Early start and Ch 1 1st cells

Question 1

Covalent bond

Answer 1

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

Question 2

Polar molecule

Answer 2

a molecule such as water with an uneven distribution of charges in different regions of the molecule

Question 3

Phenotype

Answer 3

An organisms observable characteristics or traits

Question 4

Alleles

Answer 4

Alternative forms of a gene that occupies a specific position (locus) on a chromosome.

Question 5

Genotype

Answer 5

The genetic make up of an organism

Question 6

Heterozygote

Answer 6

A eukaryotic individual has two different forms of a gene which determines a trait

Question 7

Homozygote

Answer 7

A eukaryotic individual that has two identical forms of a gene which determines a particular trait

Question 8

Catabolic reactions

Answer 8

Biochemical reactions that breakdown nutrients

Question 9

Anabolic reactions

Answer 9

Biochemical reactions that synthesise new macro molecules from smaller components

Question 10

Photosynthesis

Answer 10

6 H2O +6 CO2 = C6H12O6+602 Is equation for?

Question 11

Aerobic respiration

Answer 11

C6H1206+ 602 = 6 H2O +6 CO2 Is equation for?

Question 12

Homozygous

Answer 12

Same alleles for a certain gene

Question 13

Heterozygous

Answer 13

Different alleles for a certain gene

Question 14

Dominant

Answer 14

The allele observed in the phenotype when present in a heterozygote

Question 15

Recessive

Answer 15

The allele not observed when present in a heterozygote – only observed when two copies are present

Question 16

Recombination

Answer 16

Exchange of genetic material between paired chromosomes in meiosis 1 - crossing over

Question 17

Valency

Answer 17

No of bonds atom can form within a molecule

Question 18

Macromolecules

Answer 18

Very large complex molecules made up of smaller components, such as a protein formed from amino acids.

Question 19

Proteins

Answer 19

Large macromolecules consisting of one or more polypeptide chains built from amino acids.

Question 20

Hydrogen bonds

Answer 20

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).

Question 21

Monomer

Answer 21

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.

Question 22

Polymer

Answer 22

A large molecule formed by the linking together of many smaller repeating units known as monomers.

Question 23

Peptide

Answer 23

Short chains (polymers) of several amino acids.

Question 24

Polypeptide

Answer 24

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.

Question 25

Genome

Answer 25

The total genetic material within a cell or organism, usually consisting of DNA (some viruses have RNA genomes).

Question 26

Genes

Answer 26

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.

Question 27

Ribosome

Answer 27

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.

Question 28

DNA replication

Answer 28

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.

Question 29

Genetic variation

Answer 29

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.

Question 30

Liposomes

Answer 30

A hollow, spherical fluid-filled bilayer structure that assembles spontaneously in an aqueous medium from two-tailed amphipathic lipids (those characteristic of biological membranes)

Question 31

Metabolism

Answer 31

The entirety of the biochemical processes that are necessary to maintain life and allow organisms to grow, reproduce and respond to their environment.

Question 32

Glycolysis

Answer 32

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.

Question 33

Genetic code

Answer 33

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).

Question 34

Taxonomy

Answer 34

The science of describing, classifying and naming organisms based on their shared characteristics or phylogenic relationships.

Question 35

Phylogeny

Answer 35

The family tree of a group of organisms which describes their evolutionary history.

Question 36

Prokaryotes

Answer 36

The mainly single-celled organisms in the domains Bacteria and Archae.

Question 37

Nucleotide

Answer 37

The region in the cytoplasm of a prokaryotic cell that contains the circular genomic DNA molecule.

Question 38

Cytosol

Answer 38

The liquid component of the cytoplasm surrounding the organelles and other cytoplasmic structures.

Question 39

Cytoplasm

Answer 39

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.

Question 40

Capsule

Answer 40

A protective slimy outer layer present in some bacterial cells.

Question 41

Adenosine triphosphate (ATP)

Answer 41

Universal form of chemical energy

Question 42

Endosymbiotic theory

Answer 42

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.

Question 43

Flagella

Answer 43

(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.

Question 44

Totipotent

Answer 44

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

Question 45

Protist

Answer 45

Unicellular organism of diverse group of eukaryotes

Question 46

Gene expression

Answer 46

The process by which information from a gene is used to synthesise a functional gene product; a protein or an RNA.

Question 47

Symbionts

Answer 47

Organisms that live together for mutual benefit

Question 48

Natural selection

Answer 48

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.

Question 49

Identify four of the general characteristics that identify a bacterium as a living organism rather than nonliving object

Answer 49

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

Question 50

Organic molecules

Answer 50

Lipids DNA and amino acids are going organic molecules; they contain carbon atoms linked together. Water is an inorganic molecule.

Question 51

Which term describes the general type of cellular reaction in which energy is used to build molecules from smaller units?

Answer 51

Anabolic

Question 52

How can natural selection lead to increases or decreases in the frequencies of particular gene variance (alleles) in a population of organisms?

Answer 52

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.