Cell ultrastructure Flashcards by Lauren Stanton

Define compartmentalisation

Internal structure of a cell can be divided up into areas specialised for certain functions

How well did you know this?

Not at all

Perfectly

Average diameter of nucleus

10-20 micrometers

How well did you know this?

Not at all

Perfectly

How many nuclear pores does the nucleus have? (and diameter of them)

3000 nuclear pores, 40-100nm each

How well did you know this?

Not at all

Perfectly

What is the function of nuclear pores

Allow passage of large molecules out of the nucleus e.g. mRNA

How well did you know this?

Not at all

Perfectly

What does the nucleoplasm consist of?

Chromatin and nucleolus

How well did you know this?

Not at all

Perfectly

Function of nucleus:

control cells activities via production of mRNA

How well did you know this?

Not at all

Perfectly

Function of nucleolus:

produce ribosomal RNA and assembles ribosomes

How well did you know this?

Not at all

Perfectly

Length of mitochondria

1-10 micrometers

How well did you know this?

Not at all

Perfectly

Outer membrane mitochondria function

Control materials entering/exiting

How well did you know this?

Not at all

Perfectly

Inner membrane of mitochondrion is folded to form the

Cristae

How well did you know this?

Not at all

Perfectly

Why does the cristae have a large SA?

Enzymes involved in synthesis of ATP to be attached to

How well did you know this?

Not at all

Perfectly

Liquid inside the cristae is called the

Matrix

How well did you know this?

Not at all

Perfectly

Matrix contains:

proteins, lipids, circular DNA

How well did you know this?

Not at all

Perfectly

Function of mitochondria:

later stages of aerobic respiration, produce ATP.

How well did you know this?

Not at all

Perfectly

What is the ER made of?

Cisternae (flattened sheets) and sacs

How well did you know this?

Not at all

Perfectly

SER function:

Synthesise, store and transport lipids and carbohydrates

How well did you know this?

Not at all

Perfectly

SER appearance:

Smooth and tubular

How well did you know this?

Not at all

Perfectly

RER function:

Protein synthesis, pathway for transporting proteins and other materials through a cell

How well did you know this?

Not at all

Perfectly

RER appearance:

Ribosomes attached

How well did you know this?

Not at all

Perfectly

Ribosomes diameter

20-30 micrometers

How well did you know this?

Not at all

Perfectly

Ribosomes are not

membrane-bound

How well did you know this?

Not at all

Perfectly

What are ribosomes made out of?

rRNA and protein

How well did you know this?

Not at all

Perfectly

What do ribosomes consist of?

Small subunit and large subunit

How well did you know this?

Not at all

Perfectly

Where are ribosomes found?

Free in cytoplasm or associated with RER

How well did you know this?

Not at all

Perfectly

SSU size

40S

LSU size

60S

S stands for Svedburg unit:

Sedimentation rate of particles

Function of ribosomes:

Join amino acids together in a specific order, dictated by mRNA molecules

What does the SSU and LSU do?

SSU reads RNA and LSU joins amino acids together forming a polypeptide chain

What is the golgi apparatus made from?

Cisternae and vesicles

How many stacks does a golgi body have?

40-100 stacks, with 3-6 cisternae per stack

Function of golgi apparatus:

Assemble polypeptides into proteins, pack proteins into vesicles for secretion by exocytosis, protein modification

Describe protein modification after they have arrived from the RER.

Proteins are modified by adding non-protein portions. | Proteins are labelled so that they can be transported to the correct part of the cell.

What are vesicles?

Little round things which contain fluid and transport materials

What produces lysosomes?

Golgi apparatus

How many enzymes so lysosomes contain?

Up to 50

What is the diameter and pH of lysosomes?

1 micrometer, pH of 5

Function of lysosomes:

digest unwanted materials in the cytoplasm, fuse with phagocytic vesicles so enzymes can digest pathogens

What are centrioles made from?

Tubulin

What is tubulin organised into?

Microtubules

9+0 pattern of microtubules

Nine outer microtubules and none in the centre

Function of centrioles:

Organising spindle fibres which are used in cell division

What is a centrosome?

Pair of centrioles associated with nuclear membrane

One a centrosome duplicates, each centrosome with have a mother and a new centriole which are arranged at

Right angles to each other

During mitosis the centrosomes

Migrate to opposite poles so that each daughter cell receives one centrosome

Structure of a palisade mesophyll cell

Upper epidermis, palisade mesophyll cells, spongy mesophyll cells, lower epidermis

Diameter of chloroplasts

1 micrometer

Length of chloroplasts

2-10 micrometers

Outer chloroplast membrane function:

Allows small molecules and ions to diffuse across

Inner chloroplast membrane function:

Controls passage of materials into and out of the strome

Thylakoid system position:

Suspended in the stroma

Stroma definition:

Where light independent stage of photosynthesis takes place

A large permanent vacuole contains:

Mainly water

Membrane of vacuole is called a

Tonoplast

What is dissolved in the water of a vacuole?

Salts, sugars, organic acids

Cell vacuole purpose:

Supports plant and maintains shape, stops animal cells from bursting (if present temporarily)

What is the cell wall made from?

Cellulose

What are cellulose microfibrils held together by?

Hydrogen bonds which form cross links, giving the cell wall strength

Cell wall purpose:

Stops cell from bursting when water enters from osmosis, shape and strength of cell.

Cell wall thickness

10-80nm

Mesosome definition

Infolding of cell membrane

Pili

Hair-like projections for attachment to other cells

Ribosomes in prokaryotic cells are

smaller than eukaryotic cells

Flagellum is used for

Movement

What does the word prokaryote mean?

Before nucleus

What do prokaryotes not have?

A nucleus