Biology unit 3

Catabolic processes

Cellular processes breakdown molecules to use energy

Anabolic processes

Cellular processes build molecules to store energy

Eukaryotes

A cell with a defined cell membrane bound nucleus -generally larger and more complex

Prokaryotes

a single-celled organism that lacks a membrane-bound nucleus and other internal membrane-bound organelles.

Chemoheterotrophs

organisms that get both their energy and their carbon by consuming preformed organic molecules

Eukaryotes cellular respiration

Relies on oxygen and takes place in the mitrocondria

Homeostasis

maintaining the internal conditions necessary for continued life function. All organisms maintain homeostasis. It’s a complex coordinated effort in multicellular creatures.

Dna

Dna provides a template for cellular processes

mRNA

transports the code to produce proteins

What do proteins do?

start, stop, and speed-up metabolic
processes

provide structure for organisms

facilitate exchange and transport

defend the organism

allow signaling

coordinate responses

facilitate reproduction

Nutritional Modes

how organisms obtain vital energy to fuel cellular processes and carbon to build organic molecules

Metabolism

reactions that change the form of energy and reactions that build or breakdown carbon-based molecules

How does size affect absorption and distance molecules travel?

Smaller molecules are absorb much more efficiently and diffuse significantly faster and further while larger molecules absorb slower and diffuse slower.

Aerobic respiration (type of cellular respiration)

Relies on oxygen and takes place in the mitochondria. It’s the primary mechanism of energy production and storage.

What kind of respiration can animals do when depleted of oxygen?

Anaerobic fermentation- a process that relies strictly on Glycolysis to break down glucose into pyruvate

What is the rule for Mass specific metabolic rates?

Mass-specific metabolic rate decreases with larger animals, as they’re typically more efficient than smaller ones per mass.

aerobic vs anaerobic metabolism

aerobic- oxygen dependent, high efficiency

anaerobic- Generates energy in the cytoplasm without needing oxygen, low efficency

Thermoregulation

How well an animal can regulate heat. Consists of Ectothermic and Endothermic. Influences metabolic rate, dietary requirements, and activity level.

Ectothermic

Rely on external sources like sunlight or warm surfaces to regulate their body temperature rather than generating heat from inside their bodies. Ex: Reptiles/Fish

Endothermic

Can generate their own internal body heat through a high metabolic rate to maintain a steady body temperature. Ex: Mammals

Negative feedback loop

A self-correcting process where a system responds to a change by doing the opposite to bring things back to normal or to a steady balance

What makes up a negative feedback loop?

Stimulus- A change or event that disrupts the system

Receptor- A detector that notices the change

Control center- The decision-maker that evaluates the data against a normal range

Effector- The part that acts to fix the change

Feedback- Once the effector fixes the imbalance, the original stimulus shuts off or scales back

Endocrine system

A network of ductless glands and organs that create and release hormones directly into your bloodstream. Uses chemical signaling over a long distance for a long duration and is slow acting.

Nervous system

your body's master command and communication network. Made of electrical and chemical signaling, travels a short distance for a short duration and is fact acting. Made up of neurons

Hormones

Chemical messengers produced by endocrine glands in the body. A hormone can only influence those cell types that express the receptor for that hormone. Can be exploited in form of pheromones used by humans

Different types of hormones

Peptide/Amine - Hydrophilic - binds via cell surface receptor - fast acting Ex: insulin

Steroid - Hydrophobic - binds inside cell - slower/longer lasting Ex: Testosterone

Short distance transport vs Bulk flow

Short distance transport - consists of diffusion, active transport, and facilitated diffusion. EX: digesting nutrients from food

Bulk Flow - Moving fluids through specialized channels, often through pressure differences EX: Cardiovascular system of vertebrates

What do insects use for respiration?

Insect tracheal systems—a network of tubes (spiracle → trachea → tracheoles) that deliver oxygen directly to tissues.

Open circulatory system

Usually within insect, it has lower pressure, provides less energy for bulk flow, has a limited possible size, no gases are exchanged in this system, and it is a mixing of body and circulatory systems.

Closed circulatory system

Has higher pressure, separation of fluids, more energy for bulk flow, larger possible size, and gases are exchanged using this system

Osmosis

Net movement of water across a permeable membrane, diffusion but for water.

Hypotonic vs Hypertonic

Hypotonic- less solute

Hypertoinc - more solute

Osmoregulators

organisms that must maintain internal solute concentrations that differ from those of their environment.

What happens to a MARINE fish?

Marine fish are in a very dehydrating environment, constantly losing water by osmosis. So they drink large amounts of seawater and produce very little concentrated urine.

What happens to Freshwater fish?

They gain their water through osmosis and produce large amounts of dilute urine

How do plants avoid being eaten?

They use mechanical, chemical, and mutualistic defenses to avoid being eaten

Life cycle diagrams

Life cycle diagrams portray different
stages of an organism’s life.

meiosis

Production of gametes (sperm and egg) for sexual reproduction and produces 4 cells

mitosis

cloning of parent cell and produces 2 cells

Haploid

having a single set of unpaired chromosomes in a cell

Diploid

A cell that contains two complete sets of chromosomes

Single cell eukaryotes

spend more time as haploids. Example: Green algae: Usually asexual reproduction, switches to sexual when starved

Multicellular eukaryotes

mostly dominant diploid stage with haploid gametes
produced by meiosis; mainly sexual reproduction

The Gametophyte

the haploid multicellular life stage

The Sporophyte

the diploid multicellular life stage

Benefits of asexual and sexual reproduction

Asexual reproduction- higher resource availability, less costly

Sexual reproduction- more costly but provides diversity

heterotroph vs autotroph

Heterotroph - consumes other organisms

Autotroph - creates own energy (via sun usually)

photoheterotroph

an organism that uses light for energy but must get its carbon from organic compounds (EX- Green non-sulfur bacteria)

Chemoheterotroph

an organism that uses light for energy but must get its carbon from organic compounds EX- Sulfur-oxidizing bacteria

surface area to volume ratio

smaller cells will have a higher surface area to volume ratio. Cells can squish themselves to increase their surface area to volume ratio, or have things like folds to increase it as well.

Countercurrent exchange

a physical and biological mechanism where two fluids, gases, or heat sources flow in opposite directions next to each other, allowing for the maximum transfer of a property

Complete protein

a food source that contains adequate amounts of all nine essential amino acids that the human body cannot produce on its own

What’s the difference between vitamins and minerals?

Vitamins are organic and minerals are inorganic

Surface area to volume formula