together?

By peptide bonds formed through dehydration reactions.

What is a polypeptide?

A chain of many amino acids (100+) joined by peptide bonds, not yet a protein until folded correctly.

What are the four levels of protein structure?

Primary, secondary, tertiary, and quaternary structure.

What causes protein denaturation?

Loss of native structure due to pH, salt concentration, or high temperature.

What are the functions of proteins?

Structure, signaling, enzymes, defense, and transport.

What are nucleic acids and their two classes?

Macromolecules that store and transmit genetic information; classes are DNA and RNA.

What are hydrocarbons?

Organic molecules consisting only of carbon and hydrogen, typically nonpolar and hydrophobic.

What are functional groups?

Groups of atoms attached to carbon that replace hydrogen and affect molecular function.

What is the hydroxyl group?

A polar, hydrophilic group found in alcohols, consisting of an oxygen bound to a hydrogen.

What is the carboxyl group?

A group that can release a proton (H+), making it acidic; important in amino acids and fatty acids.

What is the amino group?

A basic group that acts as a proton acceptor, found in amino acids.

What is the phosphate group?

An acidic, hydrophilic group involved in nucleic acids and ATP, consisting of phosphorus bonded to oxygen.

What is the methyl group?

A nonpolar, hydrophobic group that can affect gene expression in DNA.

What is dehydration synthesis?

A reaction that builds larger molecules by removing water, often used to synthesize polymers.

What is hydrolysis?

A reaction that breaks down polymers into smaller molecules by adding water.

What are the four classes of biological macromolecules?

Carbohydrates, lipids, proteins, and nucleic acids.

What is the approximate ratio of carbon, hydrogen, and oxygen in carbohydrates?

Typically represented as CH2O.

What is the role of functional groups in biological macromolecules?

They affect the chemical properties and functions of the molecules.

What are the two main types of cells?

Prokaryotic and Eukaryotic cells

What is the smallest unit that carries out all activities associated with life?

The cell

What is the meaning of 'prokaryote'?

Before nucleus

What is the size range of prokaryotic cells?

1-10 micrometers

Where is the DNA located in prokaryotic cells?

In the nucleoid region

What structure surrounds all cells?

Plasma membrane

What is the meaning of 'eukaryote'?

True nucleus

What is the size range of eukaryotic cells?

10-100 micrometers

What organelle is responsible for making ATP?

Mitochondria

What is the function of chloroplasts?

Responsible for photosynthesis

What is the evidence for endosymbiosis?

Double membranes, similar size and morphology to bacteria, and DNA sequences similar to bacteria

What is the role of the endomembrane system?

To organize and compartmentalize cellular functions

What is the function of lysosomes?

Contain hydrolytic enzymes for digestion

What is the difference between vacuoles and vesicles?

Vacuoles are larger and longer-lasting; vesicles are usually for transport

What is the role of the rough endoplasmic reticulum?

Synthesis of proteins due to the presence of ribosomes

What is the role of the smooth endoplasmic reticulum?

Lipid synthesis and metabolism

What is the significance of the surface area to volume ratio in cells?

Smaller cells maximize surface area for efficient transport of materials

What is the function of the Golgi apparatus?

Modifying and packaging proteins for transport

What is the internal environment of a cell?

Different from the external environment, maintained by the plasma membrane

What is the function of ribosomes?

To synthesize proteins

What is the nuclear envelope?

A double membrane that surrounds the nucleus

What are nuclear pores?

Regulated openings in the nuclear envelope that allow substances to enter and exit the nucleus