Early start and Ch 1 1st cells Flashcards
Covalent bond
the sharing of a pair of valence electrons by two atoms. very strong bond, hard to break. two or more atoms held together by covalent bonds constitue a molecule a bond in which electrons are shared equally is a nonpolar ovalent bond a bond in which electrons are not shared equally is a polar covalent examples: hydrogen, oxygen, water, methane
Polar molecule
a molecule such as water with an uneven distribution of charges in different regions of the molecule
Phenotype
An organisms observable characteristics or traits
Alleles
Alternative forms of a gene that occupies a specific position (locus) on a chromosome.
Genotype
The genetic make up of an organism
Heterozygote
A eukaryotic individual has two different forms of a gene which determines a trait
Homozygote
A eukaryotic individual that has two identical forms of a gene which determines a particular trait
Catabolic reactions
Biochemical reactions that breakdown nutrients
Anabolic reactions
Biochemical reactions that synthesise new macro molecules from smaller components
Photosynthesis
6 H2O +6 CO2 = C6H12O6+602 Is equation for?
Aerobic respiration
C6H1206+ 602 = 6 H2O +6 CO2 Is equation for?
Homozygous
Same alleles for a certain gene
Heterozygous
Different alleles for a certain gene
Dominant
The allele observed in the phenotype when present in a heterozygote
Recessive
The allele not observed when present in a heterozygote – only observed when two copies are present
Recombination
Exchange of genetic material between paired chromosomes in meiosis 1 - crossing over
Valency
No of bonds atom can form within a molecule
Macromolecules
Very large complex molecules made up of smaller components, such as a protein formed from amino acids.
Proteins
Large macromolecules consisting of one or more polypeptide chains built from amino acids.
Hydrogen bonds
Relatively weak chemical bonds formed between slightly positively charged hydrogen atoms (which are involved in strong covalent bonds with strongly electron-attracting atoms like oxygen or nitrogen), and strongly electron-attracting (and therefore slightly negatively charged) atoms in other molecules (or other chemical groups within the same molecule).
Monomer
A molecule that, under the correct conditions, can link together with others to form larger molecules called polymers. A monomer must be capable of forming two or more bonds to other monomers.
Polymer
A large molecule formed by the linking together of many smaller repeating units known as monomers.
Peptide
Short chains (polymers) of several amino acids.
Polypeptide
A sequence of amino acids joined together in a linear chain (polymer). Very small chains consisting of only a few amino acids are known as peptides.
Genome
The total genetic material within a cell or organism, usually consisting of DNA (some viruses have RNA genomes).
Genes
Segments of nucleic acid that can be considered as units of inheritance. Genes consist of coding sequences, which specify the structure of the gene product, and regulatory sequences which control when and where the gene is expressed.
Ribosome
A particle composed of RNA and protein that is found in large numbers in all cells and is essential for protein synthesis. Using messenger RNA (mRNA) as a template, the ribosome pairs each mRNA codon with a transfer RNA (tRNA) carrying an appropriate amino acid to assemble a polypeptide chain.
DNA replication
The synthesis of an exact copy of a DNA molecule. Each of the polynucleotide strands of the double-stranded DNA can act as a template strand on which a new complementary strand is synthesised. Two identical double helices are thereby produced.
Genetic variation
Variation between the genomes of individuals brought about by the introduction of new gene combinations during reproduction (resulting, for example, from recombination between chromosomes) or gene mutation resulting from rearrangements and errors in the sequence of nucleotides during DNA replication.
Liposomes
A hollow, spherical fluid-filled bilayer structure that assembles spontaneously in an aqueous medium from two-tailed amphipathic lipids (those characteristic of biological membranes)
Metabolism
The entirety of the biochemical processes that are necessary to maintain life and allow organisms to grow, reproduce and respond to their environment.
Glycolysis
The first, anaerobic stage of glucose oxidation, in which glucose is converted into pyruvate or lactate, releasing small amounts of usable chemical energy in the form of high energy molecules like ATP. It takes place in the cytosol.
Genetic code
The set of rules that specify the correspondence between the nucleotide triplets (codons) in DNA or RNA and the amino acids in a polypeptide (protein) gene product. There are 64 triplet codons in the so-called ‘universal’ genetic code; not all of these code for particular amino acids since three of them are stop codons. The genetic code is slightly different in some species and in the DNA of organelles (e.g mitochondrial).
Taxonomy
The science of describing, classifying and naming organisms based on their shared characteristics or phylogenic relationships.
Phylogeny
The family tree of a group of organisms which describes their evolutionary history.
Prokaryotes
The mainly single-celled organisms in the domains Bacteria and Archae.
Nucleotide
The region in the cytoplasm of a prokaryotic cell that contains the circular genomic DNA molecule.
Cytosol
The liquid component of the cytoplasm surrounding the organelles and other cytoplasmic structures.
Cytoplasm
In eukaryotes, the contents of the cell excluding the nucleus, but including the other organelles. In prokaryotes there are no organelles, so DNA, RNA, ribosomes, etc. are free in the cytoplasm.
Capsule
A protective slimy outer layer present in some bacterial cells.
Adenosine triphosphate (ATP)
Universal form of chemical energy
Endosymbiotic theory
A theory that eukaryotic organelles including mitochondria and plastids (such as the chloroplasts of green plants) originated as free-living prokaryotes that entered other cells and became established as endosymbionts, eventually losing their independence to become an essential part of the larger cell.
Flagella
(Sing. flagellum) Long appendages that protrude from the surface of some cells and are used for movement, or in some cases for signalling changes in the environment to the cell’s interior. Bacterial flagella are protein structures that protrude from the cell membrane and produce movement by rotation, while eukaryotic flagella are enclosed by a continuation of the cell membrane and have a whip-like motion.
Totipotent
A cell which has the potential to form an entire organism. Able to change and become another type of cell as required.
E.g. embryo stem cells are totipotent
Protist
Unicellular organism of diverse group of eukaryotes
Gene expression
The process by which information from a gene is used to synthesise a functional gene product; a protein or an RNA.
Symbionts
Organisms that live together for mutual benefit
Natural selection
The process which ensures that a variant (phenotype) that confers an advantage on an individual in terms of survival and reproduction, becomes more frequent in a population.
Identify four of the general characteristics that identify a bacterium as a living organism rather than nonliving object
Composed by an organised sale bound by a cell membrane
Can grow
Can reproduce
Has a heritable genetic code using 4 nucleotides
Can transform source of external energy (e.g. breakdown and nutrients to release chemical energy) and use it to drive cellular processes such as synthesis of my molecules including proteins (metabolism)
Ability to respond and adapt the environment
Ability to maintain a constant internal environment
Organic molecules
Lipids DNA and amino acids are going organic molecules; they contain carbon atoms linked together. Water is an inorganic molecule.
Which term describes the general type of cellular reaction in which energy is used to build molecules from smaller units?
Anabolic
How can natural selection lead to increases or decreases in the frequencies of particular gene variance (alleles) in a population of organisms?
Individuals with advantageous characteristics have a greater chance of surviving in the struggle for existence and of producing many offspring (often referred to as fitness). The characteristics of individuals are inherited, so the alien is carried by the fittest individuals will increase in frequency in the population, while those of the individual selected against a decrease in frequency.
