LECTURE 2 - The Chemistry of Life Flashcards
Describe the properties of living organisms.
Order
Energy processing
Sensitivity/response to stimuli
Reproduction
Growth/development
Regulation/homeostasis
Adaptation
Evolution
SAROGHEE
What are the essential elements for life?
- Carbon – C/C
– Hydrogen – H/H
– Nitrogen – N
– Oxygen – O - Smaller amounts
– Phosphorous – P
– Sulfur - S
CHOPSN
polar/hydrophilic DEFINITION
partly or fully charged/with a dipole
water liking/soluble in water
non-polar/hydrophobic
water hating/insoluble in water
what is the difference between hydrophobic and hydrophilic molecules?
Hydrophobic = mainly of carbon and hydrogen (C/H), are nonpolar and do not have a charge.
Hydrophilic molecules = often contain (O), (N), (P), and sometimes (S), tend to be polar or partially charged.
The presence of polar or charged groups in hydrophilic molecules allows them to interact with water molecules through hydrogen bonding or other polar interactions.
What are the main differences between prokaryotes and eukaryotes?
Pro : single-celled organisms, no nucleus, circular DNA molecule, smaller and simpler in structure, lack membrane-bound organelles
Eu : can be single-celled or multicellular, with nucleus in the nucleolus, larger and more complex, contain membrane-bound organelles
What is homeostasis and why is it important for living organisms?
Maintenance of a relatively constant internal environment
- it allows organisms to adapt and respond to changes in their environment, ensuring their survival.
- enables cells and organs to function optimally
How does life capture and convert energy
Photosynthesis used by plants, algae, and some bacteria : capture energy from the Sun and convert it into chemical energy.
Cellular respiration : energy is obtained by consuming organic matter in the form of food –> ATP + glucose
How is genetic material shared between generations
Inheritance = encoded in molecules that carry the instructions for the development, functioning, and reproduction of living organisms.
The genetic material, primarily DNA (deoxyribonucleic acid), is passed from parents to offspring during reproduction.
In sexually reproducing organisms, genetic material is shared through the combination of genetic material from two parents. Each parent contributes half of their genetic material, which is contained in specialized cells called gametes (sperm and egg cells). During fertilization, the gametes fuse, combining their genetic material to form a new individual with a unique combination of genes from both parents.
In asexual reproduction, genetic material is passed down from a single parent to offspring without the involvement of gametes. This can occur through various mechanisms such as binary fission, budding, or fragmentation, depending on the organism.
How is life classified into different kingdoms and domains?
Domains : Bacteria, Archaea and Eukarya
–>
Kindgoms : Bacteria, Archaea and Eukarya [Protises (Algae and Protozoa), Fungi, Plants and Animals]
What are the main types of molecules in biology?
Carbohydrates
Proteins
Fats
Nucleic Acids
Water
What are the properties and functions of water?
Water has high heat capacity and can absorb/store significant amount of heat without large changes in temperature =buffers temperature change and thus stabilises temperature
- Good evaporative cooling : evaporation abosrbs heat and cools the body
- Freezing water releases energy and melting water absorbs it (natural buffer against rapid temperature changes = prevents rapid freezing or heating.)
* When water freezes, it expands and becomes less dense, causing ice to float on the surface (layer of ice can insulate water underneath/floating platforms)
* Water tension/capillary action/wetting vs waterproofing
* Good solvent of polar molecules
* Poor solvent of hydrophobic molecules (hydrophobic effect)
How do carbohydrates form disaccharides from monosaccharides and exmaples of sugar polymers ?
monosaccharides join together through a process called condensation or dehydration synthesis. This involves the removal of a water molecule, resulting in the formation of a glycosidic bond
examples of polymers:
Sugar polymers (long chains of
monosaccharides)
- Starch
- Chitin (structural - exoskeleton)
- Cellulose (structural - cell wall)
lipids + functions
Fats, oils, waxes, steroids/sterols
* Poorly soluble in water
* Soluble in organic (hydrophobic)
solvents.
* High proportions of C/H
- Energy stores (triaglycerols)
- Signalling molecules (steroids)
- Protection and waterproofing (waxes)
- Structure/barriers (waxes/phospholipids –
see next slide)
amino acids and role
α-Amino acids
* Building blocks of proteins
* Technically an amino acid with an amino group (-NH 2) and a carboxylic acid group (-COOH)
* But the 20 commonly occurring amino acids found in proteins and coded by our genes have the same basic alpha (α) structure
* In an aqueous solution the amino and acid groups are charged ( -NH 3+ and – COO-) – this is the normal state for amino acids in nature.
[The “alpha structure” of amino acids refers to the common structural feature shared by the 20 naturally occurring amino acids that are used as the building blocks of proteins. This common feature is the presence of an alpha (α) carbon atom, which is a carbon atom located in the center of the amino acid molecule. The alpha carbon is bonded to four different chemical groups:
An amino group (-NH2).
A carboxylic acid group (-COOH).
A hydrogen atom (H).
A side chain (R group), which varies in its composition and gives each amino acid its unique characteristics.
This alpha carbon and its four attached groups define the basic structure of amino acids. The differences in the side chains (R groups) give each amino acid its distinct properties, and these differences are essential for the diversity of amino acids and their functions in protein synthesis.]
