Pages in this set

Page 1

Preview of page 1
Sameer Biology
Jahabarali


Unit 5 Module 1 Cellular control







Protein synthesis


A gene is a length of DNA that codes for one or more
polypeptides, including enzymes. It occupies a specific region
(locus) within a chromosome (a long chain of supercoiled
nucleotide base pairs, associated with histone proteins), within the…

Page 2

Preview of page 2
Sameer Biology
Jahabarali


Unit 5 Module 1 Cellular control




Transcription is the first stage of protein synthesis
whereby a genetic code is copied to mRNA (free
activated nucleotide, with two extra phosphate
group) roaming the nucleoplasm and is transported
to the ribosome, found in the cytoplasm.

A gene dips in…

Page 3

Preview of page 3
Sameer Biology
Jahabarali


Unit 5 Module 1 Cellular control




Mutation is caused by mutagens which causes a change in the sequence of nucleotides in the DNA. A
change in the base pair sequence of a gene produces a different allele (different version of the same gene)
which can be caused…

Page 4

Preview of page 4
Sameer Biology
Jahabarali


Unit 5 Module 1 Cellular control




Polypeptides are not synthesised as the gene is not translated without the mRNA

When lactose availability is high:

Inducer molecule (Lactose) binds to the repressor
protein, causing the tertiary structure to be altered.
The repressor disassociates from the operator region
Promoter…

Page 5

Preview of page 5
Sameer Biology
Jahabarali


Unit 5 Module 1 Cellular control





Apoptosis is programmed cell death that occurs in multicellular organism. After 50 mitotic cell division
(Hayflick constant) a cell undergoes this quick process whereby:

Enzymes breakdown the cytoskeleton
The cytoplasm becomes dense and organelles gets tightly packed
The cell membrane forms…

Page 6

Preview of page 6
Sameer Biology
Jahabarali


Unit 5 Module 1 Cellular control





Meiosis
Sexual reproduction is achieved by meiosis to produce gametes (haploid cells, with half the chromosomes).
Gametes fuse together at fertilisation to produce a zygote (cell with new genetic code). Meiosis takes place
in two separate divisions, Meiosis I and Meiosis…

Page 7

Preview of page 7
Sameer Biology
Jahabarali


Unit 5 Module 1 Cellular control





Meiosis II

Prophase II

Nuclear envelope breaks down again (most animals)
Nucleolus disappears, chromatin condenses and spindle forms

Metaphase II

Chromosomes line-up randomly in the equator of the spindle and attaches
to the spindle fibres at the centromere

Anaphase II

The…

Page 8

Preview of page 8
Sameer Biology
Jahabarali


Unit 5 Module 1 Cellular control





Mutation- DNA mutation occurs during Interphase, when DNA replicates or Chromosome Mutation
occurs. (not specific to meiosis)



The genotype is the entire genetic makeup of an organism that is made up of two alleles of the same gene.
The alleles can…

Page 9

Preview of page 9
Sameer Biology
Jahabarali


Unit 5 Module 1 Cellular control





development of muscle weakness and early death by the 20s.

XD Y


XD XD XD XD Y


Xd XD Xd Xd Y




CR CR


CW CR CW CR CW


CW CR CW CR CW


CR CW


CR CR CR CW CR…

Page 10

Preview of page 10
Sameer Biology
Jahabarali


Unit 5 Module 1 Cellular control




Antagonistic interaction occurs when, the epistatic allele in the first locus, prevents the hypostatic allele in
the second locus from being expressed. It is not inherited and it decreases phenotypic variation. Epistasis of
homozygous alleles may be:

Recessive (e.g. inheritance of…

Comments

sara

Your work is amazing, its really helpful. Have you done responding to the environment biology module 4?

Similar Biology resources:

See all Biology resources »See all resources »