Topic 2 - Cells and Control Flashcards

1
Q

List the order of the cell cycle

A
  • Interphase - DNA spread out into strings and is duplicated
  • Prophase - Chromosomes condense (small and fatter) and nucleus breaks down to lie free in cytoplasm-
  • Metaphase - Chromosomes line up in centre
  • Anaphase - Cell fibres pull chromosomes apart to opposite sides
  • Telephase - Membrane forms around new cells and has divided
  • Cytokinesis - The dividing of cytoplasm and cell membrane
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2
Q

Why is mitosis important for organisms?

A

It replaces old or damaged cells

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3
Q

How does it create genetically identical cells?

A

The daughter cells contain exactly same sets of chromosomes so they are genetically identical diploid cells

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4
Q

Why do organisms rely on asexual reproduction?

A
  • Lots of offspring quickly and only 1 parent needed
  • Divide by mitosis (identical)
  • Can reproduce when condition perfect (aphids in sumer)
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5
Q

How does cancer form/occur?

A

Uncontrolled cell division by genes in the DNA. If a change in genes occurs causing a mutation, that cell starts dividing uncontrollably. Forms a mass of abnormal cells called a tumour. Cancer then damages tissues.

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6
Q

Define what growth in animals entails

A

All growth in animals is through cell division/mitosis. An animal gets bigger as its number of cells increases.

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7
Q

Give examples of animal cells which are specialised

A

Ciliated epitherial cells, red bllod cells (bioconcave dish)

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8
Q

Why is cell differentiation important to develop specialised cells?

A

Cell differentiation is where a cell becomes specialised for its role so an organism can work more efficiently

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9
Q

How does growth happen in plants?

A

Through cell elongation for height of a plant and cell division in the tips of roots and shoots (meristem). Meristems divide by mitosis and produce unspecialised cells that differentiate to any type of cell.

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10
Q

Examples of specialised plant cells?

A

Root hair cells
Phloem
Xylem

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11
Q

How are phloem and xylem tubes adapted?

A

Phloem - Collumned? of elongated living cells with pores at ends to let food substances through due to active transport. Translocation requires energy from respiration
Xylem - dead cells joined together in tube strengthened with lignin carry water and mineral ions from roots up

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12
Q

Where are stem cells found?

A

Human embryos and bone marrow.

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13
Q

What is the purpose of stem cells in plants and animals?

A

To differentiate into a specific cell for the organism so it can work more efficiently

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14
Q

Compare adult stem cells and embryonic stem cells in animals

A
  • In adults stem cells can be found in bone marrow. It is not as versatile as embryonic stem cells (they can’t produce any type of cell, only certain ones) adult replace damaged cells.
  • Stem cells in embryos can produce any kind of cell which helps for growth and development.
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15
Q

Where are stem cells used in medicine?

A
  • To cure diseases such as sickle cell anaemia (transplant bone marrow)
  • Create specialised cells to replace damaged ones eg new cardiac muscle
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16
Q

Name some benefits of using stem cells in medicine

A
  • Replace old damaged cells (tissue)

- Create specialised cells

17
Q

Name some risks of stem cells

A
  • Tumour development - SC’s divide very quickly
  • Disease transmission - viruses living inside cells can be passed on to recipricant of stem cells
  • Rejection - transplanted cells aren’t grown using patients SC’s. Body may trigger immune response making susceptible to disease
18
Q

What is the brain made up of?

A

Billions of interconnected neurones

19
Q

What are the main parts of the brain? (and their roles)

A
  • Cerebrum - (largest) 2 hemispheres, right controls muscles on left side of body, also memory, language, vision and intelligence
  • Cerebellum - Muscle coordination and balance
  • Medulla oblongata - unconscious activities such as breathing, heart rate
20
Q

Describe process of CT scanning

A
  • X-rays used to produce brain image
  • Main structures (not function)
  • Shows diseased, damaged brain structure and where patient lost function
21
Q

Describe process of PET scanning

A
  • Use radioactive chemicals
  • More detailed than CT, shows structure and function in real time
  • Studies disorders in brain eg Alzheimers
22
Q

How is brain function observed?

A

Using PET scanners

23
Q

What are the effects of spinal chord damage?

A
  • Can stop neurones being transmitted around body

- Hard to reach to do treatment and could lead to permanent damage

24
Q

What damage can tumours do to the brain?

A
  • Damage tissues

- Clogs arteries and stops blood flow

25
Q

What are the limitations of brain surgery?

A

Some areas cannot be accessed making it impossible to surgically remove

26
Q

What are the parts of the nervous system? (order of a stimuli)

A
Stimulus
Receptor
Sensory neurone
CNS
Motor Neurone
Effector
Response
27
Q

What is the structure of a sensory neurone?

A

One long dendron and a short axon and have a myelin sheath to insulate and stop impulses escaping

28
Q

Identify parts of the eye and what they do

A

Cornea - refracts light into eye
Iris - controls amount of light let into eye
Lens - refracts light onto retina
Rods - sensitive to dim light, can’t sense colour
Cones - sensitive to colour, not dim light
Optic nerve - electrical impulses sent to brain

29
Q

What is colour blindness?

A

Red or green cones in retina aren’t working properly so hard to tell difference

30
Q

What is a cataract and how can it be corrected?

A

Cloudy patch on lens stopping light entering normally. Colours less vivid. Replace lens with artificial one.

31
Q

How can short-sightedness be corrected?

A

(Distant objects are hard to see). Concave lens used (in front)

32
Q

How can long-sightedness be corrected?

A

(Short distant is hard to see) Convex brought to focus from behind retina

33
Q

What is the structure of a motor neurone?

A

Long axon and short dendrites (can be myelinated)

34
Q

What is the structure of relay neurones?

A

Short dendrites carry impulse from sensory to cell body axon to motor neurones.

35
Q

What happens at a synapse?

A

Connection between two neurones

Nerve signal transferred by chemicals called neurotransmitters which diffuse across gap and slow due to diffusion