Biology, Unit 1 Flashcards
CELL
The smallest unit that can perform all life processes; covered by a membrane and have DNA and cytoplasm
first person to describe cell
Hooke
Cell theory (part 1)
All organisms are mode of one or more cells
Cell theory (part 2)
The cell is the basic unit of all living things
Cell theory (part 3)
All cells come from living cells
three parts of cells
Cell membrane/cytoplasm; organelles; DNA
cell membrane
A (protective) phospholipid layer that covers a cell’s surface; acts as a barrier between the inside of a cell and the cell’s enviornment
cytoplasm
Fluid inside the cell
organelles
One of the small bodies in a cell’s cytoplasm that are specialized to perform a specific task
DNA
Dioxyribonucleic acid; molecule present in all living cells; the genetic material that carries inherited characteristics; information needed to make new cells and new organisms
types of eukaryotic cells
plant; animal
cell wall
A stiff structure that supports the cell and membrane
ribosome
Organelle that makes proteins (site of protein synthesis); composed of RNA and proteins
nucleus
Contains the cell’s genetic materials
endoplasmic reticulum
A system of membranes with many folds in which proteins, lipids, and other materials are made
mitochondrion
The main power source for the cell
chloroplasts
organelles in which photosynthesis takes place
cytoskeleton
web of proteins inside the cell
vesicle
a small sac that surrounds material to be moved
Golgi complex
packages and distributes proteins
lysosomes
digestive proteins
vacuoles
plant cell’s stores of water and other liquids
cell cycle
birth; growth; division
chromosomes
where DNA is stored; in eukaryotic cells: one of the structures in the nucleus that are made up of 1) DNA and 2) protein; in prokaryotic cells: the main ring of DNA
How do prokaryotic cells divide?
- chromosomes condense from strands into rod structures; 2. membrane dissolves, chromitads align at equator; 3. chromitads separate and move to opposite sides of the cell; 4. cells split/pinch in two
three steps of eukaryotic division
interphase; mitoses; cytokinesis
interphase
duplication of the chromosomes
MITOSIS
the division of eukaryotic cells
cytokinesis
the division of cytoplasm
Why does a cell make a copy of its DNA before it divides?
the other cell must have a copy
Why is cell division in eukaryotic cells more complex than in prokaryotic cells?
eukaryotic cells have a nucleus, but prokaryotic cells do not
GENES
one set of instructions for an inherited trait
four bases found in DNA nucleotides
adenine, thymine, guanine, cytosine
three parts of a nucleotide
phosphate, sugar, base
How are the four kinds of DNA nucleotides different from each other
they each have different bases
What are the sides of the DNA “ladder” made of?
sugar and phosphates
In what form is the DNA in the nucleus?
chromatin / loose
What is chromatin made of?
DNA, proteins
Where is DNA found in a eukaryotic cell?
nucleus/chromosome
amino acid
chemical units that are chained together to form proteins; there are 3 bases that code for each amino acid; there are 20 amino acids
RNA
ribonucleic acid - a molecule present in all living cells and that plays a role in protein production
How does the shape of RNA and DNA differ?
RNA is a straight, single strand that is not a helix while DNA is a double-stranded helix
mutation
A change in the nucleotide-base sequence of a gene or DNA molecule
genetic engineering
when scientists manipulate individual genes within organisms
DNA fingerprinting
methods for identifying the unique patterns in an individual’s DNA
heredity
the passing on of genetic traits from parent to offspring
Gregor Mendel
born in 1822 and grew up on a farm, learning in a monastery; discovered principles of trait inheritance
dominant trait
a trait observed in the first generation where parents that have different traits are bred
recessive trait
a trait that reappears in the second generation after disappearing in the first generation when parents with different traits are bred
alleles
one of the alternative forms of a gene that governs a characteristic such as hair color
phenotype
an organism’s appearance or other detectable characteristic
genotype
the entire genetic makeup of an organism; also the combination of genes for one or more traits
Why do some genotypes have the same phenotype?
The dominant gene in the genotype is what gets expressed in the phenotype, even though two genotypes might differ due to recessive gene
Give an example of a single trait that is affected by more than one gene.
skin color
What affects traits other than genes?
environment
two types of reproduction
sexual; asexual
sexual reproduction
reproduction in which the sex cells from 2 parents unite to produce offspring that share traits from both parents
asexual reproduction
reproduction that does not involve the union of sex cells and in which one parent produces a genetically identical offspring
homologous chromosomes
chromosomes that have the same sequence of genes and the same structure
sex chromosomes
one of the pair of chromosomes that determines the sex of an individual
MEIOSIS
a process in cell division during which the number of chromosomes decreases to half the original number by two divisions in the nucleus, which results in the production of sex cells
sex-linked disorder
a disorder caused by damage on an X chromosome (males are more prone since they only have one X chromosome)
2 ways seedless vascular plants can reproduce
-Asexual -Sexual
2 stages of seedless non-vascular plants life cycle
-Sporophyte -Gametophyte
Fossil fuels
Fuel from living things decaying over time in the ground
Where does coal come from
Seedless vascular plants
How do seedless Vascular plants help make soil?
They break down rock
Non-vascular plants are usually very small. How does their structure limit their size
They don’t have vascular tissue to transpose nutrients
Rhizome (define)
A horizontal, underground stem that produces new leaves, shoots, and roots.
Why are seedless vascular plants larger than seedless non-vascular plants?
They have vascular tissue
ecology
The study of the interactions of living organisms with one another and with their environment.
HABITAT
place where an organism or a community of organisms lives.
fungi
a kingdom made up of non-green, eukaryotic organisms that have no means of movement, reproduce by using spores, and get food by breaking down substances in their surroundings and absorbing the nutrients
spores
a reproductive cell or multicellular structure that is resistant to stressful environmental conditions and that can develop into an adult without fusing with another cell
Yeast
single-celled most of its life, eukaryotic, reproduce asexually by budding or binary fission, produce ascospores.
CLASSIFICATION
the division of organisms into groups, or classes, based upon specific characteristics