Bio Exam Flashcards
what happens during metaphase?
chromosomes align at the equator of the cell
spindle fibres attach to centromeres
what happens during telophase?
genetic material is separated
the nuclear membrane is reformed
what happens during prophase?
centrioles migrate to opposite poles
what happens during anaphase
sister chromatids are drawn to opposite poles
processes that occur in humans which involve mitosis? (2)
growth
repair
structures in chromosome during early prophase? (2)
centromere
daughter chromosomes
stage in mitosis where chromosome is broken?
anaphase
functions of centromeres?
in metaphase they align along equator and in anaphase, they split and chromatids are drawn to poles
differences between binary fission and mitosis?
moving of chromosomes is different
(pro-cell membrane, euk-spindle fibres)
mitosis is broken down into stages
binary fission is quicker (don’t have to move as much stuff)
function of mitochondria
produces energy (ATP)
function of chloroplasts
sight of photosynthesis
why plant cells loose water when placed in a 10% salt solution? (3)
osmosis
concentration gradient
cell membrane moved away from wall
characteristics of daughter cells formed by mitosis?
genetically identical
what is osmosis?
refers to the movement of water molecules from a region of high concentration to low concentration through a semi-permeable membrane
eukaryotic cells possess both… (membranes)?
a cell membrane and nuclear membrane
similarities between lactic acid fermentation (anaerobic respiration) and alcoholic fermentation?
do not require oxygen
where do small molecules move?
passively between the phospholipid molecules (in cell membrane)
cellular structures that plant and animal cells have in common? (3)
mitochondria
lysosomes
golgi body
difference between smooth er and rough er?
presence of ribosomes on rough er but not smooth er.
how can a prokaryotic cell be identified?
absence of nucleus
what is facilitated diffusion?
the transport of small sugar molecules through the cell membrane.
mitotic cell division results in daughter cells with…?
identical genotypes and same number of chromosomes as the parent cell.
which stage of mitosis are the sister chromatids separated?
anaphase
chloride ions are transported across the membrane through carrier protein by…?
active transport
difference between plant and animal cell?
Plant cells have a cell wall, but animal cells do not. Cell walls provide support and give shape to plants. Plant cells have chloroplasts, but animal cells do not. Chloroplasts enable plants to perform photosynthesis to make food.
cells reproduce for growth and repair. compare the genetic content of the daughter cells produced in mitosis to the parent cell?
same number of chromosomes
before mitosis it doubles the genetic material
mitosis stages order
prophase, metaphase, anaphase, telophase
refer to fluid mosaic model, structure of cell membrane?
cell membrane controls what goes in and out of cell through protein channel.
proteins are embedded and are mosaic because there are so many different types.
process of exocytosis?
movement of material from low to high concentration
vesicle move to membrane and join (allows movement through membrane)
(vesicle are made up of lipids)
equation for photosynthesis?
sunlight
C6H12O6 + CO2 ——————-> H2O + O2
chlorophyll
Glucose + carbon dioxide –> water + oxygen
various types of organisms that live in the same suburban backyard. these organisms together make up…?
a community
Biotic factors are the living components of an ecosystem. They are sorted into three groups:…?
producers or autotrophs
consumers or heterotrophs
decomposers or detritivores.
a location where primary succession cannot occur?
a forest that has been destroyed by fire
homo erectus and homo sapiens belong to the…?
same genus but different species
genetic diversity is important as it ensures that a species can…? (3)
avoid inbreeding with members of the same species
resist disease
survive when the conditions of its environment are changed
adaptions? (3)
behavioural
structural
physiological
natural source of carbon dioxide emissions? (2)
plant/animal respiration
volcanic combustion
consequence of increasing carbon dioxide concentrations in the atmosphere?
enhanced green house effect
difference between habitat destruction and habitat fragmentation?
habitat destruction is the complete removal and deconstruction of the habitat/ecosystem that organisms occupy. habitat fragmentation is when the natural ecosystem is broken up into isolated patches.
why polar bear is keystone species?
it applies to the control of the population of (seals, whales, walrus, reindeer, rodents, seabirds, fish, and vegetation) in its ecosystem.
this prevents those population sizes from increasing to unsustainable levels which could disrupt the food web.
community?
the populations of different species interacting in the same place at the same time.
food chain example?
plant —> insect —> mouse —> owl
how can re-establishment of climax community occur after a fire?
climax community= An ecological community in which populations of plants or animals remain stable and exist in balance with each other and their environment.
there is existing soil after disturbance, colonising plant species can quickly grow.
which will be faster?
establishment of community on bare rock or re-establishment of habitat after logging.
re-establishment after logging.
because there is existing soil, there is rapid plant growth. the bare rock has no soil and this requires species like moss to form soil over many years.
trophic level of ecosystem is removed? what is this called?
trophic cascade
what type of species can sea otter, polar bear and elephants be defined as?
keystone species
consequences of ecosystem without sea otters? (keystone species)
the sea urchin population will increase. there is increased predation of kelp (producers) to the point where it is completely removed from the ecosystem. this results in the collapse of other trophic levels and chains that rely on kelp for energy production.
define structural adaption?
physical characteristics that an organism possesses which increase its chance of survival and reproduction.
define behavioural adaptions?
behaviours exhibited by an organism that increases its chance of survival and reproduction.
define physiological adaptions?
metabolic processes that an organism possesses which increase its chance of survival and reproduction.
needs fulfilled by adaptions that enable an animal to survive in its environment? (3)
hair in ears and eyelashes - prevent debris from getting into ears and eyes.
wings - to fly
hormone & electrochemical signals to generate the desired response
when does osmosis occur more rapidly?
when the difference in the water concentration between two areas is greater.
internal membranes in eukaryotes or prokaryotes?
eukaryotes (eukaryotic cells)
DNA replication must occur after what stage? why?
metaphase, so thgat the daughter cells produced by binary fission are genetically identical to eachother.
when an animal cell is placed in distilled water what happens to the cell?
it increases in size because water osmoses into the cell
which organelle converts sunlight energy into chemical energy?
chloroplasts
in chloroplasts, chlorophyll is the pigment that absorbs the sunlight
golgi body?
package proteins for export
ATP is used for what?
ATP is the main molecule used to store and transfer energy within the cell.
where is chemical energy in ATP stored?
mainly between the 2nd and 3rd phosphate molecules
the cell membrane structure?
a phospholipid bi-layer with proteins embedded in the layer
active transport?
molecules move from a low to a high concentration of the substance with the use of energy (ATP)
bulk transport of substances across a cell membrane is called?
exocytosis and endocytosis
in exocytosis?
the cell membrane and the vacuole fuse to enable the contents to be released outside the cell.
in endocytosis?
the cell membrane folds inwards to create a vacuole containing the substance being transported
ways substances can enter a cell across the cell membrane
diffusion
osmosis
active transport
where on a graph is the independent variable (line)
horizontal line
where on a graph is the dependent variable (line)
vertical line
before energy can be put into the ATP molecule, it must first be put into a molecule called…?
glucose
cellular respiration?
it is not breathing, it is where cells release energy from glucose.
Surface area to volume ratio?
an object’s surface area divided by its volume. It gives the proportion of surface area per unit volume of the object
how do chromosomes change during mitosis?
the microtubules attach to the chromosomes, which have already duplicated their DNA and aligned across the equator.
The spindle fibres then shorten and move toward the poles of the cell.
As they move, they pull the one copy of each chromosome with them to opposite poles of the cell.
Niches Overlap (graphs)?
Overlap occurs when two species compete for the same resource. This is referred to as interspecific competition.
high species richness?
high species richness means many different types of existing species.
can high species richness be stable community?
there is a high number of species that respond differently to the environmental fluctuations,
so the decline of one of them could be compensated by the strengthening of another one
decomposers?
feeds on and breaks down dead plant or animal matter, making organic nutrients available to the ecosystem.
An organism, often a bacteria, fungus, or invertebrate.
Aerobic respiration
(mitochondria) with oxygen
Glucose + Oxygen —–> carbon dioxide + water + ATP
C6H12O6 + O2 —–> CO2 + H2O + Energy (ATP)
Anaerobic respiration in plants
(cytoplasm) NO OXYGEN
Glucose —> Ethanol + carbon dioxide
C6H12O6 —> 2C2OH + CO2
Anaerobic respiration in animals
glucose —-> lactic acid + ATP
C6H12O6 —-> 2C3H6O3 + 2ATP (Energy)
The difference between Unicellular and Multicellular
Unicellular- consists of only one cell
Multicellular- consists of more than one cell. These cells do not all have the same structure and function.
Mrs Gren
Movement- all living organisms are capable of movement
Respiration- all living organisms require a constant supply of energy
Sensitivity- all living organisms respond to stimuli in their environment
Growth- all living organisms are capable of growth
Reproduction- all living organisms are capable of reproduction
Excretion- all living organisms must remove waste products that are produced during respiration and other cellular processes.
Nutrition- living organisms obtain nutrients from their environment
how to identify non-living organisms
an organism is only considered alive if it exhibits all seven processes (Mrs gren).
2 types of cells
prokaryote
eukaryote
cell sizes
prokaryotes- 1-10 microns
eukaryotes- 10-100 microns
what do all cells require
inputs of energy (plants need light, we need nutrients(food)
inputs of useful substances (nutrients like glucose or oxygen)
removal of wastes (gases like carbon dioxide)
what is classification
the process of sorting a variety of different things into manageable groups.
Artificial Classification
sorts organisms into groups based on similar identifiable characteristics.
Dichotomous Keys:
Keys are used in biology to categorise and identify organisms.
Natural Classification
organises species into groups that share characteristics that have been inherited from a common ancestor
(called homologous characteristics)
Hierarchical Classification:
Organisms are grouped into hierarchical categories;
Do - Domain Kids - Kingdom Prefer - Phylum Candy - Class Over - Order Fried - Family Green - Genus Spinach - Species
Adaptations
a characteristic or feature of an organism that will help to survive in its particular environment.
Organisms have general adaptations that allow them to survive and function.
Define an Ecosystem
defined by their biotic and abiotic components and the interactions between elements of these components.
zonation
a spatial change in the distribution of species.
Stratification:
term used to describe the composition and arrangement of the vertical layers (strata) of a community. (tree heights)
What is a Niche?
The way a population of organisms functions in an ecosystem is called its ecological niche.
Human Impacts on Ecosystems:
Activities such as: agriculture, forestry, fishing, urbanisation and manufacturing all have an effect on the biodiversity of ecosystems.
Key threats to ecosystem and species diversity as a result of human activities include:
Habitat fragmentation
Climate change
Introduced species/pathogens
Agriculture (cropping and grazing)
Habitat Fragmentation:
Habitat fragmentation occurs when natural forests are broken up into smaller, isolated patches due to habitat destruction.
Transforming Energy:
Producers trap the energy from external sources (e.g. the sun) and transform it into chemical energy during either photosynthesis or chemosynthesis to create organic molecules.
Transferring Energy:
The chemical energy stored within the producers can then be transferred to other organisms within the ecosystem.
the Water Cycle:
The water cycle shows the continuous movement of water within the Earth and atmosphere. It is a complex system that includes many different processes. Liquid water evaporates into water vapour, condenses to form clouds, and precipitates back to earth in the form of rain and snow.
The Carbon Cycle:
The carbon cycle is nature’s way of reusing carbon atoms, which travel from atmosphere into organisms and then back into atmosphere over and over again.
Most carbon is stored in rocks and sediments, while the rest is stored in the ocean, atmosphere, and living organisms.
the Nitrogen Cycle:
a biogeochemical process through which nitrogen is converted into many forms,
consecutively passing from atmosphere to soil to organism and back into the atmosphere.
It involves several processes such as nitrogen fixation, nitrification, denitrification, decay and putrefaction.
The Phosphorus Cycle:
Phosphorus moves in a cycle through rocks, water, soil and sediments and organisms.
Over time, rain and weathering cause rocks to release phosphate ions and other minerals. This inorganic phosphate is then distributed in soils and water. Plants take up inorganic phosphate from the soil.
Ecological Succession:
Ecological succession is the term used to describe the changes that take place within an ecosystem over time.
Primary Succession:
unidirectional process through which a lifeless ecosystem turns into a stable community of living species.
Secondary Succession:
occurs to re-establish stable communities after such events which change the vegetation and animal life in the area.
Evidence that suggests that eukaryotic cells evolved from prokaryotic cells
Both organelles have bacterial-shaped chromosomes.
Organisms that photosynthesise to create organic compounds are called
producers or autotrophs
The theory of Natural Selection needs
some organisms to survive and pass on their characteristics to their offspring
Equation 1: 6CO2 + 6H2O —–> C6H12O6 + 6O2
what is it and what does it occur in?
is Photosynthesis
occurs in Chloroplasts
Equation 2: C6H12O6 + 6O2 —–> 6CO2 + 6H2O
what is it and what does it occur in?
is Aerobic Respiration
occurs in Mitochondria
Increasing the number of samples in an experiment will reduce
the effects of random errors and increase the reliability of the data.
what has circular chromosomes
Prokaryotic cells
State the relationship between size of cubes and the SA:Vol ratio
as the cubes get smaller the SA:Vol ratio gets larger
State the significance of SA:Vol to microscopic cells
microscopic cells have a large SA:Vol that allows rapid and efficient diffusion of substances
Water Holding Frogs possess many adaptations that enable them to survive in their arid environment. Explain how their surface area to volume ratio helps them to limit water loss
bloated frogs have a small SA:Vol that enables them to conserve water by preventing water loss through their skin.
species
individuals able to interbreed to produce fertile offspring
