Biology Living Organisms and the Environment Practice Flashcards

This set of flashcards covers vocabulary and core concepts from the lecture notes on Living Organisms and the Environment, including cell biology, digestion, transport, homeostasis, and heredity.

Growth

A permanent increase in size usually measured in weight and height in humans.

Respiration

The breakdown of food to release energy; includes Aerobic (uses oxygen) and Anaerobic (no oxygen).

Irritability

The ability of an organism to detect and respond to stimuli in the environment.

Locomotion

The movement of the entire organism from one place to another.

Grinner (GRIMNER)

A mnemonic for the seven characteristics of living things: Nutrition, Respiration, Growth, Excretion, Movement, Reproduction and Sensitivity.

Prokaryotes

Kingdom members whose cells do not have a membrane around their nucleus nor membrane-bound organelles in their cytoplasm.

Eukaryotes

Organisms that have a 'true nucleus' meaning their cells contain a nucleus and membrane-bound organelles.

Organelle

Literally meaning 'little organ,' these are structures within cells with specific functions for proper cellular operation.

Nucleus

The cell organelle containing chromosomes made of DNA which serves as the genetic information and controls cell activities.

Mitochondrion

Commonly known as the 'power house of the cell,' it is the site of respiration and provides energy in the form of $ATP$.

Diffusion

The passive movement of particles from a region of higher concentration to lower concentration down a concentration gradient.

Osmosis

A special type of passive diffusion involving water molecules moving from higher water potential to lower water potential through a partially permeable membrane.

Active Transport

The movement of ions or molecules across a cell membrane from lower to higher concentration using energy released during respiration as $ATP$.

Turgid

A term describing a plant cell that has become full of water after its cytoplasm and vacuole grow in a hypotonic environment.

Plasmolysed

A condition where a plant cell membrane tears away from the cell wall due to extreme water loss in a hypertonic environment.

Autotrophic Nutrition

Occurs in green plants and some bacteria that use simple inorganic compounds like $CO_2$ and $H_2O$ to produce complex compounds like glucose.

Photosynthesis

The fundamental process by which green plants make their own food; summarized by $6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$.

Limiting Factor

Any factor in short or limited supply in the environment that restricts a life process such as photosynthesis.

Eutrophication

A process where leached nitrates cause algae to multiply and decay, depleting oxygen and leading to the death of aquatic animals.

Enzymes

Proteins that work as biological catalysts and remain unchanged after a reaction.

Mechanical Digestion

The physical breakdown of food into smaller pieces without chemical change, increasing the surface area for enzymes.

Peristalsis

Slow, wave-like contractions of the circular and longitudinal muscles in the alimentary canal walls that push food through the tract.

Chemical Digestion

The chemically driven breakdown of insoluble food molecules into small, soluble ones using digestive enzymes.

Chyme

The substance produced after food is mixed with gastric juices, $HCl$, and mucus in the stomach.

Absorption

The movement of digested food molecules through the wall of the intestine into the blood or lymph.

Villi

Tiny finger-shaped projections in the ileum that increase the surface area for absorption of nutrients.

Assimilation

The movement of digested food molecules into the cells of the body where they are used for energy or growth.

Deamination

The process in the liver involving the removal of the nitrogen-containing part of amino acids to form urea.

Egestion

The removal of undigested food from the body as semi-solid faeces.

Excretion

The removal from the body of waste and harmful substances produced from metabolism.

Monosaccharides

The simplest soluble and sweet carbohydrate molecules, such as glucose, containing one sugar unit.

Basal Metabolic Rate

The amount of energy used by the body at rest to maintain essential functions like breathing and heartbeats.

Kwashiorkor

A disorder caused by a lack of protein, characterized by a swollen abdomen due to water retention and a very thin appearance.

Homeostasis

The maintenance of a constant internal environment, such as regulating blood glucose or body temperature.

Negative Feedback

A control mechanism where a change from the norm triggers a response that resets the internal balance to the norm.

Diabetes Mellitus

A disease where blood glucose concentration cannot be regulated properly; includes Type 1 (juvenile-onset) and Type 2 (mature-onset).

Ultrafiltration

The process in the nephron where high pressure forces small substances from the glomerulus into the Bowman’s Capsule.

Selective Reabsorption

The process in the nephron tubules where useful substances like glucose and amino acids are taken back from the filtrate into the blood.

Neurone

A nerve cell; types include Sensory (receptors to CNS), Motor (CNS to effectors), and Relay (interconnects neurons).

Synapses

Small gaps between adjacent neurones that ensure nerve impulses travel in one direction using neurotransmitters.

Reflex Actions

Fast, automatic responses to stimuli that occur without conscious thought, such as the knee jerk reflex.

Accommodation

The process where the shape of the eye lens changes to focus on near or distant objects.

Hormones

Chemical messengers secreted by endocrine glands directly into the blood, such as Insulin and Adrenalin.

Mitosis

Nuclear cell division resulting in two identical daughter cells with the same number of chromosomes as the parent cell.

Meiosis

Reductive cell division producing four haploid daughter cells that are genetically different from each other.

DNA (Deoxyribose Nucleic Acid)

Large complex molecules that carry the unique genetic code determining the characteristics of a living thing.

Gene

A short section of DNA that serves as the basic unit of heredity and codes for a specific protein.

Allele

An alternative form of a gene located at a specific position on a specific chromosome.

Genotype

The genetic makeup of an individual for a particular characteristic.

Phenotype

The physical appearance or biochemical makeup of an individual resulting from its genotype.

Ligaments

Strong, elastic fibrous connective tissue that attaches bones together at joints to prevent dislocation.

Tendons

Tough, non-elastic fibrous connective tissue that attaches muscles to bones.

Trophic Level

The specific level at which an organism feeds within a food chain or food web.