Lecture 1 (chapter 1.2, 1.3)

Question 1

What are the tenets of the cell theory?

Answer 1

• All organisms are composed of one or more cells
• The cell is the structural unit of life
• Cells can arise only by division from a preexisting cell

Question 2

Why do cells internally program themselves to die?

Answer 2

Cells are no longer needed or pose a risk of becoming cancerous

Question 3

What sort of movement are atoms in a constant state of?

Answer 3

random (stochastic) propelled by thermal energy they acquire from their environment

Question 4

What is a protein?

Answer 4

polypeptide chains consisting of hundreds of amino acid building blocks that fold into a precise three-dimensional structure

Question 5

Where is genetic information stored?

Answer 5

DNA which is packaged into a set of chromosomes that occupy the space of a cell nucleus

Question 6

What do genes do?

Answer 6

Genes facilitate the construction of cellular structures, the directions for running cellular activities and the program to duplicate themselves

Question 7

What division is it when the mother cell unequally divides leaving one of the cells retaining nearly all of the cytoplasm despite receiving half the genetic material?

Answer 7

When a human oocyte divides

Question 7

What division is it when the mother cell unequally divides leaving one of the cells retaining nearly all of the cytoplasm despite receiving half the genetic material?

Answer 7

When a human oocyte divides

Question 8

What is an enzyme?

Answer 8

Molecules that greatly increase the rate at which a chemical reaction occurs

Question 9

Define metabolism

Answer 9

The sum total of the chemical reactions in a cell

Question 10

Features held in common by prokaryotic and eukaryotic cells

Answer 10

• Genetic information encoded in DNA
• Both have DNA-containing chromosomes
• Similar mechanisms for transcription and translation (including similar ribosomes)
• Similar apparatus for conservation of chemical energy as ATP
• Similar mechanism for synthesising and inserting membrane proteins
• Plasma membranes and Proteasomes (protein digesting structures) of similar construction

Question 11

Features of eukaryotic cells not found in prokaryotes

Answer 11

• Division of cells into nucleus and cytoplasm, separated by a nuclear envelope containing complex pore structures
• Complex chromosomes and associated proteins capable of compacting into mitotic structures
• Complex membranous cytoplasmic organelles (e.g endoplasmic reticulum, Golgi complex, lysosomes)
• Specialised cytoplasmic organelles for aerobic respiration (mitochondria/chloroplasts)
• Complex cytoskeletal system (e.g actin filaments) and complex flagella and cilia
• Ability to ingest material by enclosure within plasma membrane vesicles (phagocytosis)
• Cell division using a microtubule-containing mitotic spindle that separates chromosomes
• Presence of two copies of genes per cell (diploidy), one from each parent
• Presence of three different RNA synthesising enzymes (RNA polymerases)
• Sexual reproduction requiring meiosis and fertilisation

Question 12

What is a nucleoid?

Answer 12

A poorly demarcated region of the cell that lacks a boundary membrane to separate it from the surrounding cytoplasm

Question 13

What is a nucleus?

Answer 13

A region bounded by a complex membranous structure called the nuclear envelope

Question 14

What is a chromatin?

Answer 14

A complex nucleoprotein that is formed when chromosomal DNA of eukaryotes is tightly associated with proteins

Question 15

What is mitochondria?

Answer 15

Where chemical energy is made available to fuel cellular activities

Question 16

What is an endoplasmic reticulum?

Answer 16

Where many of a cell’s proteins and lipids are manufactured

Question 17

What is a Golgi complex?

Answer 17

Where materials are sorted, modified and transported to specific cellular destinations

Question 18

How does material move within a prokaryotic cell?

Answer 18

Simple Diffusion

Question 19

What is the definition of Biofilms?

Answer 19

Complex, multispecies communities (typically associated with prokaryotic cells)

Question 20

How does material move within a eukaryotic cell?

Answer 20

Cytoplasmic membranes of eukaryotic cells form a system of interconnecting channels and vesicles that function in the transport of substances from one part of a cell to another, as well as between the inside of the cell and its environment

Question 21

When was the first culture of human cells begun and from what was it obtained from?

Answer 21

1951, the cells were obtained from a malignant tumour and named “HeLa” cells after the donor

Question 22

What is the hierarchical organisation of living systems?

Answer 22

Cellular level
Organismal level
Populational level
Ecosystem level

Question 23

What are the two streams of chemical reactions that occur in cells?

Answer 23

Catabolic pathways and Anabolic pathways

Question 24

What is the purpose of cell receptors?

Answer 24

A cell’s receptors provide pathways through which external stimuli can evoke specific responses in target cells

Question 25

What are some ways cells respond to specific stimuli?

Answer 25

• alter their metabolic activity
• moving from one place to another
• committing suicide

Question 26

What do cells possess receptors for?

Answer 26

• Hormones
• Growth factors
• Extracellular materials
• Substances on the surfaces of other cells

Question 27

What did the 1891 experiment conducted by Hans Driesch, a German Embryologist, entail?

Answer 27

He found that he could completely separate the first two or four cells of a sea urchin embryo and each of the isolated cells would proceed to develop into a normal embryo

Question 28

How is the proportion of oxygen different in lipids and carbohydrates?

Answer 28

The proportion of oxygen in lipids is less than in carbohydrates

Question 29

What is molecular biology?

Answer 29

The study of the chemical structures and processes of biological phenomena that involve the basic units of life

Question 30

What are organic compounds and what are the different types?

Answer 30

Organic compounds are carbon based. They are linear, cyclic and aromatic.

Question 31

What do the attached functional groups determine?

Answer 31

• Physical properties
• Reactivity
• Solubility in aqueous solutions of organic and all chemical compounds

Question 32

How do fats act as chemical energy stores?

Answer 32

Fats are rich in chemical energy and a gram of fat contains over twice the energy content of a gram of carbohydrates

Carbohydrates function as short term energy stores and fat acts as a long term energy supply

Question 33

What are adipocytes?

Answer 33

Cells specialised for fat storage, breakdown and synthesis.

Fats are insoluble in water and stored in adipocytes which contain one large or multiple smaller lipid globules