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Human Biosciences > CELLS > Flashcards

CELLS Flashcards

1
Q

2 types of cell

A

Eukaryotic cells

Prokaryotic cells

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2
Q

difference between eukaryotic and prokaryotic cells

A

Prokaryotic

  1. lack nucleus
  2. include 2 groups of bacteria - eubacteria & archaebacterial
  3. Absence of mitochondria
  4. Circular DNA

Eukaryotic

  1. Have a nucleus
  2. include animals, fungi, plants, protists
  3. Linear DNA
  4. Presence of mitochondria
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3
Q

similarity between eukaryotic and prokaryotic cells

A
  1. presence of plasma membrane

2. both bear ribosomes for protein synthesis

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4
Q

what is present in prokaryotic cells

A
  1. nucleoid
  2. plasma membrane
  3. capsule
  4. flagellum
  5. ribosomes
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5
Q

what is present in eukaryotic cells

A
  1. nucleus
  2. cytoplasm
  3. plasma membrane
  4. SER
  5. RER
  6. mitochondria
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6
Q

memorise plasma membrane structure

A

refer to saved image

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7
Q

function and structure of muscle cells

A

Contain numerous organelles providing

energy needed for muscle contraction

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8
Q

function and structure of nerve cells

A

Long and thin to carry impulses over distance

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9
Q

characteristic of plasma membrane

A
  • fluid mosaic model

- phospholipid bilayer

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10
Q

functions of plasma membrane

A
  1. physical isolation - barrier
  2. regulation of exchange of substances with environment - ions and nutrients enter, wastes eliminated, cellular products released
  3. sensitivity to environment - detect extracellular fluid composition and chemical signals
  4. structural support - anchors cells and tissues
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11
Q

characteristics of phospholipid bilayers

A
  1. hydrophilic heads - face outwards towards environment
  2. hydrophobic fatty acid tails - face inwards, sandwiched between heads
  3. barrier to ions and water-soluble compounds
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12
Q

function of cholesterol

A

helps to maintain cell membrane stability at varying

temperatures

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13
Q 
function of membrane carbohydrates
– glycoproteins and glycolipids
A

Identify the cell as “foreign” and act as receptors

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14
Q

Function of membrane proteins

A

Receptor proteins
• Bind and respond to ligands (ions, hormones)
– Carrier proteins
• Transport specific solutes through membrane
– Channels
• Regulate water flow and solutes passing through
membrane
• Channel ions for electrical impulse conduction
• Gated channels open or close to regulate
passage of substances

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15
Q

INFORMATION TRANSFERRED ACROSS PLASMA MEMBRANE

A

Receptor sites on receptor proteins are highly specific — interact specifically with signal molecules
• Receptors bind to molecules (such as hormones, drugs) with considerable specificity. The molecules and receptors fit like a key in a lock. Eg, Antidiuretic hormone only acts on kidneys.
• Different cell types have different receptor proteins
• A change is triggered within the cell as a result of
binding of signal molecule to receptor site

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16
Q

5 TYPES OF TRANSPORT ACROSS PLASMA MEMBRANE

A
  • Diffusion.
  • Osmosis.
  • Facilitated diffusion.
  • Active transport.
  • Endocytosis and exocytosis
17
Q

Diffusion

A

Random movement of molecules from a HIGHER CONCENTRATION to a LOWER CONCENTRATION down a CONCENTRATION GRADIENT.

18
Q

Osmosis

A

Random movement of water molecules from a HIGHER CONCENTRATION to a LOWER CONCENTRATION down a CONCENTRATION GRADIENT VIA A SEMI PERMEABLE MEMBRANE.

19
Q

Facilitated transport

A

The transport of molecules across the plasma
membrane from higher concentration to lower
concentration via a protein carrier

20
Q

Active transport

A

The movement of molecules from a lower to
higher concentration.
• May be too large to travel through membrane channels
• May not be lipid soluble
• May have to move against a concentration gradient

21
Q

Endocytosis

A

Transports molecules or cells into the cell via
invagination of the plasma membrane to form a
vesicle

22
Q

Exocytosis

A

Exocytosis transports molecules outside the cell
via the fusion of a vesicle with the plasma
membrane

23
Q

nucleus

A

• Control center of the cell
• Contains DNA
• DNA is made up of genes, which contain instructions
for the production of proteins.
• Nucleolus—dark region inside the nucleus.
• Produces ribosomes.
• Nuclear envelope —a double membrane around the nucleus.
• Nuclear pores —holes in the nuclear envelope; allow passage of substances in and out of nucleus

24
Q

cytoplasm

A 
– All materials inside the cell, outside of the nucleus
In the cytoplasm, 
• Cytosol (intracellular fluid)
– Contains dissolved materials
» Nutrients, ions, proteins, and waste
products
– High protein and potassium levels
– Low carbohydrate, lipid, amino acid, and
sodium levels
• Organelles
– Structures with specific functions
25
Q

ribosomes

A

Made of rRNA and protein.
• Sites of protein synthesis.
• Found attached to the endoplasmic reticulum or free floating in the cytoplasm.

26
Q

2 categories endoplasmic reticulum

A

Rough endoplasmic reticulum (RER)—studded with
ribosomes used to make proteins. synthesise proteins and packages in them vesicles.
Smooth endoplasmic reticulum (SER)—lacks ribosomes;
synthesizes lipids and other macromolecules.

27
Q

Golgi apparatus

A

Stack of flattened membranes associated with tiny vesicles
• modify and refine proteins and lipids from ER .
• Processes, packages, and secretes in vesicles

28
Q

Vesicles

A

Small membranous sacs functions to store,
transport, or digest cellular products and waste.
- do not just float about in the cytoplasm & docked onto filaments as microtubules and move like conveyor belts on these microtubules

29
Q

Lysosomes

A

contains digestive hydrolytic enzymes that break down cell parts or substances entering by vesicles into smaller parts.
• Prevalent in white blood cells that engulf disease causing microbes.

30
Q

Transport vesicles

A

takes protein to golgi apparatus

31
Q

Cytoskeleton

A

These are like bones in our body – only more easily
broken and fixed to form new shapes
• Dynamic structure of protein fibers that maintain cell
shape, anchor and/or move organelles in the cell.
• Plays important roles in both intracellular transport
(eg: the movement of vesicles and organelles)
• Cytoskeleton is responsible for chromosome movement during cell division

32
Q

Centrioles

A

Rod-shaped bodies made of microtubules

Form spindle apparatus during cell division, which helps move chromosomes.

33
Q

Centrosome

A

cytoplasm next to the nucleus that surrounds centrioles

34
Q

Mitochondria

A

site of cellular respiration and production of ATP

35
Q

Structure of Mitochondria

A
  • Has inner and outer membrane.

- Inner membrane is folded into cristae that contain enzymes for cellular respiration reactions.

36
Q

cilia

A
  • Cilia in the respiratory tract move mucus toward the
    throat.
  • Both are made of microtubules.
37
Q

flagella

A
  • Flagella on sperm propel them toward the egg

- Both are made of microtubules.

Human Biosciences (4 decks)

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