Homeostasis, Biomolecules, and Evolution

• Study notes on homeostasis, biomolecules, and evolution.

Passive Transport

• This process involves molecules moving across cell membranes without requiring energy input.

Simple Diffusion

• Molecules move from an area of high concentration to an area of low concentration.
• Movement occurs down the concentration gradient.

Facilitated Diffusion

• Molecules move down the concentration gradient.
• This movement is aided by a protein.
• Energy is not required.

Osmosis

• Water molecules move from areas of low solute concentration to areas of high solute concentration.

Hypotonic Solution

• The cell in this solution will grow because the solution is less concentrated than the cell.

Hypertonic Solution

• The cell in this solution will shrink because the solution is more concentrated than the cell.

Isotonic Solution

• The cell's concentration is equal to the solution's concentration.
• The cell size remains the same.

Active Transport

• Molecules move across cell membranes.
• This process requires energy in the form of ATP.

Endocytosis

• Large molecules are engulfed and taken into the cell by the cell membrane.

Exocytosis

• Molecules are expelled from the cell through the cell membrane.

Carbohydrates

• Quick energy is provided by carbohydrates, which also store energy and provide structural support.

Carbohydrate Monomer

• Monosaccharides are the building blocks of carbohydrates.

Carbohydrate Example

• Potatoes are an example of a carbohydrate.

Proteins

• Proteins function as catalysts, provide support, and aid in transport.

Protein Monomer

• Amino acids are the building blocks of proteins.

Protein Example

• Enzymes are an example of proteins.

Lipids

• Lipids make up the cell membrane, provide long-term energy storage, regulates diffusion.

Lipid Monomer

• Lipids are composed of glycerol and three fatty acids.

Lipid Example

• Butter is an example of a lipid.

Nucleic Acids

• They carry genetic code and conduct protein synthesis.

Nucleic Acid Polymer

• The polymer is nucleotides (ATGC or AUGC).

Nucleic Acid Example

• DNA and RNA are examples of nucleic acids.

Nucleotide Components

• A nucleotide consists of a phosphate group, a nitrogenous base, and a sugar.

Base Pairing Rule

• Adenine (A) pairs with Thymine (T).
• Cytosine (C) pairs with Guanine (G).

Antiparallel Strands

• DNA strands run in opposite directions, denoted as 5'-3' and 3'-5'.

Double Helix Shape

• The sides of the helix are composed of phosphate groups and sugars.
• The rungs are formed by nitrogenous base pairs.

Gene

• A segment of DNA that influences a particular trait.

Variations in Nucleotide Sequences

• These variations allow for differentiation between species and diversity within populations.

DNA Structure

• The structure is common amongst all living organisms.

Fossil Evidence

• Fossils are preserved traces or remains found in rock.
• Younger fossils are found in younger rocks.

Biogeography

• The study of the distribution of species and ecosystems over geological time and space.

Homologous Structures

• Structures in different species that look similar but have different functions.

Analogous Structures

• Structures in different species that have similar functions but different structures, does not show common ancestry.

Vestigial Structures

• Structures that had a use in the past but are no longer in use, such as the appendix.

Molecular Homology

• Biomolecular studies comparing nucleotide sequences.
• More similarities indicate a closer relationship between species.

Embryology

• Similarities exist in the features of embryos of different species.

Common Ancestor

• A species from which most life descended.

Stasis

• Long periods of time without evolutionary change.

Punctuated Equilibrium

• Quick periods of evolutionary change are followed by long periods without change.

Gradualism

• Slow, gradual change over time.

Stomata

• Structures used during photosynthesis for gas transfer.

Xylem

• Transports water from the roots to the leaves.

Phloem

• Conducts sugars from the leaves throughout the plant.

Root System

• The underground part of the plant anchors it.
• Absorbs water and stores food in the cortex.

Sepal

• Protects the flower before it blooms.

Stamen

• The male structure of the flower.

Pistil

• The female structure of the flower.

Asexual Reproduction

• Involves the shoot system (e.g., potato).

Sexual Reproduction

• Contains a genetic combination of both parent plants.
• It typically results in the formation of fruit.

Auxin Hormone

• Causes phototropism (growth in response to light).

Positive Gravitropism

• Roots grow down in response to gravity, seeking minerals.

Negative Gravitropism

• Shoots grow upward, against gravity, to obtain light.

Thigmotropism

• A growth response in plants when they come into contact with an object.