Biology Midterm Exam

Forest Glen Middle School Bio Midterm

Independent Variable

stand-alone variable that is modified or changed in an experiment.

Dependent

the one that is measured and tested in an experiment and is NOT controlled, but rather, a direct result of the independent variable.

Inferences

Logical explanation based on evidence

Observations

Made using the senses

Credibility of Science acronym

CRAMP

Currency

Is the information presented in the study out of date?

Relevance

Is the research written at a scholarly level?

Author

Who is the author?

Accuracy

Does the information align with the other information on the topic?

Methodolgy

Is there a large enough sample size? Is there a control group? Multiple trials? Has it been published in a peer-reviewed scientific journal?

Purpose

Is the research trying to sell you something? Is there biased language?

Theory

Scientific explanation for patterns or events in nature that is supported by multiple lines of evidence and hypotheses that have been tested repeatedly. It is widely accepted, open to change, and can be used to make predictions.

Laws

Are generalizations and dervied from scientific facts that describe how the natural world bahaves under certain conditions.

Cell Theory

1) All organisms are composed of one of more cells
2) The cell is the basic unit of life for all living things
3) All cells are produced by the division of pre-existing cells

Theory of Spontaneous Generation

Explains that living things (such as maggots) come from non-living things (such as trash). Disproven by swan-neck.

What did Pasteur prove

Living things come from other living things

Polar Molecules

Have positive and negative charges and cause an unequal sharing of electrons between two molecules

Nonpolar Molecules

Have neutral charges and cause an equal sharing of electrons between two molecules

Structure of water

Polar molecule (two poles). Soluable, solvent. Form hydrogen bonds by joining nefativly charged oxygen to positive. High heat capacity, cohesive, and adhesive. Three states of matter.

Density of Water

As water freezes hydrogren expands and being more dense. Ice float on water.

How does water’s polarity influence its properties as a solvent?

it will be able to blend and mix with any ionic or polar substance. This is because a polar molecule has two oppositely charged poles, which both attracts the opposite poles of another, different molecule.

Adhesion

The attraction between different molecules

Cohesion

The attraction between similar molecules

Capillary Action

Adhesion overcomes cohesion.

Surface Tension

Property that allows water to resist an external force. Water’s hydrogen bonds generate its high surface tension.

High Specific Heat

Makes it resistant to temperature change, allowing life forms to maintain relively constant internal temperatures.

Monomer

Building block of a large molecule

Polymer

Long strand of monomers

Carbohydrate

monosaccharide/polymer. (C,H,O) Main source of energy in cells.

Lipid

glycerol and fatty acids/polymer. (C,H,O) Store energy

Protein

amino acid/polymer. (C,H,O,N) Longer-lasting energy source, fights infections, speed up the rate of chemical reactions

Nucleic Acids

(C,H,O,N,P) Capture and transfer ATP, and store and trandmit genetic information

Enzymes

Protiens that speed up reactions by lowering acrivation energy. Reusable and specific.

Similarities between light and electron microscopes

Both have two types that can produce 2D or 3D images when viewing speciments.

Differences between light and electron microscopes

light microscopes use visible light and one or more lenses, while electron microscopes shine a beam of electrons at the specimen. Only light microscopes can view living organisms, but electron microscopes have higher resolution and magnification.

Transmitting Electron Microscopes (TEM)

Produce 2D images of internal structures and has the highest magnification

Scanning Electron Microscope (SEM)

Produce 3D images of surface features

Prokaryotic Cells

Organisms whose cells lack a nucleus and other organelles.

Eukaryotic Cells

Any cell or organism that possesses a clearly defined nucleus

Strucutes of a typical Eukaryotic cell

1) Vacuole
2) Mitochondria
3) Lysome
4) Nucleus
5) Cell Membrane
6) Golgi Apparatus
7) Ribosome
8) Smooth Endoplasmic Retuculum
9) Rough Endoplasmic Retuculum
10) Cytoplasm
11) Neceolus
12) Centriole
13) Chlorplast
14) Cell Wall
15) Microfilaments
16) Microtubles
17) Cytoskeleton

Similarities betwen plant and animal cells

mitochondria, lysosome, nucleus, membrane, Golg apparatus, ribosome, smooth ER, rough ER, cytoplasm, nucleolus

Differences betwen plant and animal cells

Plant cells only have chloroplasts, cell wall, large central vacuole

Protiens (cell membrane)

Form channels and pumps that help to move materials, help move or change shape

Carbohydrates (cell membrane)

allows individual cells to identify one another

Chloresterol (cell membrane)

Helps with fluidity and and acts as a buffer

Osmosis

The movement of water molecules across a selectively permeable membrane from an area of low solute concentration to an area of high solute concentration.

Diffusion

when substances flow from a high concentration to a low concentration until equilibrium is reached.

Facilitated Diffusion

diffusion using special protein channels and carrier proteins to assist in the transport of large, charged molecules or ions across the membrane.

Active Transport

the movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy (ATP)

Homeostasis

maintained by regulation and by the exchange of materials and energy with its surroundings.

Selective Permeability

The ability of the cell membrane to control the flow of substances in and out of the cell

4 main functions of cell membrane

Phospholipids, carbohydrates, protein channels, cholesterol

Hypertonic

Water moves out

Hypotonic

Water moves in

Isotonic

No net movement

Adenosine triphosphate ATP

is a nucleic acid that stores and releases energy in its bonds when the cell needs it; removing a phosphate group (P) releases energy for chemical reactions to occur in the cell and ATP becomes ADP (adenosine diphosphate). When the cell has energy, the energy is stored in the bond when the phosphate group is added to the ADP.

Photosynthesis

6H20+6CO2 àC6H1206+6O2

(water + carbon dioxide) → (glucose + oxygen)

Reactants Products

Cellular Respiration

C6H12O6 + 6O2 → 6CO2+ 6H20 + ATP

(glucose + oxygen) → (water + carbon dioxide + ATP)

Reactants Products

Fermentation

when cells are not provided with oxygen in a timely manner; this process continues producing ATP until oxygen is available again; glucose is broken down as a source of energy.

Lactic Acid Fermentation

(muscle cells) Glucose → Lactic Acid + 2ATP

Alcoholic Fermentation Glucose à CO2 + Alcohol + 2ATP

Cellular Respiration (def)

Occurs in all living cells, food broken down, energy from glucose released, carbon dioxide given off, oxygen taken in, does not require light.

Photosynthesis

food synthesized (made), energy from the Sun stored in glucose, carbon dioxide taken in, oxygen given off, requires light, occurs in organisms called autotrophs (producers)

Dermal

the protective outer covering of plants

Vascular

the tissue that supports the plant body and transports water and nutrients; xylem and phloem

Ground

the tissue that produces and stores sugars, and support

Roots

absorb and store water and nutrients from soil Root hair increases surface area, root hair cells are always dividing (mitosis).

Stems

transports water, sugar, and minerals; provide support and connection, produces leaves, branches, and flowers. Cambium – a layer of actively dividing cells between the xylem and the phloem, responsible for leaf and stem growth

Leaves

photosynthesis, transpiration, light absorption, and gas exchange.

Flowers

reproductive organs that attract pollinators. Made of 4 specialized leaves; sepals, petals, stamens, and carpels. Sepals protect the flower while its developing, while the bright color of the petals to attract pollinators to the flower.

Fruit

the fertilized ovary of a flower; a structure that encloses and protects a seed.

Seed

A plant embryo

Sexual Reproduction in plants

When the pollen from an anther is transferred to the stigma.

Self-Fertilization

occurs when the pollen from an anther fertilizes the eggs on the same flower.

Cross-fertilization

occurs when the pollen is transferred to the stigma of another plant.

Asexual Reproduction

occurs through budding, fragmentation, vegetative propagation, and spore formation. No flowers are required for this method. Chromosome number is maintained reproduction. The offspring is genetically identical to its parent.

Cones

Reproductive structure of conifers

Xylem

Transports water and minerals upwards the plant from roots to leaves

Phloem

Transports foods and nutrients throughout the entire plant

Meristems

Responsible for plant growth

Why are cells small?

Larger size comes with more demands

Interphase has 4 parts:

G0 resting phase
G1 Growth and normal functions
S DNA replication
G2 organelle replication

Chromosome

a segment of DNA that becomes visible during Prophase.

Chromatin

A highly organized condensed structure made up of DNA, RNA, and proteins that forms the chromosomes in the nucleus of a cell.

Sister Chromatids

two full-length DNA molecules joined together at the centromere, formed during DNA Replication

Homologous Chromosomes

chromosome pairs, one from each parent, that are similar in length, gene position and centromere location. Line up during meiosis.

Centromere

region where the cell’s spindle fibers attach to a chromosome.

Mitosis

1) Prophase
2) Metaphase
3) Anaphase
4) Telophase

Prophase

Nuclear membrane disappears, spindle fibers begin to form, chromatid pairs are visible

Metaphase

Chromatid pairs line up in the middle, fibers attatch

Anaphase

Spindle fibers pull chromosomes apart to opposite ends

Telophase

Spindle fibers disintegrate, chromosomes uncoils and two nuclear membranes form.

Cytokinesis

the division of a cell at the end of mitosis or meiosis, which separates into two daughter cells (mitosis and meiosis 1) or 4 daughter cells (meiosis 2)

Cancer relate to cell cycle

Uncontrolled cell growth, caused by mutations in the genes that control the cell cycle.

Stages if Meiosis

1) Phrophase 1
2) Metaphase 1
3) Anaphase 1
4) Telophase 1
5) Phophase 2
6) Metaphase 2
7) Anaphase 2
8) Telophase 2

Basic Structure of DNA

two linked strands that wind around each other to resemble a twisted ladder — a shape known as a double helix

Why DNA Replication is Semiconservative

The old strand is conserved or saved and used as a template to create a new complementary strand. Make a complementary strand for the following DNA sequence:

ACGTAAGCT

Why is the genetic code is universal

All known organisms have the same four nucleotide bases (adenine, cytosine, guanine and thymine) but are different due to different arrangements of these nucleotide bases.

Role of messenger RNA

Carry instructions for polypeptide synthesis from the nucleus to the ribosomes in the cytoplasm

The of ribosomal RNA

Assemble proteins by linking amino acids together

Role of transfer RNA

Carry amino acids to the ribosomes and match them to the coded RNA message