Exam #1 Flashcards
characteristics of living organisms
order
reproduction
growth & development
energy processing
regulation/homeostasis
response to stimuli/environment
evolutionary adaptation
cell: basic unit of life
- smallest unit capable of life functions
growth, metabolism, response to stimuli, reproduction - higher levels of organization (tissues, organs) are built from cells
- only eukaryotic cells (like plants and animals) have a nucleus, while prokaryotic cells (like bacteria) do not
understanding evolution
evolution is the process by which species change over time through adaptation and natural selection
- evolution does not mean species stay the same; it reflects ongoing change. this change is driven by natural factors, such as mutations, genetic drift and environmental pressures
phylogenetic trees
phylogenetic trees represent the evolutionary relationships among species
branch points
represent the most recent common ancestor of the species diverging from that point
shows how species are related through evolution
sources of genetic variation
crucial for evolution and adaptation. Adaptations occur due to genetic variations and environmental pressures, not an organism’s needs
natural selection - environmental survival pressures, gene flow, genetic drift, mutation
unifying themes of biology
important theme for diversity - evolution: explains the variety and complexity of life on earth
the scientific method
a systematic approach to investigation and discovery in science
1. observation
2. question
3. hypothesis formation
4. prediction
5. experiment
6. interpretation/ data analysis
7. conclusion/ new questions
prokaryotic cells
lack a nucleus and membrane-bound organelles; found in bacteria and archaea
eukaryotic cells
have a nucleus and membrane-bound organelles found in plants, animals, fungi and protists
prokaryotic & eukaryotic
have ribosomes and DNA
protons
positively charges particles found in the nucleus
neutrons
neutrally charged particles in the nucleus
electrons
negatively charged particles orbiting the nucleus
covalent bonds
form when atoms share electron pairs (strong bonds)
polar covalent bonds
the shared electrons have an unequal distribution, which leads to partial positive and negative regions on the molecule
non-polar covalent bonds
the shared electrons have an equal distribution
ionic bonds
ions that attract each other because of opposite charges
hydrogen bonds
bonds that occur between polar molecules (like water), contributing to properties like cohesion. The partial negative and partial positive charges on a molecule attract to each other
strongest bonds
covalent bonds - —– ionic bonds —- hydrogen
carbohydrates
used primarily for energy storage (glucose, starch)
monosaccharides
simple sugars, like glucose (building blocks)
polysaccharides
complex carbs like starch
proteins
made up of amino acids; responsible for structure, function and regulation of body tissues and organs
amino acids
20 different amino acids, some are hydrophobic, some are hydrophilic. they are the building blocks of proteins
lipids
hydrophobic molecules, important for long-term energy storage and cell membrane structure (fats, oils)
fatty acids - building blocks
fats
phospholipids
steroids
Nucleic Acids: DNA stores genetic information and RNA transmits genetic information for protein synthesis
DNA base pairs: A-T, C-G
RNA base pairs: A-U, C-G
Hydrophobic
molecules that repel water (lipids, fatty acids)
Hydrophilic
molecules that attract water (glucose, salts)
building blocks
mono - single building block
di - two
tri - three
poly - many
primary protein structure
the sequence of amino acids in polypeptide chain
secondary structure
alpha-helices and beta-sheets formed by hydrogen bonds between amino and carboxyl regions of the amino acids
tertiary structure
the interactions between the amino acid side chain facilitate 3D structure
quaternary structure
multiple folded proteins come together to make a functional protein
amino acids
the building blocks (monomers) of proteins, linked together by peptide bonds
DNA (deoxyribonucleic Acid)
stores genetic information and is responsible for inheritance
RNA (Ribonucleic Acid)
involved in protein synthesis and gene regulation
transcription
the process of making RNA from DNA
occurs in the nucleus
mRNA
- capped, tailed, spliced, it is transported to the cytoplasm to be translated
RNA polymerase
transcription
the enzyme responsible for adding RNA nucleotides and transcribing the DNA into RNA
Transcription factors
proteins that help initiate transcription by recruiting RNA polymerase to the promoter region
mRNA processing
cap and tail: added to protect mRNA from degradation
splicing: removal of introns (non-coding sequences) and joining of exons (coding sequences)
translation
the process of synthesizing a polypeptide chain (protein) mRNA. Involves ribosomes, tRNA and mRNA
ribosomes
translation
organelles that carry out protein synthesis
codons
translation
three-nucleotide sequences in mRNA that code for amino acids
start codon
translation
AUG (signals the start)
stop codons
trigger the release factor to bind the ribosome and stops translation
tRNA
carries amino acids to the ribosome for incorporation into the growing polypeptide chain
