UPCAT Science 4 Biology

Classification of Life

Classification of Life

domain -> kingdom -> phylum -> class -> order -> family -> genus -> species

Organization of Life

biosphere -> biome -> ecosystem -> community -> population -> organism -> organ system -> organ -> tissue -> cell

Carbohydrates

sugars and polymers of sugars, composed of a carbonyl (C=O) and hydroxide group (-OH)

Monosaccharide

single carbon skeleton

Monosaccharide

glucose, galactose, fructose

Disaccharide

two monosaccharides linked by a glycosidic bond

Disaccharide

maltose [glucose + glucose], sucrose [glucose + fructose]

Polysaccharide

several linked monosaccharides

Polysaccharide

starch, glycogen, cellulose

Lipids

hydrophobic nonpolar hydrocarbon molecules

Fats

consist of a glycerol connected to a fatty acid through an easier linkage

Unsaturated Fat

contains a cis-double bond in the fatty acid, liquid at room temperature

Saturated Fat

no fatty acid double bonds, solid at room temperature

Trans Fat

contains a trans-double bond in the fatty acid

Phospholipids

lipids with a phosphate group attached to the glycerol, has a hydrophobic and hydrophilic end, compose the cell membrane

Steroids

carbon skeleton is composed of four fused rings (e.g., cholesterol)

Proteins

consist of one or more chains of amino acids

Amino Acid

consists of an amino group and carboxyl group; there are 20 kinds of these

Nucleic Acids

polymers of nucleotides (e.g., DNA and RNA)

Nucleotide

contains a nitrogenous base (purines or pyrimidines), five-carbon sugar, and a phosphate group

Purines

cytosine (C), thymine (T), uracil (U)

Pyrimidines

adenine (A), guanine (G)

Nucleus

control center; houses genetic material

Ribosome

free-floating or attached; site of protein synthesis

Smooth endoplasmic reticulum

site of lipid synthesis and carbohydrate metabolism

Rough endoplasmic reticulum

synthesizer of membranes and proteins; has attached ribosomes

Golgi apparatus

modifier, sorter, and shipper of materials throughout the cell

Lysosome

digests celular materials

Vacuoles

storage sac for water and nutrients

Mitochondrion

site of cellular respiration

Chloroplast

site of photosynthesis

Peroxisome

producer of hydrogen peroxide and other enzymes involved in metabolic reactions

Cytoplasms

gel-like substance that fills the cell; site of most biochemical reactions

Plasmodesmata

pores between cell walls that allow intercellular communication

Cell membrane

semi-permeable layer that surrounds the cytoplasm

Cell wall

surrounds and protects the cell membrane

Lysosome

absent in plant cell but present in animal cell

Centrosome with centriole

absent in plant cell but present in animal cell

Chloroplast

present in plant cell but absent in animal cell

Vacuole

present (central and relatively larger) in plant cell and also present in animal cell

Cell wall

present in plant cell but absent in animal cell

Plasmodesmata

present in plant cell but absent in animal cell

Passive transport

adenosine triphosphate (ATP) is not required

Diffusion

movement of substances from a higher to a lower concentration

Osmosis

movement of water towards the side of the membrane with a higher solute concentration

Hypotonic

a solution relative to the cell can be this, lower solute concentration

Hypertonic

a solution relative to the cell can be this, higher solute concentration,

Isotonic

same solute concentration

Active transport

use of ATP to deliver nutrients opposite a concentration gradient

Exocytosis

vesicles attach to the cell membrane and release their contents

Endocytosis

molecules enter the cell through phagocytosis (cell eating) or pinocytosis (cell drinking)

Photosynthesis

6CO2 + 6H20 --light chlorophyll--> C6H12O6 + 6O2

carbon dioxide + water --light chlorophyll--> glucose + oxygen

Light Reactions

1. photons from light enter a photosystem which excites a single electron

2. water is split into electrons. H+ , and O2; the O2 is released as a by-product and the H+ is released into the thylakoid for future use

3. the excited electrons pass the energy along an electron transport chain, producing ATP in process

4. NADP+ is the final electron acceptor and is converted into NADPH

Calvin Cycle

1. carbon fixation and reduction of RuBP by CO2 converts it into G3P, which can be further processed into glucose

2. the fixed and reduced RuBP is then converted back to be ready for the next cycle; the whole cycle consumes ATP and NADPH

Carbon fixation

phase one of calvin cycle

Reduction

phase two of calvin cycle

Regeneration of RuBP

phase three of calvin cycle

Glycolysis

breakdown of glucose and investment of 2 ATP to produce pyruvate, 4 ATP, and NADH

Pyruvate Oxidation

pyruvate is oxidized into acetyl CoA, producing CO2 and transforming NADH into NAD+ in the process

Citric Acid/ Krebs Cycle

1. acetyl CoA reacts with oxaloacetate, which undergoes another series of reactions, reducing NAD+ into NADH, FAD+ into FADH2, ADP into ATP, and producing CO2; 2 ATM is produced per molecule of glucose

2. oxaloacetate is converted back to original form to be used in the next cycle

Oxidative Phosphorylation/Electro Transport Chain (ETC)

electrons are transported from NADH and passed on until it reaches O2, converting it into water

Chemiosmosis

ETC / H+ ions travel through ATP synthase, allowing it to synthesize ADP into ATP; 32 to 34 ATP is produced

Fermentation

occurs when there is no O2 present after glycolysis

Alcohol fermentation

pyruvate is converted into ethanol

Lactic acid fermentation

pyruvate is converted into lactate

Glycolysis

takes place in the cytoplasm, no oxygen needed, 2 net ATP is produced

Citric acid cycle (Krebs Cycle)

occurs in the mitochondrial matrix, oxygen is needed, 2 net ATP is produced

Electron transport chain (ETC)

occurs in the mitochondria, oxygen is needed, 32-34 net atp is produced

occurs in the cytoplasm, no oxygen needed, 2 net atp is produced

Alcohol fermentation

Lactic acid fermentation

occurs in the cytoplasm, no oxugen needed, 2 net atp is produced

occurs in the cytoplasm, no oxygen needed, 2 net atp is produced

Lactic acid fermentation

G1, G2-phase

cell growth and metabolism phase

S-phase

DNA synthesis phase that occurs between G1 and G2, duplication of chromosomes occurs

Mitotic Phase (M)

consists of prophase, prometaphase, metaphase, anaphase, and telophase

Prophase

nucleolus disappears, mitotic spindle forms, duplicated chromosomes appear as sister chromatids, centrosomes move in opposite directions

Prometaphase

nuclear envelope disappears, chromosomes become condensed, sister chromatids captured by kinetochore microtubules, mitotic spindle attaches to kinetochore

Metaphase

centrosomes now at opposite sides of cell and chromosomes align at metaphase plate

Anaphase

sister chromatids break apart from each other, shortening of microtubules pulls chromatids toward opposite ends, cell elongates

Telophase

start of cytokinesis (C) and formation of cleavage furrow, nuclear envelopes and nucleolus form, chromosomes become less condensed

Centrosome

contains material that function in organizing mitotic spindles

Centromere

attachment point of two sister chromatids

Kinetochore

site of attachment of mitotic spindle to chromosomes

Meiosis

haploid and diploid

Haploid

N number of chromosomes

Diploid

2N number of chromosomes

Humans

N=23

Meiosis I

similar to mitosis, produces 2 diploid daughter cells

Meiosis II

occurs right after meiosis I, produces 2 haploid daughter cells each (for parent cell, meiosis produces 4 haploid daughter cells)

Meiosis

has synapsis during prophase I

Meiosis

metaphase I aligns two chromatids at a time, compared to one for mitosis

Meiosis

produces 4 haploid daughter cells with different genetic material

Mitosis

produces 2 diploid daughter cells with same genetic material

Digestive System

food processing involves ingestion (eating), digestion (breakdown), absorption (uptake of nutrients), and elimination (passage out of the body)

Mouth/Oral Cavity

site of ingestion and mechanical digestion

Esophagus

moves bolus (mechanically ingested food) from mouth to stomach

Stomach

digests proteins and adds gastric juice, producing chyme

Small Intestine

site of most of enzymatic hydrolysis

Pancreas

produces an alkaline solution to stabilize acidic chyme

Liver

creates bile that aids in digestion of lipids

Gallbladder

stores bile