Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Yr12 Bio Eukaryotic Cells > Eukaryotic Cells > Flashcards

Eukaryotic Cells Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What is the Nucleus? What are the functions?

A

The nucleus contains the organism’s hereditary material and controls the cell’s activities.

Around 10-20um in diameter.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the functions of the Mitochondria?

A
  • Site of aerobic stages of respiration
  • Production of energy carrier molecule ATP from respiratory substrates such as glucose

Appearance: Mitochondria are usually rod shaped and 1-10um in length.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Chromosomes

A

Consist of protein-bound, linear DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the cell wall? What are the functions?

A

Cell wall consists of microfibrils of the polysaccharide cellulose, embedded in a matrix. Cellulose microfibrils have considerable strength and so contribute to the overall strength of the cell wall.

Features:

  • consist number of polysaccharides, eg cellulose
  • There is a thin layer, called the middle lamella, which marks the boundary between adjacent cell walls and cements adjacent cells together.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Nucleolus

A

Small spherical region within the nucleoplasm.

Manufactures rRNA and assembles ribosomes.

There may be more than 1 nucleolus in 1 nucleus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are lysosomes? How are they formed?

A

Lysosomes are formed when the vesicles produced by the Golgi apparatus contain enzymes such as proteases and lipases.

They also contain lysozymes, enzymes that hydrolyse the cell walls of certain bacteria.

As many as 50 such enzymes may be contained in a single lysosome.

Up to 1um in diameter, lysosomes isolate these enzymes from the rest of the cell before releasing them, either to the outside or into a phagocytic vesicle within the cell.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the cell walls of algae and fungi made of?

A

Algae : made of either cellulose or glycoproteins, or a mixture of both

Fungi: do not contain cellulose but comprise a mixture of a nitrogen containing polysaccharide called chitin, a polysaccharide called glycan and glycoproteins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the Golgi apparatus?

A

Occurs in almost all eukaryotic cells, similar to SER in structure except more compact.

Consists of stack of membranes that make up flattened sacs called cisternae, with small rounded hollow structures called vesicles.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Smooth Endoplasmic Reticulum

A

SER lacks ribosomes on its surface and is often more tubular in appearance.

Functions:

  • synthesise, store and transport lipids
  • Synthesise, store and transport carbohydrates.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is known as the ultra structure of the cell?

A

Cells are often adapted to perform a particular function. Depending on that function, each cell type has an internal structure that suits it for its job. This is known as the ultrastructure.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are ribosomes? What are the 2 types?

A

Ribosomes are small cytoplasmic granules found in all cells. They may occur in the cytoplasm or be associated with the RER.

Two types:

80S - found in eukaryotic cells, around 24nm in diameter

70s - found in prokaryotic cells, mitochondria and chloroplasts, slightly smaller.

Ribosomes have two subunits - one large and one small, each contains rRNA and protein.

Despite their small size, they occur in vast numbers that they can account for up to 25% of the dry mass of a cell. Ribosomes are the site of protein synthesis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the functions of the nucleus? (3)

A
  • Act as the control centre of the cell through the production of mRNA and tRNA and hence protein synthesis.
  • Retain the genetic material of the cell in the form of DNA and chromosomes.
  • Manufacture rRNA and ribosomes.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the functions of the nucleus? (3)

A
  • Act as the control centre of the cell through the production of mRNA and tRNA and hence protein synthesis.
  • Retain the genetic material of the cell in the form of DNA and chromosomes.
  • Manufacture rRNA and ribosomes.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the Stroma? (Chloroplast)

A

Stroma is the fluid filled matrix where the second stage of photosynthesis (synthesis of sugars) takes place.

Within the stroma are other structures eg starch grains.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the chloroplast envelope? (Chloroplasts)

A

Double plasma membrane that surrounds the organelle.

It’s highly selective in what it allows to enter and leave the chloroplast.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the Endoplasmic reticulum? What are the two types?

A

ER is an elaborate, 3D system of sheet like membranes, spreading through the cytoplasm of the cells.

It is continuous with the outer nuclear membrane. The membranes enclose a network of tubules and flattened sacs called cisternae.

  • Smooth ER
  • Rough ER
17
Q

What are the functions of the Golgi apparatus?

A
  • add carbohydrates to proteins to form glycoproteins
  • Produce secretory enzymes eg those secreted by the pancreas
  • Secrete carbohydrates eg those used in making cell walls in plants
  • Transport, modify and store lipids
  • Form lysosomes

The Golgi apparatus is especially well developed in secretory cells, eg epithelial cells.

18
Q

What are the functions of a cellulose cell wall?

A

Functions of the cellulose cell wall are:

  • provide mechanical strength in order to prevent the cell bursting under the pressure created by the osmotic entry of water
  • To give mechanical strength to the plant as a whole
  • To allow water to pass along it and contribute to the movement of water through the plant
19
Q

What are grana? (Chloroplasts)

A

Grana are stacks of up to 100 disc-like structures called thylakoids.

Within the layer of thylakoids is the photosynthetic pigment called chlorophyll.

Some thylakoids have tubular extensions that join up with thylakoids in adjacent grana.

The grana are where the first stage of photosynthesis (light absorption) takes place.

20
Q

What does the double membrane of the mitochondria do?

A

Controls the entry and exit of material. It is around the mitochondria.

The inner of the two membranes is folded to form extensions known as cristae.

21
Q

What is the cristae? (Mitochondria)

A

Extensions of the inner membrane. In some species this extends across the whole width of the mitochondria.

Cristae provide a large surface areas for the attachment of enzymes and other proteins involved in respiration.

22
Q

What is the cristae? (Mitochondria)

A

Extensions of the inner membrane. In some species this extends across the whole width of the mitochondria.

Cristae provide a large surface areas for the attachment of enzymes and other proteins involved in respiration.

23
Q

Nucleoplasm

A

Granular, jelly like material that makes up the bulk of the nucleus.

24
Q

What are chloroplasts?

A

The organelles that carry out photosynthesis. Vary in shape and size but typically disc-shaped, 2-10um long and 1um in diameter.

25
Q

Rough Endoplasmic Reticulum

A

RER has ribosomes present on the outer surface of the membranes.

Functions:

  • Provide large SA for the synthesis of proteins and glycoproteins.
  • Provide a pathway for the transport of materials, especially proteins throughout the cell.
26
Q

What makes eukaryotic cells different from prokaryotic cells?

A

Eukaryotic cells has a distinct nucleus and possesses membrane bound organelles

27
Q

What are the functions of lysosomes?

A
  • Hydrolyse material ingested by phagocytic cells, such as WBC
  • release enzymes to the outside of the cell (exocytosis) in order to destroy material around the cell.
  • Digest worn out organelles so that the useful chemicals they are made of can be re-used
  • Completely break down cells after they have died (autolysis)
28
Q

Nuclear pores

A

Allow the passage of large molecules, eg mRNA, out of the nucleus.

Typically around 3000 pores in each nucleus.

40-100nm in diameter.

29
Q

How are chloroplasts adapted to their function?

A

Granal membranes provide a large surface area for the attachment of chlorophyll, electron carriers and enzymes that carry out the first stage of photosynthesis in a very strict order.

Fluid of the stroma possesses all the enzymes needed to make sugars in the second stage of photosynthesis.

Chloroplasts contain both DNA and ribosomes so they can quickly and easily manufacture some of the proteins needed for photosynthesis.

30
Q

What are vacuoles?

A

A fluid filled sac bound by a single membrane.

Within mature plant cells there is usually one large central vacuole. The single membrane around it is called the tonoplast.

A plant vacuole contains a solution of mineral salts, sugars, amino acids, wastes and sometimes pigments such as anthocyanins.

Functions:

Support herbaceous plants, and herbaceous parts of woody plants by making cells turgid.

Sugars and amino acids may act as a temporary food store.

Pigments may colour petals to attract pollinating insects.

31
Q

Nuclear Envelope

A

A double membrane that surrounds the nucleus. Its outer membrane is continuous with the endoplasmic reticulum of the cell and often has ribosomes on the surface.

Controls entry and exit of materials in and out of the nucleus. Contains the reactions taking place within it.

32
Q

What does the Golgi apparatus do?

A
  • Proteins and lipids produced by the ER are passed through the GA in a strict sequence.
  • modifies these proteins often adding non-protein components, such as carbohydrates to them.
  • labels them allowing to be accurately sorted and sent to their correct destinations.
  • Once sorted, the modified proteins and lipids are transported in the Golgi vesicles which are regularly pinched off from the the ends of the Golgi cisternae.
  • These vesicles may move to the cell surface, where they fuse with the membrane and release their contents to the outside.
33
Q

What is the matrix? (Mitochondria)

A

The matrix makes up the remained of the mitochondrian.

Contains proteins, lipids, ribosomes and DNA that allows the mitochondria to control the production of some of their own proteins.

Many enzymes involved in respiration are found in the matrix.

Yr12 Bio Eukaryotic Cells (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions