B6 - Inheritance, Variation and Evolution

Define haploid

one set of chromosomes

Define sexual reproduction

Reproduction requiring two gametes created by meiosis, producing genetically non-identical offspring

Define asexual reproduction

Reproduction involving a single parent producing genetically identical offspring using mitosis

Define diploid

two complete sets of chromosomes, one from each parent

What is mitosis used for?

Growth and repair of tissues and production of new cells as replacements

Define meiosis

A type of cell division that produces gametes with 23 chromosomes each

What can be said about meiosis genetically?

Produces genetically non-identical offspring

Are gametes haploid or diploid?

Haploid

Are somatic cells haploid or diploid?

Diploid

What two things cause genetic variation in meiosis?

Crossing over of DNA between chromosomes and independent variation of chromosomes

Define genome

The entire genetic material of an organism

Define genetic mutation

A change in base

What are the four types of genetic mutation?

Substitution,

Insertion,

Deletion,

Inversion

What is dangerous about insertion and deletion mutations that aren't done in multiples of three?

They cause a frame shift

What are the major causes of mutation?

Irradiation,

Cell division,

Carcinogens,

Age (cell division going wrong)

Define genotype

The alleles the organism has

Define phenotype

The physical appearance of an organism (expression of the alleles)

Define homozygous

Two identical alleles

Define heterozygous

Two different alleles

Define allele

Different forms of a gene

Define inherited disorder

Some part of a phenotype that malfunctions, passed down through the alleles of the parents

Is cystic fibrosis recessive or dominant?

recessive

Is polydactyly recessive or dominant?

dominant

Explain why a large amount of human insulin can be obtained by genetically engineering one bacterium.

Bacterium reproduce very quickly at optimum conditions

Describe how a bacterial cell can be genetically engineered to make human insulin

1. Insulin gene cut out of a human chromosome

2. Plasmid removed from bacterial cell by an enzyme

3. Insulin gene inserted into plasmid

4. New plasmid/insulin inserted into the bacterial cell

What organ of a pig used to be used to produce insulin?

Pancreas

Why are scientific names more useful than common names?

They are the same in every language

What is the outer casing of a DNA double helix known as?

a sugar-phosphate backbone

What codes for an amino acid?

one triplet of bases

what is a mutation?

change in DNA sequence

What are the three types of mutation?

substitution, insertion, deletion

Why is protein synthesis needed?

the specific sequence of bases have to be read by a ribosome which are outside of the nucleus and the DNA is too big to leave the nucleus

What is the name of the enzyme that binds to the template strand to create mRNA?

RNA polymerase

How do amino acids bond?

tRNA molecules bring amino acids and its anticodon binds to the complementary mRNA which detaches

Define gamete

sex cell

How many chromosomes are in each gamete?

23 chromosomes

What does asexual reproduction produce?

genetically identical offspring

How does asexual reproduction occur?

mitosis

What is plant sperm?

pollen

What type of cell is a gamete?

haploid

Name a disadvantage of sexual reproduction

time consuming, impossible for isolated populations

Are gametes haploid cells?

Yes

How many chromosomes does a human gamete have?

23

As a result of meiosis, how many cells are produced?

4 genetically non identical

Is cystic fibrosis dominant or recessive?

recessive

Is polydactyly dominant or recessive?

dominant

Who developed the three domain system?

Carl Woese

What are the three domains?

Archaea, Bacteria, Eukaryota

Which domain contains 4 kingdoms?

Eukaryota

Which domain have cells with nuclei?

Eukaryota

Define species

A group of organisms that can interbreed and produce fertile offspring

How many amino acids are used to create proteins?

20

Define gene

A small segment of DNA that codes for a protein

Define chromosome

Packaged DNA molecule

What is the end product of meiosis?

4 haploid cells (gametes)

What are the advantages of sexual reproduction?

Variation increases chance of survival, natural selection, can be used for selective breeding

What are the advantages of asexual reproduction?

Less energy used to find a mate, faster

What 23rd pair of chromosomes do males have?

XY

What 23rd pair of chromosomes do females have?

XX

What did Gregor Mendel call genes?

Hereditary units

What are the two types of variation?

Genetic and environmental

Define evolution

the natural selection of genetic changes that give rise to the phenotypes that are best suited to the environment

How can speciation be proved? (evolution into different species)

Population becomes reproductively isolated and cannot interbreed to create fertile offspring

Why was Darwin's theory not accepted?

religious beliefs, not understanding genes and mutations, lack of evidence

What was Lamarck's theory?

Changes that occur in an organism during its lifetime can be inherited

Define selective breeding

Artificial selection of plants/animals to breed so that the genes for advantageous characteristics remain in the population

What is the negative of selective breeding?

Reduction in the gene pool, inbreeding, lack of disease resistant alleles

What are the positives of genetic engineering?

Increased yield, more nutrients

What are the negatives of genetic engineering?

What is done in animal cloning to both the egg cell and the adult body cell?

Nucleus is removed (enucleated)

In adult cell cloning, what type of cell do you take from the organism you want to clone?

Adult body cell

What type of nucleus is used in adult cell cloning?

a diploid nucleus

What is a transgenic organism?

An organism that contains genes from another species

What is an explant?

A small piece of plant that can develop into a clone

What are the two methods of plant cloning?

Cuttings and tissue culture

What must be done to explants before they are placed in agar?

Sterilized to kill microorganisms

What do explants grow into before plantlets?

Calluses

Why are fossils used as evidence for evolution?

Fossils show us how species have changed over millions of years

What are three ways that fossils can form?

Gradual replacement by minerals, casts and impressions, preservation

Where may fossils be formed by preservation?

Peat bogs, amber, tar pits, glaciers

Why do we not have a complete fossil record?

Early life was soft bodied, destroyed by large geological events

When does isolation happen?

When a physical barrier separates a population of the same species

What two things cause speciation?

Isolation and natural selection

What causes antibiotic resistance (internally)?

random mutations in bacteria

Name a type of superbug

MRSA

Linnean Classification System with domain

Domain

Kingdom

Phylum

Class

Order

Family

Genus

Species

Who proposed the domain system?

Carl Woese

Give two things that are usually used as vectors in genetic engineering.

Bacterial plasmids and viruses

What name is given to small sections of DNA that code for particular proteins?

Genes

A chain of amino acids is called a

polypeptide

What undergoes sexual reproduction?

Animals and flowering plants

What are the gametes in flowering plants?

Pollen and egg cells

What gamete determines gender?

Sperm

Name 2 recessive conditions

Cystic fibrosis, sickle cell anemia

Name 2 dominant conditions

Polydactyly, Huntington's disease

How could you investigate if an organism showing a dominant trait is homozygous or heterozygous?

test cross

What molecule are genes made of?

DNA

What are the 5 kingdoms?

plants, animals, fungi, protists and prokaryotes

What is the name of the chain of amino acids?

polypeptide