IB CHEM EXAM

Cohesion

Force of attraction btw the molecules of the same substance. In other words, sticks together/attracts. Ex: water molecules

Adhesion

Force of attraction btw different type of molecules/substances. In other words, stick to other surfaces.

Surface tension

the tendency of liwuid surfaces to shrink to the minimum surface area due to chesive forces. In other words, tension at the surface. Ex: paperclip at the top of the water surface.

Solvent properties

is the ability to dissolve a solute. In other words, the dissolver.

What is the medium of life?

Water is the medium of life, acting as a universal solvent fro metabolic reactions.

What are the chemical properites of water?

Cohesion, Adhesion, Surface tension, & Solvent properties (CASS).

Bouyancy

upwards force on an object in s fluid that opposes the weight (gravitational force). In other words, a force that counteracts gravity (bounce).

Viscosity

Fluid related to its resistance to flow. In other words, resistance to flow. Ex: a fluid that is resistance is syrup. 

Thermal conductivity

A substance that transfers heat energy. In other words, transfer heat energy. Ex: wet hand vs Dry hand. The wet hand wol conduct heat away from your hand, making your hand feel more colder than your dry hand. 

Specific Heat Capacity

The amount of energy required to chnage the temperature of a given amount of substance. In other words, how much energy it takes to change the temperature. Ex: water has a high specifc heat capacity & metal has a low specific heat capacity.

What are the physical properties of water?

Bouyancy, Viscosity, Thermal conductivity, & Specific Heat Capacity (BVTS).

Capillary Action

the ability of a liquid to move through narrow tubes that results from cohesion, adhesion, and surface tension. In other words, when liquid flows through narrow spaces without external forces, such as gravity. 

Electron microscopy

uses beam of electrons to detect the image.

Light microscopes

uses light to view specimens usually with a magnification of 400-1500 times. Ex: School’s old pictures. Their actual size 10-400x.

Theory of spontaneous

Now disproved theory that livin organisms could arise from non-living matter. Ex: soil, manure, and decaying process.

Cell Theory

All livings things are made of one units, cells, AKA basic units of life and that all cells arise from other cells.

Gram positive

Purple stains help make it visible. Which are peptidoglycan stains layer of Gram Positive cells but not Gram Negative.

Gram negative

Pink stains, help make the areas of the cell be visible. Peptidoglycan doesn’t stain this.

Freeze fracture microscopy

Involves freezing a sample and then using a specialized tool to break the sample into small pieces, which are then conserved using an electron microscope to examine the internal structure. 

Cryogenic electron microscopy

involves freezing a sample to cryogenic temperature (-180 & colder) to fix the molecules, making them more firm/stable. These are viewed using electron microscopy. Improves resolution of image formed and reduce damage that may occur from the electron beam.

Immunofluorecence microscopy

Used in light microscopy to better visualize certain structures. a flurescent tag (a molecule that is attached chemically to aid in the detection of a miomolcules such as, protein, antibody, or amino acid).

Fluorescent Dyes

Used in light microscopy, when dye is added to the sample it will preterentially attach to certain structures. As in ummunofluorescene, the labeled areas will appear brightly colored spots, allowing visualisation of the target molecule throughout the specimen.

Prokaryotic cell

group of organisms cells, DONT HAVE NUCLEUS & NO MEMBRANE-BOUND ORGANELLES. Diameter: 0.1 & 5.0 micrometers.

Eukaryotic cell

group of organisms cells, cells don’t TYPICALLY have NUCLEUS & MEMBRANE-BOUND ORGANELLES. Diameter: 10 & 100 micrometers.

What cell is a unicellular (made up only of 1 cell)?

Prokaryotic cell

What cell is a multicellular (made more than +1 cell)?

None, but some Eukaryotic cell are multicellular

What organelles do Prokaryotic cells contain?

Cell wall, Plasma membrane, Pytoplasm, Naked DNA, 70s ribosomes, Plasmid

What organelles do Eukaryotic cells contain?

Plasma membrane, Cytoplasm, Mitochondria, 80s ribosomes, Nucleus, SMOOTH & ROUGH endoplasmic reticulum, Golgi Apparatus, Vesicle, Vacoule, Cytoskeleton.

Heterotrophic organisms

obtain nutrients from the external environment. In other words, feeding on particles that ecnounter in their environment.

Autotrophic organisms

obtain nutrients from producing nutrients from inorganic material. In other words, manufacture their own food uisng their large chloroplast.

Animal cell Structure

contain centrioles (2 cylindrical organnles that help to establish and organise the microtubules). Lysomes (memebrane-bound bags of hydrolytic enzymes that break down & destroy biological molecules & old cellular organelles. Found in phagocytic: capable of engulfing & digesting other cells/particles.

Some Animal cells contain vacuoles, which tend to be smaller than vacuoles found in Plant cells. Animal vacuoles store water, nutrients, & waste products.

True

Plant cell structure

contain cell wall made of polysacchoride= Celluose. It resists osmotic pressure. Some contain chloroplasts (that convert light energy into chemical energy in the process of photosynthesis).

Osmotic pressure

measure of the tendency of solvent moleucles to move into a solution. The amount of pressure needed to stop the flow of solvent across a semipermeable membrane from a region of lower to hgiher solute concentration.

The vauole plant cell is much LARGER than the vacuoles found in the animal cells

TRUE

Osmotic potential 

measure of the potential of a solution to lose water through water. In other words, how much the solute concentration lowers the potential energy of water. 

Fungal cell structure 

contain cell wale made of a polysaccharide= Chitin. Contain large vacuoles- which degrade (break down) molecules in the cell & acting  as a storage site for small molecules such as ions. Contain centrioles (producing & organizing the cytoskeleton). Centrioles are NOT PRESENT in MOST FUNGI except for the MALE GAMETES. SOME fungi are UNICELLULAR & MULTICELLULAR.

Anucleate is a cell without a nucleus & Multinucleaute cell containing more then 1 nucleus.

True

Solvent 

ability to dissolve

Solute

substance that is dissolved

Covalent Bond

a chemical bond btw 2 atoms formed by sharing electrons. Ex: water molecule contains 2 hydrogen atoms, covalent bonded to 1 oxygen atoms.

Electronegative

measure of how much an atomic nucleus attracts the electorns that are involved in a chemical bond. Ex: oxygen is more electronegative than hydrogen b/c it causes shared pair of electrons to be pulled slightly closer to the oxygen atom. 

Electrostatic attraction

Force attraction btw slightly positively charged hydrogen atom & slightly positvely charged & negavtively charged . Ex: oxygen atom of another oxygen.

Hydrogen Bond

weak intermolcular force that exists when electronegativity creates a polar covalent bond. Ex: form btw water molecules due to weak electrostatic attraction.

Dipolar

molecules wit/ an area of negative charge & postive charge, due to an unequal distribution of electrons. Ex: water.

Ions

are atoms either lost.gained electrons. Positive/or Negative.

Dissolve

The process of a solute mixing wit/a a solvent to form a solution.

Hydrogen Shells

water moleucles surrounding & forming hydrogen bonds with/dissolved ions in a solution.

Dissolution

the process of solute particles moving and becoming evenly spread oput in a solvent. In other words, the seperation of solute particles & their uniform distribution throughout the solution. 

Homogenous Mixture

Formed when a solute is dissolved in a solvent. (Not visible)

Solution

A mixture formed when  solute dissolves in a solvent.

Selectively / semi- permeable memebrane

A membrane that DOES NOT ALLOW the FREE MOVEMENT of all molecules & is permeable only to certain molecules. Water can, but solutes cannot. Ex: due to size, water will move across the membrane by osmosis, until both solutions have equal solute concentrations (in a state of equilibrium—opposing forces/processes are eqaul in magnitude). In other words, water can go through, NOT the solute, allowing flow. Restricts the movement of solute.

Osmotic concentration 

a measure of solute concentration ( aka osmolarity). In other words, a total concentration of all solute particles in a solution.

Hypertonic

A solution that has a higher solute concentration than another solution. In other words, lots of solutes. Ex: Cells in this solution will shrink.

Hypotonic

a solution that has a lower solute concentration than another solution. In other words, low solutes. Ex: Cells in this solution will swell and burst.

Isotonic

has the same solute concentration as another solution. In other words, an equal solute solution. Ex: cells will remain the same.

Water alwaysd flows from Hypotonic to Hypertonic.

True

Osmosis

the movement of water molecules across a selectivley/semi- permeable memebrane from an area of lower solute concentration to a higher solute concentration. In other words, net water molcues across a semi-permeable membrane from a high to low concentration.

Diffusion

General process of particle movement from an area of higher concentration to an area of lower concentration. Not necessarily involving water or a membrane.

Osmosis is a specific type of diffusion

True

Crenated

The state of an animal cell shrivelling & shrinking as a result of water loss.

Plasmolysis

The shrinking of the cell membrane away from the cell wall in plant cells due to a loss of water from the cell. 

If an Animal cell is placed in a Hypertonic solution, where there is a higher solute concentration, there will be a net movement of water out of the cell and into the surrounding solution. This leads to the animal shrinking and becoming…

Crenated

Lysis 

An Animal cell being in a hypotonic solution may burst too much b/c of the water movement moving into the cell. 

If a Plant cell is placed in a Hypertonic solution, where there is a higher solute concentration, there will be a net movement of water out of the cell and into the surrounding solution. This leads to the Plant cell shrinking, undergoing…

Plasmolysis

If a cell is placed in a hypotonic solution, where there is a lower solute concentration, there will be a net movement of water from the solution into the cell, causing it to swell. If the cell is an animal cell it may burst if too much water moves into the cell, a process called…

Lysis

Turgid

Presence of the cell wall prevents the cell from bursting & ensures cell maintain shape. 

When a plant cell is placed in a hypotonic solution, increasing internal pressure its…

Turgor Pressure

Animals cells like being in a …….. solution

Isotonic

Plant cells like being in a………solution

Hypotonic

When an Eukaryote vacuole has swelled it will exit, like bladder.

True

Standard Deviation

a measure expressing the dispersion of data in relation to the mean.

Standard Error

a statistical measure that quatifies variability btw data sets to determine precision. 

Standard error/& deviation helps us….

Helps us estimate the reliability of our data (how spread out).

Biodiversity

or biological diversity is the variety of living organisms including plants, animlas, & microorganisms. 

What are the three levels of biodiveristy?

Genetic, species, ecosystem

Genetic diversity

The diversity seen in the genes (alleles) within a population of a species. In other words, difference within & among populations of the same species. 

Species Diversity

The number and types of organisms that existed during a specific amount of time. In other words, variety of species seen in a particular habitat. The species diversity differs according to habitat.

Ecosystem diversity

Variety in ecosystems in a given area. In other words, variety of different ecosystems on earth, such as forest, desert, coral reefs, & wet lands, and the unique ecological processes & communities within them.

Ecology

branch that aims to understand that interactions btw living organisms & their environment.

Ecosystem

a community of living organisms & its abiotic (non-living) environment.

Terrestrial ecosystem

the balance of nature is amintiend through that is hunted the interplay of various ecological roles.

Herbivores

organism obtains its nutrition by consuming plants.

What role do Herbivores play?

Play a role in shaping & controlling the vegetation within the community.

Reproductive Isolation

a mechanism that prevents individuals of different species from mating & producing viable.

Geographical Isolation

inability of organisms of the same species to successfully breed. Ex: barriers such as mountains, rivers, and etc. Which restrict gene flow btw populations. 

Behavioural Isolation

Type of reproductive isolation in which differences is BEHAVIOR, such as mating rituals or courtship displays, prevent the individuals from breeding or TEMPORAL ISOLATION. 

Temporal Isolation

individuals of the same species have different mating season/times of reproductve activity, preventing them from breeding wit/individuals from other populations

Inbreeding

breeding btw closely related individuals.

If genetic diversity is low it means the species are in…..

DANGER! The species is at rish of extinction.

Inbreeding leads to?

It leads to genetic uniformity, which is flaws disabilities become expressed or more frequently in the population.

Preserving genetic diversity, it increases….

All the above

Species richness

# of different species in the area

Species eveness

the relative abundance of different species in the given area. If the # of individuals of each species vary, the species eveness is low.

Ecosystem diversity

is the variety of ecosystems, both terrestrial (relating to land) & aquatic, found in a given geographical area. Ex: a rainforest has many ecosystems within it.

Megafauna

large animals

Invasive/alien species

away from natural habitat, invasive species have few natural predators. Arrive & multiply & affect the Native species. These are non-native and causes harm. Its invasive bc it’s not Native.

Pest

poses significant threat ro resources & HUMAN HEALTH. Ex: White--footed mouse is native b/c it causes damage and health issues. 

Habitat Fragmentation

process of breaking a large continuos habitat into smaller, isolated patches, often due to human activities (road destrcution). Division of a large continuos habitat into smaller non-contiguos areas. 

What is anthropogenic species extinction?

Human activity leads to extinction of species