Cell Organelles 2 Flashcards

1
Q

What organelles will be studied in this?

5

A

Lysosomes

Peroxisomes

Vacuoles

Mitochondrion

Chloroplast

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2
Q

What are lysosomes?

A

Membranous sacs of hydrolytic enzymes, produced in the Golgi

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3
Q

What do the enzymes in lysosomes do?

A

They break down cellular waste products, fats, carbs and proteins which are then sent back to the cell to serve as building blocks for new products

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4
Q

List the functions of a lysosome.

2

A

Phagocytosis

Autophagy

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5
Q

Describe the phagocytosis function of lysosomes.

2

A

Cell engulfs microorganisms/large particles and then fusion with lysosome occurs

Digested products, simple sugars, amino acids pass into cytosol

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6
Q

Describe the autophagy function of lysosomes.

3

A

The recycling of cell’s own organic material

A damaged organelle becomes surrounded by membrane and fusion with lysosome occurs

The cell continually renews itself

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7
Q

Give an example of the phagocytosis process carried out by lysosomes.
(3)

A

A food vacuole containing molecules fuses with a lysosome

The lysosomes hydrolytic enzymes then digest the food particles

The digested products then pass into the cytosol

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8
Q

Give an example of the autophagy process carried out by lysosomes.
(3)

A

A damaged organelle e.g. a mitochondrion becomes surrounded by a membrane - becomes a vesicle

The vesicle now fuses with a lysosome

The lysosome’s hydrolytic enzymes digest the mitochondrion

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9
Q

How many enzymes do lysosomes have?

A

They have over 40 enzymes

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10
Q

Why do the lysosome’s enzymes need to be kept inside the lysosome?

A

They are acidic - have a low pH

They could digest the cell

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11
Q

Give four examples of enzymes/groups of enzymes found in lysosomes.

A

Lipase
Amylase

Proteases
Nucleases

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12
Q

What does lipase digest?

A

Lipids

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13
Q

What does amylase digest?

A

Carbohydrates

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14
Q

What do proteases digest?

A

Proteins

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15
Q

What do nucleases digest?

A

Nucleic acids

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16
Q

What are peroxisomes?

2

A

Specialised metabolic compartments bounded by a single membrane

Contain enzymes that transfer hydrogen

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17
Q

What do the peroxisome enzymes do?

2

A

These transfer hydrogen from various substrates to oxygen

Hydrogen peroxide (H2O2) is produced as a by-product

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18
Q

Give two examples of oxidative reactions.

A

The break down of fatty acids into smaller molecules that can be transported to mitochondria

The destruction of toxic molecules

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19
Q

What do the peroxisome enzymes do to hydrogen peroxide?

A

They convert it to water

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20
Q

How do you know what is a lysosome and what is a peroxisome under the microscope?

A

Lysosomes are larger and darker

Peroxisomes are smaller and lighter

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21
Q

What is a vacuole?

A

A membrane-bound sac

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22
Q

How is a vacuole formed?

A

It’s formed by pinching in of the plasma membrane

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23
Q

What are the two functions of a vacuole?

A

Storage of food and waste

Transport of products around the cell

24
Q

What is the endomembrane system?

A

A group of cell membranes and organelles that are mutually interconnected, either by being directly continuous with one another or by sending one another vesicles

25
Q

What organelles form the endomembrane system?

6

A

Nuclear envelope

Endoplasmic reticulum

Golgi apparatus

Lysosomes

Vacuoles

Plasma membrane

26
Q

What is the mitochondrion?

3

A

The powerhouse of the eukaryotic cell

It produces almost all ATP to drive cellular reactions

A semi-autonomous cell organelle (division, fusion, own genetic system)

27
Q

What processes can a mitochondria carry out on it’s own?

A

Division

Fusion

*it also has it’s own genetic system

28
Q

What does a mitochondria need to take in from the cytoplasm?

A

Mitochondria need to take in over 99% of proteins from cytoplasm

29
Q

What did mitochondria evolve from?

4

A

Mitochondria evolved from a prokaryote

First, a nucleated cell engulfed a prokaryote

Symbiosis then developed

Prokaryote developed into an energy producing mitochondrion

30
Q

Describe the structure of a mitochondrion.

7

A

An outer membrane which is permeable to small molecules

An inner membrane which is the site of cellular respiration and ATP synthesis

Intermembrane space

Cristae

Matrix

Matrix granules

Ribosomes

31
Q

What happens at the inner membrane of a mitochondrion?

A

The inner membrane is the site of cellular respiration and ATP synthesis

32
Q

Write a note on the outer membrane of a mitochondrion.

2

A

The outer membrane contains integral proteins called porins

These allow molecules to freely diffuse from one side of membrane to other

33
Q

What are porins?

A

Integral proteins

34
Q

What do porins do?

A

They allow molecules to freely diffuse from one side of a membrane to the other

35
Q

Write a note on the intermembrane space of a mitochondrion.

2

A

This is the space between the outer and inner membrane

The outer membrane is freely permeable to small molecules so the concentrations of ions and sugars in this space is the same as the cytosol

36
Q

Where is the intermembrane space of a mitochondrion found?

A

Between the outer membrane and inner membrane

37
Q

What concentrations need to be considered in order for molecules to move across the intermembrane space of a mitochondrion?

A

The concentrations of ions and sugars in the intermembrane space must be the same as the mitochondrion

38
Q

Write a note on the inner membrane of a mitochondrion.

3

A

This is a double phospholipid layer

This is the site of ATP production

Cristae folds allow more surface area so that ability to produce ATP is enhanced

39
Q

What are the foldings of the mitochondrion’s inner membrane called?

A

Cristae

40
Q

What is the function of cristae in a mitochondrion?

A

Cristae all more surface area for ATP production

41
Q

Write a note on the matrix of a mitochondrion.

2

A

This is the fluid that fills the area inside the inner membrane

It is important for ATP production with the aid of ATP synthase contained in inner membrane

42
Q

List the functions of the mitochondrion.

5

A

Energy production

To produce enzymes

To produce heat

To signal transduction (calcium ions)

Cell proliferation/growth

43
Q

How does mitochondria produce energy?

2

A

The conversion of nutrients into energy yielding molecules (ATP) to fuel the cells activities

This is known as aerobic respiration

44
Q

What are the enzymes produced by mitochondria used for?

A

These enzymes are used for the metabolic conversion of food to energy

45
Q

How do mitochondria produce heat?

A

Through proton leakage

46
Q

How is mitochondrial DNA passed on?

2

A

Mothers give genes (nucleus) and cytoplasm (mitochondria) to their children in their egg cells

Fathers only give genes (nucleus)

47
Q

How does mtDNA compare to nuclear DNA?

A

mtDNA has a high mutation rate compared to nuclear DNA

48
Q

Where are chloroplasts found?

A

Only found in animal cells

49
Q

What do chloroplast do?

A

They convert light energy to chemical energy (food)

50
Q

List the parts of a chloroplast.

5

A

Membrane

Stroma

Lamella

Thylakoids (individual units)

Granum (stack)

51
Q

Write a note on the stroma of the chloroplast.

2

A

The aqueous fluid of chloroplast

The stroma contains the chloroplast DNA and ribosomes (allow it to replicate autonomously)

52
Q

Write a note on the lamella of the chloroplast.

A

The lamella are internal membranes with stacks of hollow disks called thylakoids

53
Q

What are the thylakoids of the chloroplast.

A

These are stacks of hollow disks that form part of the lamella

54
Q

What is an individual stack of thylakoids?

A

Granum

55
Q

Where is chlorophyll contained in a chloroplast?

A

Chlorophyll is contained in the thylakoids