bio exam yr11

nucleotide and three parts

hemizygous

on the x sex chromosome of the male

pure breeding

homozygous

complementary base pairing

base in one strand can from a specific hydrogen bonds with another base in the opposite strand across from it

rna

• ribonucleic acid

• single stranded sugar phosphate

• uracil

dna

• deoxyribonucleic acid

• thymine

• double stranded sugar phosphate

transcription

• DNA is copied onto a strand of mRNA

• RNA polymerases, which link nucleotides to form an RNA strand

• initiation, elongation, and termination

translation

• The code on mRNA is "read" and used to create a protein

• tRNAs bind to mRNAs inside of a protein-and-RNA structure called the ribosome

initiation

• RNA polymerase binds to a sequence of DNA called the promoter

• RNA polymerase separates the DNA strands

elongation

• strand of DNA, the template strand, acts as a template for RNA polymerase

• polymerase builds an RNA molecule out of complementary nucleotides, making a chain that grows from 5' to 3'

• contains the base uracil (U) instead of thymine (T)

termination

• signal that the RNA transcript is complete

• Once transcribed, the transcript to be released from the RNA polymerase

translation steps

• small ribosomal sub-unit attaches to a specific nucleotide sequence on the mRNA strand

• ‘upstream’ the initiation codon (AUG) where translation will start.

• initiator tRNA, carrying methionine, attaches to the initiator codon.

• large ribosomal sub-unit binds to complete the protein-synthesizing complex.

• amino acids are added one by one by tRNAs as the ribosome moves along the mRNA.

• release factor binds to the stop

  codon and hydrolyzes the completed

  polypeptide from the tRNA, releasing

  the polypeptide from the ribosome.

mrna

• is a type of single-stranded RNA involved in protein synthesis. mRNA is made from a DNA template during the process of transcription.

trna

responsible for matching amino acids with the appropriate codons in mRNA. molecule has two distinct ends, one of which binds to a specific amino acid, and the other which binds to the corresponding mRNA codon.

triplets

a three-nucleotide sequence that is unique to an amino acid

codons

DNA or RNA sequence of three nucleotides that forms a unit of genomic information encoding a particular amino acid or signaling the termination of protein synthesis (stop signals)

anti codons

a trinucleotide sequence located at one end of a transfer RNA (tRNA) molecule

rna processing

5' cap is added to the beginning of the RNA transcript, and a 3' poly-A tail is added to the end.

splicing, some sections of the RNA transcript (introns) are removed, and the remaining sections (exons) are stuck back together

Capping at the 5' end

Addition of a polyA tail at the 3' end. and

Splicing to remove introns

alternative splicing

one pre-mRNA may be spliced in either of two (or sometimes many more than two!) different ways

Deoxyribonucleic acid (DNA)

a double-stranded nucleic acid chain made up of nucleotides.

Nucleic acid

macromolecules that includes DNA and RNA

Nucleotide

the monomer unit of nucleic acids.

Gene

A segment of DNA on a chromosome that codes for a specific protein

Genome

the complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes

Allele

An alternative form of a gene.

Locus

Location of a gene on a chromosome

Phenotype

observable characteristics of an individual resulting from the interaction of its genotype with the environment.

Genotype

An organism's genetic makeup, or allele combinations.

Haploid

having a single set of unpaired chromosomes

Diploid

containing two complete sets of chromosomes, one from each parent.

Chromosomes

threadlike structures made of DNA molecules that contain the genes

somatic cells

any cell of a living organism other than the reproductive cells.

Telomeres

DNA at the tips of chromosomes

Centromere

Region of a chromosome where the two sister chromatids attach

Chromatid

one of two identical "sister" parts of a duplicated chromosome

homologous chromosomes

Chromosomes that have the same sequence of genes, that have the same structure, and that pair during meiosis.

Karyotype

A display of the chromosome pairs of a cell arranged by size and shape.

Autosomes

Any chromosome that is not a sex chromosome

sex chromosomes

One of the 23 pairs of chromosomes in the human, contains genes that will determine the sex of the individual.

Aneuploidy

the presence of an abnormal number of chromosomes in a cell

Polyploidy

condition in which an organism has extra sets of chromosomes

Monosomy

Chromosomal abnormality consisting of the absence of one chromosome from the normal diploid number

Trisomy

a condition in which an extra copy of a chromosome is present in the cell nuclei, causing developmental abnormalities.

Meiosis

a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes and plant spores.

Gametes

reproductive cells

Zygote

a diploid cell resulting from the fusion of two haploid gametes; a fertilized ovum.

crossing over

Process in which homologous chromosomes exchange portions of their chromatids during meiosis.

independent assortment

the random distribution of the pairs of genes on different chromosomes to the gametes

Homozygous

Having two identical alleles for a particular gene

Heterozygous

having two different alleles for a particular gene

dominant allele

An allele whose trait always shows up in the organism when the allele is present.

recessive allele

An allele that is masked when a dominant allele is present

Carrier

A person whose genotype includes a gene that is not expressed in the phenotype.

Codominance

situation in which both alleles of a gene contribute to the phenotype of the organism

incomplete dominance

A pattern of inheritance in which two alleles, inherited from the parents, are neither dominant nor recessive. The resulting offspring have a phenotype that is a blending of the parental traits.

Codominance example

AB blood type

incomplete dominance example

red flower + white flower = pink flower

sex-linked gene

gene located on a sex chromosome

X-linked

referring to a gene located on the X chromosome

monohybrid cross

A cross between two individuals, concentrating on only one trait

Punnet Square

a method of predicting the genotypes and phenotypes of offspring in genetic crosses

test cross

the crossing of an individual of unknown genotype with a homozygous recessive individual to determine the unknown genotype

Pedigree

A diagram that shows the occurrence of a genetic trait in several generations of a family.

Population

A group of individuals that belong to the same species and live in the same area

gene pool

All the genes, including all the different alleles for each gene, that are present in a population at any one time

genetic diversity

a measure of the genetic variation among individuals in a population

sexual reprodcution

reproduction in which two parents have offspring that have unique combinations of genes inherited from the gametes of the two parents.

asexual reproduction

involves one parent and produces offspring that are identical to the parent.

binary fission

A form of asexual reproduction in which one cell divides to form two identical cells.

Budding

Asexual reproduction in which a part of the parent organism pinches off and forms a new organism

Fragmentation

A means of asexual reproduction whereby a single parent breaks into parts that regenerate into whole new individuals.

parthenogenesis

Asexual reproduction in which females produce offspring from unfertilized eggs.

Advantages of asexual reproduction

1. no need mate; can live isolate

2. numerous offspring quickly

3. no energy needed for maintenance of reproductive structures

4. good with stable enviroment

somatic cell nuclear transfer

a cloning technique that involves substituting genetic material from an adult's cell for the nucleus of an egg

embryo splitting

a form of cloning that is accomplished by dividing a growing embryo into equal parts using a surgical procedure performed with the aid of a microscope

plant cuttings

in plant cloning, a leaf and stem are cut off a plane and then dipped in hormone powder to encourage rooting, and a new plant grows

plant grafting

the attachment of two individual plant stems together

structural adaptation

a physical feature of an organism's body having a specific function that contributes to the survival of the organism

physiological adaptation

a physical or chemical event that occurs within the body of an organism and enables survival

Ecosystem

A community of organisms and their abiotic environment

population size

the total number of individuals within a defined area at a given time

population density

Number of individuals per unit area

population distribution

how population is spread out in an area

Immingration

Moving into a population

carrying capacity

the largest population that an environment can support at any given time

Parasitism

A relationship between two organisms of different species where one benefits and the other is harmed

competition

A common demand by two or more organisms upon a limited supply of a resource; for example, food, water, light, space, mates, nesting sites.

integrity

encourages a full commitment to knowledge and understanding as well as the honest reporting of all sources of information and results

Justice

encourages fair consideration of competing claims, and ensures that there is no unfair burden on a particular group from an action

Beneficence

encourages the maximisation of benefits while minimising the risks and harms involved in taking a particular position or course of action

Non-maleficence

discourages causing harm - or when harm is unavoidable, ensuring that the harm is not disproportionate to the benefits from any position or course of action

respect

encourages the acknowledgment of the intrinsic value of living things, and considers the welfare, beliefs, customs, and cultural heritage of both the individual and the collective

cell

• The basic unit of life (living things)

Cell Theory

• all living things are composed of cells, cells are the basic units of life and new cells are produced from existing cells

Prokaryote

• no nucleus

• no membrane bound organelles

• small and simple

• cell walls

• unicellular

• bacteria

• linear dna

eukaryote

• nucleus

• membrane bound organelles

• cilia

• uni or multicellular

Cytoskeleton

• helps cell keep its shape

• involved in movement

cytoplasm

• jelly fluid in cell which organelles sit in

cytosol

• fluid of cytoplasm

chloroplast

• photosynthesis

• plants only

• chlorophyll