BIS 10 Module 4

chemical senses

Senses that detect molecules: taste and smell.

umami

The savory taste; detects glutamate.

macronutrient

The major food categories: carbohydrates, proteins, fats.

anabolism

Building larger molecules from smaller ones; consumes energy.

catabolism

Breaking molecules down; releases energy.

cellular respiration

Aerobic breakdown of glucose in mitochondria; high ATP yield (~30 per

glucose).

fermentation

Anaerobic breakdown of glucose in the cytoplasm; low ATP yield (~2 per

glucose) but fast.

vitamin

A small organic molecule required in small amounts that the body

cannot synthesize.

water-soluble vitamins

B and C; excess excreted in urine.

fat-soluble vitamins

A, D, E, K; stored in body fat; can accumulate to toxic levels.

lactose

The sugar in milk.

lactase

The enzyme that breaks down lactose.

lactose intolerance

Inability to produce lactase as an adult; common globally.

microbiome

The community of microorganisms living in or on the body. The gut

microbiome lives mainly in the large intestine.

villi/ microvilli

Finger-like projections of the small intestine that vastly increase surface

area for absorption.

natural selection

The process by which heritable traits that improve survival become

more common in a population over generations.

selective pressure

An environmental factor (like an antibiotic) that favors organisms with

certain traits.

artificial selection

Human-driven selection (selective breeding); contrasted with natural

selection.

antibiotic

A drug that kills or inhibits bacteria, typically by targeting a feature

bacteria have that we don’t.

penicillin

The first widely used antibiotic, discovered by Fleming in 1928.

antibiotic resistance

The ability of bacteria to survive in the presence of an antibiotic.

horizontal gene transfer

Transfer of genetic material between organisms other than by parent-

to-offspring inheritance. Common in bacteria.

plasmid

A small circular DNA in bacteria, often carrying resistance genes that

can spread.

antibiotic stewardship

The deliberate effort to use antibiotics carefully to slow resistance.

GMO

Genetically modified organism — genome altered by genetic

engineering.

selective breeding

Breeding selected parents over many generations to amplify desired

traits.

Bt corn

Corn engineered with a bacterial gene that produces a protein toxic to

specific insect pests.

golden rice

Rice engineered to produce beta-carotene, a vitamin A precursor.

recombinant insulin

Insulin produced by bacteria carrying the inserted human insulin gene.

rainbow papaya

GMO papaya engineered to resist ringspot virus; saved the Hawaiian

papaya industry.

Most adult humans worldwide are lactose intolerant. The most accurate explanation is:

Most adult humans stop producing lactase. Adult lactase production (lactase persistence) is a recent human adaptation in populations with dairy farming.

Why are fats more calorie-dense than carbohydrates or proteins?

Their chemical bonds store more energy per gram when oxidized — about 9 cal/g, more than double the ~4 cal/g in carbs and proteins

Why does evolution favor having 35 different bitter taste receptors but only one sweet receptor?

Bitter often signals plant toxins, and different toxins require different receptors. Sweet signals sugar, which is chemically uniform.

Antibiotic resistance is best understood as an example of:

Natural selection; bacteria with random mutations that confer resistance survive antibiotic exposure and pass them on.

Which of the following is the BEST example of a GMO?

Corn engineered to produce a bacterial toxin (Bt) that kills specific insect pests.

A new antibiotic is developed and used widely. After several years, resistant bacteria emerge. Which type of mutation most likely caused the resistance?

A random mutation that happened to change the bacterial target enough to prevent drug binding (e.g., a missense mutation in the target protein).

a double stranded DNA sample is found to contain 33% adenine. What percentage of the sample is guanine?

17%

why dont’ mRNA vaccines permanently change your DNA?

mRNA is translated in the cytoplasm and degrades quickly

Cancer is generally driven by

multiple mutations across multiple genes leading to uncontrolled growth of cells

Why does seasonal influenza require a new vaccine every year

influenza accumulates small mutations in surface proteins, so last years vacine no longer matches as well (antigenic drift)

Antibiotic resistance is best understood as an example of

natural selection, bacteria with random mutationms that confer resistance survive antibiotic exposure and pass themj on

a breeder selects only the fastest growing fish for reproduction over many gen. aggression also increases, the best explanation is

genes affecting growth and aggression may be genetically linked

A drug causes GLUT4 transporters to remain inside cells even after insulin binds its receptor. which is a likely outcome

increased blood glucose

researchers engineer a mouse whose dopamine transporters cannot bind cocaine but otherwise function normally. compared with normal mice, cocaine administration would most likely produce

little or no increase in dopamine signaling

B cell

plasma cell, makes antibodies (B cell: antiBodies)

cystic fibrosis, a couple with no symptoms have a child with this, explanation is

both parents are heterozygous carriers but show no symptoms,

differents between type 1 and 2 diabetes

type 1 is caused by autoimmune destruction of beta cells, type 2 is caused by insulin resistance

Best example of GMO

corn engineered to produce a bacterial toxin that kills specific insect pests

a toxin prevents voltage-gated potassium channels from opening. what is immediate effect on an action potential

repolarization is delayed

Why are fats more calorie dense than carbohydrates or proteins

their chemical bonds store more more energy per gram when oxidized

cell at rest, resting potential

-70

polarization

cold, negative degrees

Types of cells brain is made up of

neurons and Glial cells

neurons

information processing electrical signaling

glial cells

support and maintenance, “glue of the brain”

ion gradients

battery that powers all neural communication

Na+/K+ pump

engine that creates and maintains neural excitability

resting potential creates

electrical foundation for action potentials

how do neurons communitcate over long distances?

electrical signals

volted gated ion channels

convert small voltage changes into large electrical signals

3 states of voltage-gated Na+ channels

closed:resting state no flow

open: depolaration opens channnel-Na goes in

Inactivated: channel closes

rapid rise

channels open

rapid fall

channels inactivate

action potential are waves

local channel activity creates long distance signal propagation

electrical signals handle

speed

chemical signals handle

precision and control

synapses transmission convert

electrical to chemical to electrical signals for precise communication

synaptic vesicles

pre-packaged chemical signals waiting for the calcium trigger

molecular mechanisms-receptors, channels, neurotransmitters

create the behaviors that make us who we are

individula neuron connect to

form circuits

individual neurons are simple but

networks of neurons can create consciousness

memory

pattern of connected neurons firing together