Biology Flashcards: DNA, Cell Cycle, and Systems Overview

Nucleotide

composed of a sugar (deoxyribose), phosphate group, and nitrogenous base.

Nitrogenous bases in DNA

Adenine (A), Thymine (T), Cytosine (C), Guanine (G).

Base pairing with adenine

Thymine (A-T pairing).

Base pairing with cytosine

Guanine (C-G pairing).

Double helix structure discovery

James Watson and Francis Crick (with help from Rosalind Franklin's X-ray data).

Function of helicase

Unzips the DNA strand during replication.

Function of DNA polymerase

Adds complementary nucleotides during replication.

Semi-conservative model

Each new DNA molecule consists of one original strand and one new strand.

Transcription

The process of synthesizing mRNA from DNA in the nucleus.

Enzyme that synthesizes RNA from DNA

RNA polymerase.

Exons and introns

Exons code for proteins; introns are non-coding segments removed during RNA processing.

Translation

The process where ribosomes synthesize proteins using mRNA as a template.

Start codon

AUG, which codes for methionine.

Codon

A sequence of 3 nucleotides that codes for a specific amino acid.

Role of tRNA

Transfers amino acids to the ribosome during protein synthesis.

Stages of the cell cycle

Interphase (G1, S, G2), Mitosis (PMAT), Cytokinesis.

G1 phase

Cell grows and performs normal functions.

S phase

DNA replication.

G2 phase

Preparation for mitosis.

Phases of mitosis

Prophase, Metaphase, Anaphase, Telophase.

Prophase

Chromatin condenses into chromosomes; nuclear envelope breaks down.

Metaphase

Chromosomes align at the cell equator.

Anaphase

Sister chromatids are pulled apart to opposite poles.

Telophase

Nuclear membranes reform; chromosomes decondense.

Cytokinesis

Division of the cytoplasm, completing cell division.

Meiosis

A two-part cell division process that produces four haploid gametes.

Crossing over

Exchange of genetic material between homologous chromosomes in Prophase I.

Importance of meiosis

Creates genetic diversity and maintains chromosome number.

Difference between meiosis and mitosis

Meiosis: 2 divisions, 4 unique haploid cells; Mitosis: 1 division, 2 identical diploid cells.

Homologous chromosomes

Pairs of chromosomes with the same genes but possibly different alleles.

Circulatory system function

Transporting oxygen, nutrients, hormones, and waste.

Respiratory system function

Gas exchange; brings in oxygen and removes carbon dioxide.

Digestive system function

Breaks down food, absorbs nutrients, and eliminates waste.

Nervous system function

Processes information and coordinates body responses.

Endocrine system function

Secretes hormones that regulate growth, metabolism, and homeostasis.

Homeostasis

The body's ability to maintain a stable internal environment.