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Biology GCSE > Cell Structure and Division > Flashcards

Cell Structure and Division Flashcards

1
Q

What are eukaryotes?

A
  • plant cells
  • animal cells
  • has cell membrane, cytoplam, nucleus
  • genetic material made of DNA
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2
Q

What subcellular structures does an animal cell have?

A
  • cell membrane = controls what goes in and out of cell, partially permeable
  • ribosome = protein synthesis
  • cytoplasm = suspends cell structures, site of cell structures
  • mitochondria = aerobic respiration
  • nucleus = controlls cell processes, DNA stored here
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3
Q

What subcellular structures does a plant cell have?

A
  • cytoplam
  • cell membrane
  • cell wall = strengthens cell, made of cellulose
  • nucleus
  • ribosome
  • mitrochondria
  • cell vacuole = filled with cell sap, stores nutrients and supports cell
  • chrloroplasts = chlorophyll, traps light energy for photosynthesis
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4
Q

What is the difference between eukaryotes and prokaryotes?

A
  • pro. = smaller than euk.
  • no nucleus
  • DNA loop floating in cytoplasm
  • may have small rings of DNA = plasmids
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5
Q

What are the levels of organisation in an organism?

A
  • cells
  • tissues
  • organs
  • organ systems
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6
Q

What adaptations does phloem cells have to perform its function?

what is its function!!!!

A
  • elongated cells to trasnport sugars over long distances
  • companion cells have many mitochondria for active transport

transport sugars made in leaves to rest of plant

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7
Q

What adaptions do xylem cells have to perform their function?

function?

A
  • hollow tubes (lumen) - no end walls to allow water and minerals flow
  • lignin in walls to provide strength and support

transports water and mineral ions throughout plant

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8
Q

What adaptations do sperm cells have to perform their function?

function!

A
  • enzymes in head to digest coating of egg
  • many mitochondria to provide energy for swimming
  • tail for swimming

carry genetic material to egg cell

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9
Q

What adaptations does a muscle cell have to perform their function?

function!!!!!

A
  • lots of mitochondria to provide energy for contraction
  • protein fibres shorten to make cells contract, shortens structure

provide movement

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10
Q

What adaptations does a nerve cell have to perform its function?

A
  • dendrites make connections with other cells
  • fatty myelin sheath speeds up impulse
  • axon = long, carries impulses across body

cary electrical impulses around body

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11
Q

Describe differentiation in animal cells throughout its life

A
  • most types of cells differentiate at early stage
  • early embryo cells = unspecialised
  • mature animals = repair of damaged tissues/ replacement of worn out cells
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12
Q

Describe differentiation in plant cells throughout its life

A
  • cells continue to divide and differentiate throughout life of plant
  • **meristems **responsible for division
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13
Q

What is magnification?

A
  • how many times bigger an image is than the object that is viewed
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14
Q

What is resolution?

A
  • measure of smallest distance between two points that still can be distinguished

poor resolution = blurred with magnified

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15
Q

How do you calculate magnification?

A

size of image/ size of real object

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16
Q

How are unwanted microoganisms kept from contaminating a culture?

A
  • sterilise petri dishes + culture media before use
  • inoculating loops passed through flame
  • lid stops microorganisms falling into agar from air (fixed in place with tape)
  • work near a flame
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17
Q

How do bacteria multiply?

A
  • binary fission
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18
Q

When were the first light microscopes developed?

A

400 years ago

19
Q

When was the electron microscope invented?

and what were they like?

A
  • 1930s
  • higher magnification
  • higher resolution
  • can see sub-cellular structures
20
Q

What kind of bacteria is used for the investigation of comparing different antibiotics or antiseptics?

A
  • bacterial lawn on agar distributed by spreader
  • agar becomes cloudy
  • no bacteria = clear agar
21
Q

How are the antiseptic or antibiotics placed in the agar?

A
  • small paper discs soaked with solutions of antibiotics/ antiseptics
22
Q

What is the clear area around the paper disc called?

A
  • zone of inhibition
23
Q

How do you compare different antibiotics or antiseptics?

A
  • measure 2 diameters of clear area
  • calculate mean (more accurate)
24
Q

Describe the cell cycle

A

1) cell growth = number of subcellular structures increase
2) DNA replicates = forms 2 identical copies of each chromosome
3) Mitosis = chromosomes separate, nucleus divides in 2
4) Cell division = cytoplasm + cell membrane divides = 2 new identical cells made

25
Q

Describe the stages of mitosis

A
  • newly replicated chromosomes joined together
  • move to centre of cell
  • chromosomes pulled apart, moved to opposite ends (poles) of the cell
  • nucleus divides
26
Q

What is mitosis used for?

A
  • growth
  • repair of worn out or damaged cells
27
Q

What are stem cells?

A
  • undifferentiated cells that divide to make new cells
28
Q

What do cells in an early embryo do and how do scientists use them?

A
  • unspecialised
  • differentiates to produce all types of cell needed to make adult organism
  • clone cells from early human embryos in lab
  • made to differentiate into different types of cells
29
Q

What are stem cells in adult animals used for?

A
  • can only produce limited range of cell types
  • replace worn out or damaged cells

bone marrow = exception, can product many types of cells

30
Q

Describe the process of therapeutic cloning

A
  • egg cell nucleus replaced with patient’s nucleus from cell
  • embryo made that has same genes as patient
  • stem cells removed to treat patient
  • not rejected, since it has same genes as patient
31
Q

What are the advantages of therapeutic cloning?

A
  • may treat diseases and replace faulty organs
  • wider range of cells produced than adult stem cells
  • stem cells not rejected by patient
  • many cells produced, some used in research
32
Q

What are the disadvantages of therapeutic cloning?

A
  • stem cells may transfer viral infection
  • ethical or religious objections (kills embryo?)
  • human eggs in short supply, collecting = risks
  • side effects of stem cells not known
33
Q

What are the benefits of growing plants from stem cells?

A
  • large numbers of new plants produced quickly + cheaply
  • rare species cloned prevent extinction
  • crop plants with useful features (eg disease resistance) -> cloned = large number of useful plants for farmer
34
Q

What is diffusion?

A
  • net movement from an area of higher concentration to lower concentration
35
Q

What affects the rate of diffusion?

A
  • concentration gradient = increases chance of particles moving from high concentration to low concentration
  • temperature = increases kinetic energy of particles, moves faster
  • surface area = more membrane for particles to move across
36
Q

How is the small intestine adapted for efficient diffusion?

A
  • vili and microvili increase SA
  • wall of vili = thin
  • good blood supply
37
Q

What are the lungs adapted to increase the rate of diffusion?

A
  • alveoli increase SA
  • thin walls
  • surrounded by capillaries
  • good ventilation (conc. grad.)
38
Q

What is osmosis?

A
  • diffusion of water from dilute solution to more concentrated solution through a partially permeable membrane
39
Q

How are fish gills adapted to increase diffusion?

A
  • gill filaments increase SA
  • filaments well supplied with blood
  • thin walls reduce diffusion pathway
  • good ventilation
40
Q

How are roots and leaves of plants adapted for efficient diffusion?

A
  • extension of root hair cells = high SA
  • large internal surface area for diffusion
  • thin = reduces diffusion distance
41
Q

What is active transport?

A
  • moving substances from dilute solution to more concentrated solution

requires energy from respiration

42
Q

What is active transport used for in plants?

A
  • mineral ions from soil to root hair cells
43
Q

What is active transport used for in animals?

A
  • absorbing sugar in small intestine

Biology GCSE (13 decks)

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