Biology Flashcards
what are carbohydrates also known as?
sugars and are molecules made up of carbon, hydrogen, and oxygen
CHO
what does catabolized mean? what does it create
broken down to create energy molecules such as adenosine triphosphate (ATP) or nicotinamide adenine dinucleotide (NAD’)
what is ATP and NAD’?
ATP provides a source of energy
NAD’ provides a source of electrons to drive cellular processes
what is the monomer of carbohydrates?
-example?
polymers of carbohydrates? Example?
-monosaccharide
-glucose
-polysaccharide
-starch which is used to store excess sugar
what type of carbohydrate is cellulose and what is it
-polysaccharide and is a support fiber responsible in part for the strength of plants
what are lipids composed ?
-what do they contain?
-composed of hydrogen and carbon, small percentage of oxygen
-the contain a head and tail
the head of the lipid is?
-the tail of the lipid is?
-usually phosphate or glycerol and is hydrophilic and polar. points outwards
-the tail is a hydrocarbon chain and is hydrophobic and nonpolar. points inwards
what does saturation describe?
the number of double bonds in the tail of the lipid. more double means more unsaturated (fats)
functions of proteins
-act as catalysts, transports molecules across membranes, facilitate DNA replication and regulate the cell cycle including mitosis and meiosis
proteins are composed of?
-what the three parts to it?
-amino acids
-amino group
-carboxyl group
-R group
how many amino acids are used to produce protein?
-22
nuclei acids are?
store all info necessary to produce proteins. found in DNA and RNA
-made up of nucleotides
what are nucleotides composed of?
5-carbon sugar, a phosphate group, and a nitrogenous base (A,T,G,C)
order of protein units
nucleotides to nuclei acids to proteins to chromosomes
what are the nucleotides of DNA
-adenine to thymine
-cytosine to guanine
purines are?
pyrimidines are?
adenine and guanine
-thymine and cytosine
on the double helix whats on the outside and inside?
sugar on the outside and nitrogenous base on the inside
what’s replaced for RNA?
-thymine by uracil so AU
-is also a single strand and contains ribose
DNA vs RNA
-DNA contains double helix and RNA is only one strand
-RNA contains ribosomes, DNA contains deoxyribose
-RNA in uracil and thymine in DNA
what prime does DNA start with?
5’ to 3’
what is histones?
proteins which organize DNA and this DNA is known as chromatin. To form nucleosomes, DNA is wrapped around histones
during interphase, what happens to chromatin?
during mitosis?
-chromatin is arranged loosely to have access to DNA
-DNA is tightly packaged into unit cells called chromosomes
when DNA has replicated, what happens?
the chromosome is composed of two chromatids joined together at the centromere
what is a diploid
somatic cell meaning it has two sets of homologous chromosomes one from each parent
what is a haploid?
-cells with one set of chromosomes
what does helicase do?
it is an enzyme that unwinds DNA into two separate strands
what is the leading strand?
what is the lagging strand?
-leading can only be read by DNA in the 3’ to 5’ direction
-the lagging strand runs to 5’ to 3’ and has to be synthesized piece by piece in chunks called Okazaki fragments
every time a full chromosome is replicated, what happens?
a very small part of the DNA is lost at the end, this piece is called a telomere which is usually noncoding. this is why DNA replication must come to an end eventually
what is DNA polymerase responsible for?
for synthesizing Okazaki fragment. DNA polymerase III is the primary replication of the 5’ to 3’ strand
what is DNA ligase responsible for?
fixes small breaks in the DNA strand is used to seal the finished DNA strands
DNA telomerase is responsible for?
-lengthens the telomeres at the end of each strand of DNA, allowing it to be copied additional times
how many possible codons are there?
- there are three stop codons which instruct the ribosome to stop processing the mRNA
explain transcription
it is the process of making messenger RNA (mRNA) from a DNA strand. the DNA first unwound then RNA polymerase makes a complementary transcript of the DNA sequence called mRNA
explain translation
process which converts the mRNA transcript into a useable protein. occurs in the ribosome which lines up the mRNA so it can bind to tRNA (transfer RNA). each tRNA includes an amino acid and an anticodon and a bond is formed between the growing amino acid strand and the new amino acid brought by tRNA
what is an anticodon?
included in tRNA, this matches to the complementary codon on the mRNA
what is a release factor?
it is a protein (which is activated by a stop codon in the ribosomes) which binds to ribosomes and will split a part after this release factor binds and creates a newly formed amino acids chain
what is a point mutation
a single base in the sequence of a gene changes permanenetly through substitution, deletion, or insertion
base substitution?
a mutation in which one or more bases in sequence changes
whats insertion?
occurs when one base or a few bases is added to the sequence
what is deletion?
when one nucleotide or a few is lost from the sequence
frameshift mutation
when DNA nucleotides are removed or added and result in how the gene is read by RNA polymerase and ribosomes
chromosome invasion
two breaks occur in chromosomes and fragment that breaks away flips around and reattaches
what is an operon?
what is a promoter?
what is an operator?
-proteins that are produced from a set of genes
-is included in operons, and initiates transcription
-an enzyme can bind to this and regulate transcription and the protein coding sequence
what are alleles?
multiple versions of the same gene and account for variation in a population
what is homozygous?
what is heterozygous?
-two genes that are identical (RR or rr)
-two genes that are different, genes do not blend and act separately, one often being completely or partially suppressed (Rr)
genotype vs phenotype
genotype is complete genetic code and phenotype is observable characteristics
what is epistasis?
same genotypes expressed differently based on environmental factors or presence of other genes
the law of segregation
-states that genes come in allele pairs, if the organism is diploid, and that each parent can pass only a single allele down to its child. each individual has a pair of alleles for each gene: one from mom and one from dad. also states that alleles must separate during ,meiosis so that only one is given to each gamete
law of independence assortment
state that genes responsible for different traits are passed on independently, mom is tall with brown hair, may pass down tallness but not brown hair
law of dominance
states that some alleles are dominant and some are recessive. dominant mask the behavior of the recessive
when does gene linkage occur?
when genes that are situated close together on a chromosome and thus are more likely to be inherited together
females vs males chromosomes
females have two X chromosomes and carries two alleles which means the dominant allele will express itself for X linked traits.
males have both an X and Y chromosome and only one allele for every X gene, trait will be expressed whether it’s dominant or recessive
what’s crossing over and when does it occur?
-the process of meiosis also introduces genetic variation during crossing over which occurs in prophase I when homologous chromosomes pair along their lengths and creates a new chromatid
