Midterm1 Flashcards
Describe properties of living organisms
- Living organisms must be able to grow, metabolize substances, reproduce, and respond to external stimuli.
- Living organisms contain a common set of biological molecules, are composed of cells, and can maintain homeostasis and evolve
List the components of water and some of the properties that make it important in living organisms
- water consists of 1 oxygen and 2 hydrogen atoms
- Water is a good solvent in part because of its polarity and ability to form hydrogen bonds. Hydrogen bonding in water facilitates chemical reactions, promotes cohesion, and allows fo rheat absorption.
- The polarity of water also facilitates the dissolving of salts
- water has a neutral pH.
pH scale
measure of the relative percentages of ions in a solution and ranges from 0 (acidic or rich in hydrogen ions) to 14 (basic or rich in hydroxyl ions)
describe how structure affects chemical bonding
- Chemical bonding depends on an elements electron configuration. Electrons closer to the nucleus have less energy than thos that are farther away from the nucleus.
- Atoms that have space in their valence shell form chemical bonds.
hydrogen bond
weak attraction between hydrogen atoms and oxygen atoms in adjacent molecules
covalent bond
bond that forms when atoms share electrons. Tend to be strong bonds
Ionic bond
bonds formed between positively and negatively charge ions. Tend to be weaker bonds.
Importance of Carbon
life on earth based on carbon chemistry. the element carbon can bond with up to 4 other elements.
carbohydrates
function in energy storage and play structural roles. They can be single-unit monosaccharides or multiple unit polysaccharides with sugar monomers joined by covalent bonds
proteins
play structural, enzymatic, and transport roles in cells. composed of amino acid monomers joined by covalent bonds
lipids
partially or entirely hydrophobic and come in three forms. Fats are glycerol covalent bond to 3 fatty acids. fats store energy.
Phospholipid
lipid composed of glycerol, 2 fatty acids, and a phosphate group. important structure component of cell membranes
steroid
composed of 4 fused rings. Cholesterol is a steroid found in some animal cell membranes. Other steroids act as hormones
Nucleic acids
polymers of covalently bonded nucleotides, each composed of sugar, a phosphate, and a nitrogen containing base
prokaryotic cell
cell lacking a membrane bound nucleus
eukaryotic cells
cells containing membrane bound nucleus
mitochondria and chloroplasts
energy conversions
lysosomes
breakdown of macromolecules
ribosomes
sites for protein synthesis
smooth endoplasmic reticulum
synthesizes lipids
Golgi apparatus
sorts proteins and sends them to their cellular destination
centrioles
help cell divide
macromolecules in living organisms
carbohydrates, proteins, lipids, and nucleic acids
metabolism
all of the chemical processes that occur in the cell including breakdown, synthesis and excretion
homeostasis
roughly constant internal environment
enzymes
proteins that accelerate and help regulate all chemical reactions that build up and break down molecules inside the cell
amino acids
monomer subunits of proteins. 20 commonly occurring carbons, hydrogens, oxygens, nitrogen, and side groups
nucleotide
sugar, phosphate, nitrogen containing base
macronutrients
nutrients that are required in large amounts including water, carbohydrates, proteins, and fats
passive transports
includes simple diffusion and facilitated diffusion (diffusion through proteins) .
Always moves substance with their concentration gradient and does not require energy.
osmosis
diffusion of water across a membrane
active transport
active transport is an energy requiring process that requires proteins in cell membranes to move substances against their concentration gradient
endocytosis and exocytosis
large molecules move into and out of cells in membrane bound vesicles
enzyme
proteins speed up or catalyze the rate of biological reactions
substrate
chemicals that are metabolized by an enzyme catalyzed reaction are call the enzymes substrate
cellular respiration
series of metabolic reactions that converts the energy stored in chemical bonds of food into energy that cells can use while releasing waste product. glucose + oxygen = carbon dioxide + water
glycolysis
in cytesol part of cellular respiration 6 carbon sugar broken into 3 carbon pyruvic acid molecules
citric acid cycle
in the mitochondrial membrane. pyruvic acid is decarboxylated. remaining 2 carbon fragment moves to inner matrix of mitochondria and citric acid cycle strips them of carbon diozxid and electrons
electron transport chain
after glycolysis and citric acid cycle. electrons are carried by electron carrier (NADH) to inner mitochondrial membrane. added to series of proteins. oxygen pulls electrons toward itself. as electrons move down the chain the energy they release drives protons (H+) into intermembrane space. Once there, protons rush through the enzyme ATP synthase and produce ATP from ADP and phosphate
which of the following can neutralize dangerous free radicals within the body
antioxidants
what is the cause of 1/3 cancer deaths and 90% of lung cancer
smoking
the process by which cells of a malignant tumor can break and start new cancer at a distant location
metastasis
tumors that stay in one place and don’t affect surrounding tissues
benign
which of the following is not a known carcinogen
*the following are carcinogens
tobacco use, high fat/low fiber diet, lack of exercise, obesity, excess alcohol consumption, and increasing age
sister chromatids
replicated copy of chromosomes paired are called sister chromatids. each composed of one dna molecule and attached toward the middle and centromere.
DNA polymerase
moves along length of unwound dna helix and helps bind nucleotides to eachother on newly formed daughter strant.
mitosis
asexual division that produces daughter nuclei that are exact copies of the parent. happens in somatic cells
somatic cell
non sex cell
Steps of mitosis division
Interphase, mitosis, cytokinesis
Interphase
two phases G1 and G2. g1 organelles duplicate. G2 proteins synthesize to drive mitosis. cell grows and prepares to enter mitosis. S phase is when dna replicates but does not condense (happens between g1andg2) .
mitosis phase
prophase: dna condenses into chromosomes, microtubules phorm and anchored by centrioles. nuclear envelope breaks down.
- metaphase:chromosomes ALIGN at the middle of cell between the 2 poles. microtubules grow long enough to attach to centromeres.
- anaphase: Microtubules contract and separate sister chromatids
- telophase: nuclear envelope reforms chromosomes uncondense
cytokinesis
filaments band and contract around equator of cell producing two daughter cells to form. Mitosis: two daughter cells 46 chromosomes, meiosis: four daughter cells 23 chromosomes
growth factor
protein that stimulate cell to divide
meiosis
cell division reduces chromosomes to produce gametes with only half the chromosome of further cell. produced in sex organs. through phases g1, s, g2, meiosis1, meiosis2
alleles
different versions of the same gene are called alleles of a gene.
meiosis 1 phase
prophase1: nuclear envelope breaks down, microtubules begin, dna condenses to chromosome.
- metaphase: homologous chromosomes align at middle of cell in random alignment
- anaphase:homologous chromosomes are separated
- telophase1 and cytokinesis: cell divides produce 2 daughter cells.
- carries on to meiosis 2
meiosis 2 phase
- prophase2:microtubules lenthen
- metaphase2:chromosomes align at middle of cell
- anaphase2:sister chromatids separated
- telophase 2 and cytokinesis: four haploid daughter cells result nuclear envelope reforms
crossing over
occurs during prophase 1 of meiosis1. portions of chromosomes exchange from one homologous pair to the other member. increases genetic diversity
nondisjunction
the failure of chromosomes to seperate
trisomy
presence of extra chromosome
monosomy
absence of a chromosome
genetic variation
process of transmitting genes from one generation to the next with variation among genes
independent assortment
alleles for each gene are inherited mostly independent of each other
genotype
the genetic composition of an individual
phenotype
physical traits of an individual
heterozygous
two different alleles for a gene
homozygous
two copies of same allele for a gene
fig. 8.11 from textbook. what are the chances a hemophiliac male and unaffected female could have a baby that is a hemophiliac male?
none
a family tree that is used to follow human matings that have already occured
pedigree
incomplete dominance
phenotype of progeny is intermediate to that of both parent
codominance
both alleles of a given gene are expressed
x inactivation
one of 2 x chromosomes in females is inactivated and genes residing on it are not expressed. inactivation passed to all daughter cells.
mutation
changes to dna sequences that effect protein structure and function.
neutral mutation changes to dna that do not result in a different amino acid being incorporated. can result in frameshift mutations that change protein drastically
gene expression
- given cell only expresses small % of genes organism posseses
- eukaryotic cells one of 5 ways:1 increasing transcription through use of proteins that stimulate RNA polymerase binding, 2. varying time that dna spends in the uncondensed active form, 3. altering mRNA lifespan, 4. slowing down or speeding up translation, 5. affecting protein life span
stem cells
undifferentiated cells that can be programmed to act as a variety of cell types. may allow scientists to treat degenerative diseases
human genome project
resulted in production of complete DNA sequence of humans
gene therapy
replacing defective genes or their products in an embryo or affected adult tissue. gene therapy is experimental but hold promise when scientist learn to target genes to the right location and express them in proper amounts
nuclear transfer
used to clone animals with desirable agricultural traits.
transcription
copying of dna gene into rna synthesized by rna polymerase.
translation
mRNA used to produce protein for which the gene encodes. needs mRNA, amino acids, ATP energy, ribosomes and tRNA
