Test Revision Flashcards
What does DNA stand for?
deoxyribonucleic acid
In a diploid cell there are how many pairs of sex chromosomes?
One
What is a gene?
A section of DNA that codes for a specific protein.
What is the structure of DNA?
A double helix.
What is a chromosome?
Threads of a DNA molecule wrapped in a protein coat.
Are all genes expressed at birth?
No
Can the environment affect if genes are expressed?
Yes
How many chromosomes and chromosome pairs in human cells?
46 chromosomes, 23 chromosome pairs
How much genetic material is from each parent?
50% from each
Order these largest to smallest, Cells, Chromosomes, Nucleus, DNA, Genes
Cells, Nucleus, Chromosomes, DNA, Genes
Germ cell
A parent cell that undergoes meiosis
Cellular proliferation
The growth and repair of cells
Where do gender determinate chromosomes come from?
Sperm
What role do proteins play in the body?
Proteins have structural or functional roles.
What are the two main types of cell division?
Mitosis and Meoisis
Similarities between Mitosis and Meiosis
For both types every chromosome needs to be copied to then put one new copy in each of the new cells created. They both go through similar cycles of PMAT and both start with parent cells.
What is mitosis?
Cell division producing two daughter cells that are identical to the parent cell.
Differences between Mitosis and Meiosis
Mitosis - daughter cells are diploid and have 46 chromosomes, meiosis - daughter cells are haploid and have 23 chromosomes. Mitosis 2 identical daughter cells are formed. Meoisis 4 different daughter cells are formed. Mitosis is for cell growth and repair. Meoisis produces unique sex cells for genetic diversity.
Different cell types for Mitosis and Meiosis
Mitosis produces somatic cells (diploid) and Meiosis produces sex cells (haploid)
What is meiosis?
Meiosis is cell division that produces gametes, which have half the number of chromosomes as the parent cell.
What is a gamete?
Sperm/egg.
What does Simple Inheritance mean?
When the appearance or absence of a trait is controlled by a single gene.
What is genetic code?
The sequence of bases in a gene providing instructions for the production of RNA molecules.
What are RNA molecules made from?
The complimentary bases of the gene.
What are ribosomes and what do they do?
Ribosomes are the organelle that make proteins. It reads 3 bases at a time (a codon).
What is a permutation?
An ordered group of objects.
Permutation Formula
Permutation=Number of Letters to the power of the number of positions
What are alleles?
Different versions of the same gene. Part of homologous chromosome, I get one from mum, one from dad.
What is a Homologous pair?
A pair of chromosomes that are similar by shape and organisation
What is a mutation?
A small change in a gene that is passed down to the next generation.
What are the types of mutation?
Point Mutation, Deletion Mutation, Insertion Mutation.
What is Point Mutation?
One base is incorrectly copied.
What is Deletion Mutation?
Rest of the sequence is correct, but one was deleted.
What is Insertion Mutation?
An extra base is inserted into the sequence.
What has to happen for recessive genes to occur in offspring?
Both parents must be carriers of the recessive gene.
What are the phases in the cell cycle?
Interphase, prophase, metaphase, anaphase, telophase.
What happens in interphase?
DNA is in loose strands and the cell replicates its DNA.
What happens in prophase?
The nuclear membrane begins to break down and the chromosomes condense.
What happens in metaphase?
The chromosomes line up in the cell’s equator.
What happens in anaphase?
The chromatids separate and pulled towards opposite poles by the spindle fibers.
What happens in telophase?
Two nuclei form, each with their own identical set of DNA.
What is cytokinesis?
The physical process where the cytoplasms separate completely forming two distinct cells.
Germ cell/parent cell are the only cells that can…
Undergo both mitosis and meiosis
What is a Genotype?
The combination of genes.
What is a Phenotype?
The physical characteristics of genes.
Homozygous vs Heterozygous.
Homozygous is where you have two gene types that are the same, whereas heterozygous is where one gene type is different to the other.
Genotype vs Phenotype
A set of genes an organism carries. Phenotype is observable characteristics caused by genes.
What is sex linked inheritance?
Sex linked inheritance refers to how genes for traits are found on a sex chromosome, making genetic traits be inherited differently for women and men.
What is crossing over?
This occurs in prophase I, where homologous chromosomes exchange segments of their genetic material.
What is a karyotype?
An image of someones complete set of chromosomes.
Telophase in Mitosis vs Telophase in Meiosis
Telophase in mitosis forms two genetically identical nuclei. Whereas in meiosis, two genetically different nuclei are formed because of the crossing over in prophase 1.
