Chapter 2 - basic components of living systems Flashcards
1
Q
what is magnification?
A
how many times larger the image is than the actual size of the object being viewed
2
Q
what is resolution?
A
the ability to see individual objects as separate entities
3
Q
transmission electron microscope (TEM)
A
- a beam of electrons is transmitted through a specimen and focused to produce an image
- resolution power 0.5nm
4
Q
scanning electron microscope (SEM)
A
- a beam of electrons sent across the surface of a specimen and the reflected electrons are collected
- resolution power 3-10nm
- produce 3D images of surface
5
Q
laser scanning confocal microscope
A
- moves a single spot of focused light across a specimen
- very thin sections of specimen examined
- light from elsewhere removed
- produce very high resolution images
- non invasive
6
Q
what is the nucleus?
A
- contains coded genetic info in form of DNA
- has a nuclear envelope (double membrane) that contains nuclear pores allowing molecules to move in and out of nucleus
7
Q
what is DNA?
A
- directs the synthesis of proteins
- controls metabolic activity of the cell
- associates with proteins called histones to form chromatin (forms chromosomes)
8
Q
what is the nucleolus?
A
- an area within the nucleus responsible for producing ribosomes
- composed of proteins and RNA (RNA used to produce rRNA)
9
Q
what is the structure mitochondria?
A
- double membrane
- inner membrane folded to form cristae
- fluid interior called matrix
10
Q
what is the function of the mitochondria?
A
- site of the final stages of cellular respiration
- produces ATP
11
Q
what are vesicles?
A
- membranous sacs
- have storage and transport roles
- used to transport materials inside the cell
12
Q
what are lysosomes?
A
- specialised forms of vesicles
- contain hydrolytic enzymes
- break down waste material in cells
- responsible for breaking down pathogens ingested by phagocytic cells
13
Q
what is the cytoskeleton?
A
- a network of fibres necessary for the shape and stability of a cell
- holds organelles in place and controls movement of the cell and organelles
14
Q
what are the three components of the cytoskeleton?
A
- microfilaments: contractile fibres formed from protein actin, responsible for cell movements and contraction during cytokinesis
- microtubules: globular tubulin proteins polymerised to form tubes, determine the shape of the cell, e.g. spindle fibres
-intermediate fibres: give mechanical strength to cells, help maintain integrity
15
Q
what are centrioles?
A
- composed of microtubules
- involved in the assembly and organisation of spindle fibres during cell division