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Y3 Biology > CH 1: Cell Structure and Organisation > Flashcards

CH 1: Cell Structure and Organisation Flashcards

1
Q

Describe the functions of a light microscope.

A
  • magnifies up to 1000x
  • image produced is coloured
  • image produced is 2D
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2
Q

Describe the functions of an electron microscope.

A
  • magnifies up to 200 000x and ultrastructure of cells can be seen.
  • image produced is black-and-white and can be artificially coloured
  • image produced is 3D
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3
Q

What is the magnification equation?

A

Image size = actual size x magnification

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4
Q

What is a cell?

A

A cell is a fundamental building block and a basic structural unit of life

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5
Q

What are cells made of?

A

Biological molecules such as nucleic acids, proteins, carbohydrates and lipids.

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6
Q

What are the 2 type of cells?

A

prokaryotes and eukaryotes

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7
Q

Describe the characteristics of prokaryotes.

A
  • smaller
  • simpler internal structure without compartments
  • lack true nucleus and membrane-bound organelles -> instead contains a singular circular DNA and multiple plasmids
  • Contain cell wall, plasma membrane, cytoplasm, ribosomes and flagellum
  • All bacteria are Prokaryotes
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8
Q

Describe the characteristics of eukaryotes.

A
  • larger
  • compartmentalised internal cell structure and membrane-bound organelles
  • contain PLASMA MEMBRANE, CYTOPLASM, MITOCHONDRIA, RIBOSOMES and a distinct NUCLEUS
  • genetic material in the form of multiple strands of CHROMATIN
  • algae, protozoa, fungi, plants and animals
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9
Q

Compare the similarities of prokaryotes and eukaryotes.

A

Both have a plasma membrane, cytoplasm, genetic material and ribosomes

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10
Q

What is a plasma membrane + its function

A
  • a SELECTIVELY permeable phospholipid bilayer membrane
  • separates the organelles in the cytoplasm from its external aqueous environment
  • controls the movement of substances in and out of the cell.
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11
Q

Distinguish between a ‘partially permeable membrane’ and a ‘selectively permeable membrane’.

A

partially permeable: only allows smaller molecules to pass through and excludes larger molecules.

selectively permeable: able to regulate the movement of substances according to the needs of the cell.

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12
Q

What is the function of the cell wall?

A
  1. Gives cell fixed shape
  2. Resist expansion when water enters through osmosis, preventing cell lysis
  3. protect from mechanical damage
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13
Q

What is the cell wall made of?

A

Cellulose > makes cell wall inelastic

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14
Q

What is the cytoplasm

A
  • an aqueous medium
  • contains dissolved substances and enzymes
  • is a site where cellular reactions occur
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15
Q

Define what an organelle is.

A

A cellular structure that performs a specific function within a cell.

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16
Q

How do organelles in a cell work together?

A

Various organelles work together to perform cellular activities such as cellular respiration.

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17
Q

List the parts of a nucleus.

A
  • nuclear envelope
  • nucleolus
  • chromatin
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18
Q

The nuclear envelope is __layered

A

Bilayered

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19
Q

Functions of the nucleus.

A
  • CONTROLS activities such as cell growth and repair
  • contains genetic information (DNA) in the form of chromatin > essential for cell division
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20
Q

Function of nucleolus

A

Synthesises ribosomes

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21
Q

Describe the structure of chromatin

A
  • Long thread-like
  • made of proteins and deoxyribonucleic acid (DNA)
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22
Q

What is the function of DNA?

A
  • stores genetic material
  • carries instructions that cells need for carrying out its activities.
23
Q

When does chromatin form chromosomes?

A

During CELL DIVISION, chromatin will shorten and condense into tightly coiled structures.

24
Q

Structure of Rough Endoplasmic Reticulum (RER)

A

A NETWORK of FLATTENED membrane-bound sacs lined with ribosomes.

25
Function of the Rough Endoplasmic Reticulum.
Protein synthesis. The polypeptide chain synthesised by the ribosomes will be FOLDED in the RER + PACKAGED into transport vesicles which move to the Golgi body for secretion out of the cell.
26
What are the 2 types of ribosomes.
Free and bound ribosomes
27
Contrast the STRUCTURE and FUNCTION free and bound ribosomes.
Free ribosomes: - lie freely in the cytoplasm - synthesise proteins that are used within the cytoplasm of the cell Bound ribosomes: - attached to the membrane of RER - synthesise proteins that are transported out of the cell.
28
Describe the structure of Smooth Endoplasmic Reticulum.
Tubular
29
Function of the Smooth ER
1. synthesises LIPIDS such as phospholipids and steroid hormones. 2. BREAKS DOWN harmful substances into harmless substances through DETOXIFICATION.
30
Describe the structure of the Golgi apparatus.
consists of stacks of membrane-bound sacs
31
Function of the Golgi apparatus.
1. Chemically modifies products (proteins and lipids) made by the ER 2. stores and packages these substances in the vesicles for secretion out of the cell
32
Describe the process of how proteins made by the RER are moved out of the cell.
1. polypeptide chains are synthesised at the ribosomes and FOLDED TO FORM PROTEINS the RER 2. transport vesicles containing substances (e.g proteins and lipids) made by the ER are pinched off from ER 3. vesicles fuse and release their substances into the golgi apparatus. 4. substances are chemically modified and packed in the golgi apparatus. 5. secretory vesicles containing the modified substances pinch off the golgi body 6. secretory vesicles move towards and fuse with the plasma membrane, releasing their substances.
33
Describe the structure of a mitochondrion
- small and cylindrical - bound by double membrane
34
Function of mitochondria
It is the **site for aerobic respiration** where **Adenosine Triphosphate (ATP) is produced** to power various cell activities (e.g. secretion, cell division, enzyme production, etc.)
35
Why is the membrane in the mitochondria folded?
increase SA > increase rate of aerobic respiration + ATP production
36
Describe the structure of chloroplast
Oval shaped double membrane-bound organelle.
37
Function of chloroplast
Contains a green pigment > chlorophyl > essential for absorbing sunlight for photosynthesis
38
Difference between the structure of plant and animal cells.
1. Plant cells have a cell wall while animal cells do not. 2. Plant cells contain chloroplast while animal cells do not 3. Plant cell have a LARGE CENTRAL VACUOLE that is PERMANENT while animal cell MANY SMALL VACUOLES that are TEMPORARY
39
The vacuole of the plant cell is enclosed by single selectively permeable membrane called the _______.
Tonoplast
40
Function of vacuole in plant cell
1. contains DISSOLVED SUBSTANCES such as sugars, waste products and amino acids. 2. maintains water potential of the cell by ABSORBING and EXPELLING water in the cell
41
Function of vacuoles in animal cell
contain water and food substances
42
Which 4 organelles have double membrane?
1. nucleus 2. chloroplast 3. mitochondria 5. plasma membrane
43
Define 'differentiation’
The process by which a cell becomes specialised by developing SPECIFIC structures to perform a SPECIFIC function.
44
Adaptations of red blood cell.
1. contain haemoglobin (a red pigment) which binds oxygen 2. circular biconcave shape > increases SA-to-vol ratio > oxygen can diffuse in and out of the cell at a HIGHER rate 3. lack nucleus > store more haemoglobin > transport of oxygen 4. small and flexible > squeeze through capillaries easily
45
Adaptations of muscle cell
- elongated and cylindrical - contains many nuclei and mitochondria > provide energy for contraction of muscle cell
46
Adaptation of root hair cell
long and narrow > increase SA-to-vol ratio > absorb water and mineral salts at a higher rate
47
Definition of a tissue
A group of cells that develop in the same way and have the SAME STRUCTURE AND FUNCTION.
48
Definition of an organ
A group of tissues that **form a single structure** to **perform a specific function**.
49
Definition of an organ system
A group of organs within an organism that function collectively to carry out a particular process.
50
What are the differences between the structure of a bacterial cell and virus?
1. Outer covering Bacterial cell > cell wall viruses > protein coat 2. Genetic info Baterial cell > DNA Viruses > DNA or RNA 3. Cellular structures Bacterial cell > contains cell wall, cytoplasm and ribosomes Viruses> no cellular structure or organelles
51
What living characteristics do viruses have?
can reproduce when it enters a host cell
52
What non-living characteristics do viruses have?
- no cellular structures or organelles - do not carry out cellular activities (grow, move, feed, respirate or excrete)
53
Why can viruses only reproduce when they have a host?
- do not have any cellular structures or organelles - host cell contains ENZYMES and ORGANELLES like ribosomes that are **necessary for reproduction**

Y3 Biology (5 decks)

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