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biology paper 1 > cell structure and transport > Flashcards

cell structure and transport Flashcards

1
Q

how many micrometers and nano meters are within one millimeter

A

1000 micrometers = 1 millimeter
1,000,000 nanometers = 1 millimeter

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2
Q

state the advantages of using a light microscope

A

light microscopes are cheaper
they are portable allowing for easy use in labs
they can magnify object by around 2000x
they can magnify live specimens

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3
Q

state differences between an electron microscope and a light microscope

A

electron microscopes are stuck in place (cannot be moved)
electron microscopes have a magnification of around 2 million times compared to a light microscopes 2000 x
electron microscopes give a 3D image
electron microscopes are expensive and need to be kept in a certain humidity,temperature and pressure to function

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4
Q

how do you calculate magnification

A

magnification can be calculated by multiplying all of the lenses used to enhance the image for example if the eyepiece lens is 4x and the objective lens is 10x then overall magnification is 40x

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5
Q

how do you calculate the size of the object when looking at it through a microscope

A

the formula magnification = image size/size of the real object can be used to calculate the sizes of the specimen you are investigating

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6
Q

what is resolution

A

resolution is the minimum distance between two points at which they can be distinguished as separate objects

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7
Q

what is the nucleus for

A

the nucleus is used to control all the activities within the cell and holds the cells genetic information. It carries the genes and chromosomes and the information for the proteins to make new cells

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8
Q

what is the cytoplasm for

A

cytoplasm is a liquid gel in which most of the chemical reactions needed for life are contained

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9
Q

what is the cell membrane

A

the cell membrane is the lining of the cell in which the passage of substances are controlled for example glucose and mineral ions are allowed to enter the cell and urea and hormones leave the cell

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10
Q

what is mitochondria

A

mitochondria are cellular structures where aerobic respiration takes place releasing energy for the cell

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11
Q

what are ribosomes

A

ribosomes are where protein synthesis takes place making the proteins for the cell

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12
Q

name the cellular structures of an animal cell

A

. nucleus
. cell wall
. mitochondria
. ribosomes
. cytoplasm

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13
Q

what are chloroplasts

A

chloroplasts are a cellular structure in plants that undergo photosynthesis and contain the green pigment chlorophyll that makes the plant leaf green

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14
Q

what is a vacuole

A

it is a space in the cytoplasm for storing cell sap whcih is needed to keep the cells rigid in the plant

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15
Q

what is a cell wall

A

it is a wall around the cell made of cellulose keeping it rigid and supports it

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16
Q

what are eukaryotic cells

A

animal and plant cells are eukaryotic as they have a cell wall ,membrane and DNA enclosed within the nucleus

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17
Q

what are examples of prokaryotes and what is their size in comparison to eukaryotes

A

bacteria and viruses are examples of prokaryotes and are 1-2 orders of magnitude smaller (10x-100x)

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18
Q

what are slime capsules

A

slime capsules add extra protection and support to the cell.

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19
Q

what are flagellum (flagella)

A

flagella are long strands made of protein. which allow the bacteria to move

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20
Q

where is the DNA within a prokaryotic bacteria cell

A

bacteria cells have free genetic material meaning that it is not contained within a nucleus and have extra strands of DNA called plasmids which contain very specific features such as antibiotic resistance

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21
Q

what is cell specialisation

A

cell specialization is where animal or plant cells gain adaptations which help them carry out their function and this is called differentiation

22
Q

name some features of a sperm cell

A

they contain enzymes at the head of the cell allows them to digest the outer layer of the ovum, they have tails to swim and contain many enzymes to produce enough energy for the cell

23
Q

name some features of a nerve cell

A

a nerve cell’s function is to carry electrical impulses around the body and the long axon connects to different nerve cells around the body. The nerve cell contains myelin around the axon to insulate it and speed up the reaction and the end of the axon has synapses that allows it to connect to other nerve cells. The body of the cell has dendrites to increase its surface area to allow it to connect easily

24
Q

name some features of a muscle cell

A

muscle cells can contract as they contain protean fibers to change their length and the fibers shorten when the muscle cell contracts. They contain lots of mitochondria to provide energy for muscle contraction

25
Q

name some features of a root hair cell

A

they increase the surface area of the root to increase its effectiveness at absorbing water. They do not contain chloroplasts since they are underground

26
Q

what are xylem cells

A

they are long tubes found in the stem of a plant that carry water and dissolved minerals to the leaves. They have very thick wall to provide support. The cell walls are sealed with lignin which causes the xylem cells to die and have no internal structure ( chloroplasts vacuole e.c.t)

27
Q

what are phloem cell

A

they carry dissolved sugars through the plant and have no nucleus and limited cytoplasm. The end walls of the phloem cells have sieve plates which allow dissolved sugars to move through the interior of the cells. They have companion cells attached to the phloem cells by pores which have many mitochondrion to provide energy to the phloem vessel

28
Q

describe how to prepare a slide

A

• First add a drop of water to the slide to make it easier for the light to pass through and to make sure the specimen does not dry out
• Then place your specimen on the drop of water using tweezers
• add a drop of Iodine solution which is a stain. Stains are used to highlight objects in a cell by adding color
• Finally place a cover slip onto your specimen ( a thin sheet of glass) and then slowly tilt and lower it onto the specimen to ensure there is no air bubbles as they’ll obstruct your view

29
Q

how to use a microscope

A

• Place the slide onto the stage
• set it to its lowest powered objective lens (usually 4x)
• use the coarse objective lens to set the microscope so that it is just above the slide (usually has a lowest position)
•look down the eyepiece lens and bring the microscope upwards until the image is nearly in focus
• use the fine adjustment knob to get a clear image
• if you want to use a greater magnification swap to a higher power objective lens and refocus

30
Q

how do bacteria multiply

A

under ideal conditions bacteria can multiply by simple cell division (binary fission) every 20 minute and the amount of bacteria present after a given time is 2 ^ number of divisions (time in minutes/20)

31
Q

describe how to culture bacteria using agar gel and a petri dish

A

First sterilize any apparatus that will be used for culturing the bacteria such as the petri dish and agar gel
then heat the inoculating loop using a Bunsen burner to remove any unwanted bacteria from contaminating the culture
then the lid onto the petri dish and turn upside down to stop moisture from dripping onto the bacteria
Finally incubate the bacteria at 25 C to reduce the chance that harmful bacteria will grow

32
Q

what is the zone of inhibition

A

it is the area around an antibiotic that bacteria will not grow in and it is calculated by finding the area of the circle

33
Q

how many chromosomes does a body cell have

A

2 pairs of each or 4

34
Q

how does mitosis work

A

First the DNA replicates to form two more pairs of chromosomes
It then grows and copies the internal structures of the cell such as mitochondria and ribosomes
one set of chromosomes is then pulled to each end of the cell and the nucleus divides
finally the cell membrane and cytoplasm split to form two identical cells

35
Q

when is mitosis used

A

it is used for the growth and development of organisms
for healing any damage to cells (when an organism repairs itself)
during asexual reproduction

36
Q

what is a stem cell

A

a stem is an undifferentiated cell that can make cells of the same type and can differentiate into other types of cells

37
Q

where can stem cells be found in animals

A

in an animal stem cells are found in the embryo and the bone marrow

38
Q

what is differentiation

A

when a stem cell becomes specialized

39
Q

what is therapeutic cloning

A

when an embryo is produced with the same genes as the patient meaning the stem cells wont be rejected by the body of the patient

40
Q

where can stem cells be found in a plant

A

they are found in the roots and the buds of the plant and can differentiate at any point during their lifetime. This can be used to save extinction or help farmers

41
Q

what is diffusion

A

it the the spreading out of gas particles resulting in the net movement from areas of high concentration to areas of low concentration

42
Q

what factors affect diffusion

A

concentration gradient,temperature and surface area of the membrane

43
Q

what happens to the surface area to volume ratio as the organism gets larger

A

the surface area to volume ratio falls

44
Q

what is osmosis

A

osmosis is the movement of water through a partially permeable membrane from a dilute solution to a concentrated one

45
Q

what is a partially permeable membrane

A

it allows some molecules to pass through but not all

46
Q

what happens when you place a plant cell in water

A

water moves into the cell by osmosis and expands this means the plant cell has become turgid

47
Q

what happens when you place a plant cell in a concentrated solution

A

water will move out of the cell by osmosis and will shrink or become flaccid

48
Q

why do we use a cork borer when cutting the potatoes

A

it ensures that all of the potatoes are the same diameter

49
Q

what is active transport

A

when substances move from a low concentration to a higher concentration (against the concentration gradient). This process requires energy

50
Q

where is active transport found

A

it is found in the small intestine to absorb sugar molecules and in root hair cells to absorb ions from the soil

biology paper 1 (3 decks)

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