BIOLOGY REVISION

there are two types of cells, eukaryotic and prokaryotic. Prokaryotic cells...

There are many different organelles in animal and plant cells: the [blank_start]mitochondria[blank_end] is where respiration takes place. the nucleus contains [blank_start]genetic information/DNA[blank_end] and controls what the cell does. the ribosomes occur in great numbers in the cell cytoplasm either freely, in small clusters, and function as the site of [blank_start]protein[blank_end] manufacture. the cytoplasm is a jelly like substance that contains [blank_start]enzymes[blank_end] and is where the [blank_start]chemical reactions[blank_end] take place. the cell wall supports, and strengthens the cell and contains cellulose the vacuole contains [blank_start]cell sap[blank_end] and has what the cell needs to survive. chloroplasts contain [blank_start]chlorophyll,[blank_end] which is what makes them [blank_start]green.[blank_end] this is where the process of [blank_start]photosynthesis[blank_end] takes place.

true or false: A Plant cell has exactly the same things as an animal cell, no more and no less.

label this diagram of a bacterial cell.

a head of a pin is roughly 1 mm in diameter,a prokaryotic cell is 1 micrometer. how many cells can fit across the head of the pin?

light microscopes use [blank_start]light[blank_end] and [blank_start]lenses[blank_end] to form an image of an object and [blank_start]magnify[blank_end] it electron microscopes use [blank_start]electrons[blank_end] - they pass [blank_start]electrons[blank_end] through the object and magnify it. electron microscopes have a higher [blank_start]resolution.[blank_end] [blank_start]resolution[blank_end] is the ability to distinguish between two points. a higher [blank_start]resolution[blank_end] = a [blank_start]sharper[blank_end] image

what is the correct formula for magnification?

a student wants to use a light microscope to view a sample of onion cells. the student adds a drop of iodine to her sample. which statement best describes when a stain might be used to view a sample of tissue?

label the parts of the microscope.

a specimen is 50 micrometers wide. calculate the width when it is magnified 100X in mm

how do the magnification and resolution compare between the two types of microscope?

label this image: show how the specified feature allows the cell to be adapted to its job.

the sperm cell has a streamlined [blank_start]head,[blank_end] which helps it move faster, and it contains many [blank_start]enzymes.[blank_end] It has lots of mitochondria, and a long tail to help it [blank_start]swim.[blank_end]

define cell differentiation. choose the most appropriate sentence.

*for this question, YOU MUST write the exact definition for the word otherwise you're wrong according to this quiz* define diffusion diffusion is the [blank_start]spreading out[blank_end] of particles from an area of [blank_start]high concentration[blank_end] to an area of [blank_start]low concentration[blank_end]

chromosomes are made from [blank_start]genetic information[blank_end]/DNA. they are found [blank_start]inside[blank_end] the [blank_start]nucleus[blank_end]

plant cells never lose their ability to differentiate throughout their lifetime. This is not true for animal cells.

most [blank_start]differentiation[blank_end] happens when an organism [blank_start]develops[blank_end]. in most [blank_start]animal[blank_end] cells, when they have specialised, they [blank_start]lose[blank_end] the ability to differentiate. an eye cell can differentiate into a skin cell. the statement above is [blank_start]false.[blank_end]

you need to know these examples of specialised cells. sperm cells are specialised for [blank_start]reproduction[blank_end] [blank_start]nerve[blank_end] cells are specialised for rapid signalling muscle cells are specialised for [blank_start]contraction[blank_end] [blank_start]root hair cells[blank_end] are specialised for absorbing water and [blank_start]minerals[blank_end] [blank_start]pholem[blank_end] and [blank_start]xylem[blank_end] cells are specialised for transporting substances

[blank_start]starch[blank_end] and [blank_start]proteins[blank_end] are too big to pass through a partially [blank_start]permeable[blank_end] membrane.

diffusion rate is affected by three things. 1) the [blank_start]concentration gradient.[blank_end] the bigger it is, the faster the rate of diffusion 2) the surface area. the bigger it is, the [blank_start]faster[blank_end] the rate of diffusion 3) temperature. the higher it is, the more [blank_start]energy[blank_end] the particle has.

a student says, "if i was to drop a droplet of ink into water, osmosis would take place, causing all of the water to eventually turn the colour of the ink. This is true as osmosis is the movement of water particles." is this true

[blank_start]Osmosis[blank_end] is the movement of water from a [blank_start]high[blank_end] water concentration to a [blank_start]low[blank_end] water concentration through a [blank_start]partially[blank_end] [blank_start]permeable[blank_end] membrane. Osmosis takes place in all living cells.

osmosis is a special type of diffusion

the definition of precision is "how close you are to the true value". it is the same thing as accuracy. is this true or false? if so, why or why not?

The potato experiment: this experiment involves cutting up a potato and leaving it in differently [blank_start]concentrated[blank_end] solutions of [blank_start]water[blank_end] and [blank_start]sugar[blank_end]. It shows the effects of [blank_start]osmosis[blank_end] - if the potato wedges have [blank_start]increased[blank_end] in mass it means that water has been absorbed by the potato by osmosis. if water has been drawn out, they will have [blank_start]decreased[blank_end] in mass. you then plot the figures on to a [blank_start]graph.[blank_end] the dependant variable is the [blank_start]chip mass[blank_end] and the independent variable the [blank_start]concentration[blank_end] of the solution.

active transport is..

we need active transport in our bodies. Plants use this as well. if this statement is true, give examples for each.

inside the nucleus, there are [blank_start]chromosomes.[blank_end] [blank_start]23[blank_end] pairs of chromosomes from the mother, and [blank_start]23[blank_end] from the [blank_start]father[blank_end], adding up to a total of [blank_start]46.[blank_end] the [blank_start]cell cycle[blank_end] tells us how we make new cells. when the parent cell splits, it makes two [blank_start]daughter[blank_end] cells. the cycle has two stages, [blank_start]mitosis[blank_end] being stage two. the cell cycle makes new cells for [blank_start]growth[blank_end] [blank_start]development[blank_end] and [blank_start]repair[blank_end] the [blank_start]chemical[blank_end] molecule that chromosomes are made of is called [blank_start]GENES[blank_end]

the daughter cells are genetically identical.

these are the [blank_start]two[blank_end] stages of the cell cycle. stage 1: DNA is spread out in long [blank_start]strings.[blank_end] before it divides, it [blank_start]increases[blank_end] the amount of sub cellular structures, such as [blank_start]mitochondria[blank_end] and ribosomes. it then [blank_start]duplicates[blank_end] its DNA which is copied and forms [blank_start]"X"[blank_end] shaped chromosomes. stage two: [blank_start]mitosis[blank_end]. the chromosomes line up at the [blank_start]centre[blank_end] of the cell, and cell fibres pull them apart. the two arms of the chromosome is put on either side of the cell membranes form around each set of chromosomes. these become the [blank_start]nuclei[blank_end] of the new cells - the nucleus has divided. lastly, the [blank_start]cytoplasm[blank_end] and [blank_start]cell membrane[blank_end] divide. the cell has now produced two daughter cells.

the DNA of a daughter cell is not identical

this is the process of the cell cycle. drag and drop these labels to the appropriate spaces.

a person with the disease "[blank_start]emphysema[blank_end]" may experience lower [blank_start]energy levels[blank_end] while doing physical exercise. This disease affects the [blank_start]alveoli[blank_end], damaging the walls. the reason for this symptom is since the walls of the alveoli, there will be a [blank_start]lower[blank_end] surface area. a [blank_start]lower[blank_end] surface area leads to a lower rate of [blank_start]diffusion[blank_end] of oxygen. the lower the rate of [blank_start]diffusion,[blank_end] the less [blank_start]respiration[blank_end]. respiration is what gives us [blank_start]energy[blank_end] therefore the person will experience lower [blank_start]energy[blank_end] [blank_start]levels[blank_end].

here are some adaptations to make gas exchange easier. 1) [blank_start]Thin membrane[blank_end]: this allows only a short distance to be needed for diffusion to take place. 2) [blank_start]large surface area[blank_end]: so a lot can diffuse at once. 3) [blank_start]lots of blood vessels[blank_end]: good blood supply can get in and out quickly 4) [blank_start]moist lining[blank_end] : for dissolving gasses 5) [blank_start]stomata[blank_end]: tiny holes in the leaf. they have cells around them called guard cells which control the size of the stomata and prevent wilting.

the job of the lungs is transfer oxygen to the blood and remove waste CO2 from it. where in the lungs does gas exchange take place?

the [blank_start]small intestine[blank_end] is covered in small [blank_start]villi[blank_end] which increase [blank_start]surface area[blank_end] to that digested food is absorbed efficiently into the [blank_start]blood[blank_end]. they have a [blank_start]single[blank_end] layer of surface cells and a very good [blank_start]blood[blank_end] supply to assist quick absorbtion

the top of the leaf is the exchange surface as sunlight helps with the process. suggest why this may be true/false.

LEAVES: carbon dioxide diffuses into the [blank_start]air spaces[blank_end] in the leaf, then to the cells where [blank_start]photosynthesis[blank_end] happens. the leaf's structure is adapted so that this can happen easily: 1) the [blank_start]underneath[blank_end] of the leaf is the gas exchange surface and is covered in [blank_start]stomata[blank_end] 2) the size of stomata are controlled by [blank_start]guard cells.[blank_end] 3) the [blank_start]flattened shaped[blank_end] increases surface area the walls of the cells inside the leaf form another [blank_start]exchange surface[blank_end] of which air spaces to increase [blank_start]surface area[blank_end] REMEMBER! PLANT CELLS need [blank_start]CARBON DIOXIDE[blank_end] and take out [blank_start]OXYGEN[blank_end]

FISH: the gills are the [blank_start]gas exchange surface[blank_end] in fish. water ---> into the [blank_start]mouth[blank_end] of fish----> passes through gills water contains [blank_start]oxygen[blank_end], and the water passes through the blood in the gill, and [blank_start]CO2[blank_end] into the water.