IAL Biology Unit 2

Topic 3 – Cell Structure, Reproduction and Development

3.1 Cell Basics

Know that all living organisms are made of cells , sharing some common features

3.2 Organization of Multicellular Organisms

Understand how the cells of multicellular organisms are organised into tissues , tissues into organs , and organs into organ systems

3.3 Ultrastructure of Eukaryotic Cells

(i) Know the ultrastructure of eukaryotic cells , including nucleus , nucleolus , ribosomes , rough endoplasmic reticulum (rER) , smooth endoplasmic reticulum (sER) , mitochondria , centrioles , lysosomes and Golgi apparatus

(ii) Understand the function of the organelles listed in (i)

3.4 Protein Transport within Cells

Understand the role of the rough endoplasmic reticulum (rER) and the Golgi apparatus in protein transport within cells , including their role in the formation of extracellular enzymes

3.5 Ultrastructure of Prokaryotic Cells

(i) Know the ultrastructure of prokaryotic cells , including cell wall , capsule , plasmid , flagellum , pili , ribosomes and circular DNA

(ii) Understand the function of the structures listed in (i)

3.6 Recognizing Organelles

Be able to recognise the organelles in 3.3 from electron microscope (EM) images

3.7 Microscopy

(i) Know how magnification and resolution can be achieved using light and electron microscopy

(ii) Understand the importance of staining specimens in microscopy

3.8 CORE PRACTICAL 5

(i) Use a light microscope to make observations and labelled drawings of suitable animal cells

(ii) Use a graticule with a microscope to make measurements and understand the concept of scale

3.9 Gene Location and Linkage

(i) Know that a locus is the location of genes on a chromosome

(ii) Understand the linkage of genes on a chromosome

3.11 Specialisation of Mammalian Gametes

Understand how mammalian gametes are specialised for their functions (including the acrosome in sperm and the zona pellucida in the egg cell )

3.12 Fertilisation in Mammals

Know the process of fertilisation in mammals, including the acrosome reaction , the cortical reaction and the fusion of nuclei

3.13 Fertilisation in Flowering Plants

Know the process of fertilisation in flowering plants, starting with the growth of a pollen tube and ending with the fusion of nuclei

RECOMMENDED ADDITIONAL PRACTICAL

Investigate factors affecting the growth of pollen tubes.

3.14 Role of Mitosis and the Cell Cycle

Understand the role of mitosis and the cell cycle in producing genetically identical daughter cells for growth and asexual reproduction

3.10 Role of Meiosis

Understand the role of meiosis in ensuring genetic variation through the production of non-identical gametes as a consequence of independent assortment of chromosomes in metaphase I and crossing over of alleles between chromatids in prophase I

Names of the stages of prophase are not required.

3.15 CORE PRACTICAL 6

Prepare and stain a root tip squash to observe the stages of mitosis.

3.16 Calculating Mitotic Indices

Be able to calculate mitotic indices

3.19 Post-Transcriptional Changes

Understand how one gene can give rise to more than one protein through post-transcriptional changes to messenger RNA (mRNA)

3.17 Stem Cells

(i) Understand what is meant by the terms stem cell , pluripotent , totipotent , morula and blastocyst

(ii) Be able to discuss the ways in which society uses scientific knowledge to make decisions about the use of stem cells in medical therapies

3.18 Cell Specialisation

Understand how cells become specialised through differential gene expression , producing active mRNA , leading to the synthesis of proteins which, in turn, control cell processes or determine cell structure in animals and plants

3.20 Phenotype and Genotype

(i) Understand how phenotype is the result of an interaction between genotype and the environment

(ii) Know how epigenetic modification , including DNA methylation and histone modification , can alter the activation of certain genes

(iii) Understand how epigenetic modifications can be passed on following cell division

3.21 Polygenic Inheritance and Continuous Variation

Understand how some phenotypes are affected by multiple alleles for the same gene , or by polygenic inheritance , as well as the environment , and how polygenic inheritance can give rise to phenotypes that show continuous variation